Testosterone Tag

Men with low testosterone are five to six times more likely to develop dementia. alz-journals.onlinelibrary.wiley.com

Brain Hormones Testosterone Dementia Neurodegeneration

Testosterone is the primary male sex hormone, crucial for maintaining fertility and maintaining male sexual characteristics. Some evidence suggests testosterone is neuroprotective. A recent study found that lower testosterone levels are linked with a higher risk for dementia.

The study involved 581 cognitively healthy older men living in China. Researchers assessed the men’s cognitive function and measured their levels of testosterone and neurofilament light chain, a structural protein that maintains neuronal health and connectivity. Neurofilament light chain is a biomarker for neuronal damage and degenerative diseases, including Alzheimer’s.

They found that men with lower testosterone levels were roughly five times more likely to experience cognitive decline than those with high levels. Those with low testosterone and high neurofilament light chain levels were approximately six times more likely to experience cognitive decline.

These findings suggest that lower testosterone and neurodegeneration synergistically contribute to cognitive decline in men. Learn more about low testosterone in this clip featuring Dr. Peter Attia.

Long-term estrogen treatment reduced androgen levels in female monkeys by up to 53% and increased cortisol levels. (2004) www.sciencedaily.com

Hormones Testosterone Estrogen Polyphenol

From the article:

“Our findings suggest that it might be important for women taking estrogen after menopause to also take androgen supplements – which can include testosterone,”

[…]

Half of the monkeys were given oral contraceptives, which contain estrogen, in their diets for 26 months. All animals then had their ovaries removed to make them menopausal.

For the next three years, the animals were divided into three groups based on diet. One group ate soy that didn’t contain isoflavones, which are natural plant estrogens; one group ate soy with the isoflavones intact, and one group’s diet was soy without isoflavones and Premarin [conjugated estrogen], or estrogen therapy, added.

[…]

The researchers measured levels of the major androgens, which include dehydroepiandrosterone sulfate (DHEA-S), androstenedione (A4), and testosterone. Monkeys who took the oral contraceptives before menopause had DHEA-S levels that were 27 percent lower than the monkeys who didn’t take contraceptives. Levels of A4 were 53 percent lower, and levels of testosterone were 50 percent lower. These effects did not continue into menopause.

In the postmenopausal phase of the study, treatment with soy plus Premarin resulted in DHEA-S levels that were 29 percent lower than the monkeys who ate soy without isoflavones (control group) and 35 percent lower than the group eating soy with isoflavones. Total levels of testosterone were 52 percent lower than the control group and 41 percent lower than the group eating soy with isoflavones.

The researchers had suspected that the plant estrogens would also suppress androgen production. While this didn’t prove true, they did find that these monkeys had smaller adrenal glands than monkeys that didn’t consume the isoflavones.

The adrenal gland, located near the kidneys, uses cholesterol to make the androgen hormones and to make cortisol, a hormone associated with high levels of stress. The researchers found that while estrogen treatment lowered levels of androgen hormones, levels of cortisol increased.

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Estrogen may protect against cocaine-induced brain dysfunction by improving brain blood flow - progesterone and testosterone may be detrimental.(2001) www.sciencedaily.com

Aging Hormones Testosterone Estrogen Addiction

From the article:

Lead researcher Marc Kaufman and his colleagues first established the rate of blood flow to the brain in male and female occasional cocaine users. An intravenous dose of cocaine (0.4 mg/kg) was administered to nine men and 13 women. Men were studied once while women were examined during different phases of their menstrual cycle phases (days 3-8, follicular phase and 18-24, leutial phase) after the beginning of menstruation.

[…]

In the follicular phase, when estrogen levels are high and progesterone levels are low, cocaine did not alter the amount of blood in the brain. By contrast, a 10 percent reduction in blood was found in women during their luteal menstrual cycle phase, when progesterone levels rise; male subjects incurred a 20 percent loss. These findings suggest that cocaine’s effects on blood vessels in the brain differ as a function of sex and menstrual cycle phase, and imply that progesterone in women and testosterone in men may enhance cocaine-induced vasoconstriction, while estrogen in women may blunt cocaine’s vascular effects.

[…]

Such benefits could extend beyond drug using populations. For example, treatments that improve brain blood flow might also benefit the elderly, many of whom experience reductions of blood flow to the brain as a result of aging.

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Estrogen and other sex hormones may be responsible for the higher prevalence of migraine in women, while testosterone may be protective. (2018) www.sciencedaily.com

Hormones Testosterone Estrogen Migraine

From the article:

Ferrer-Montiel and his team reviewed decades of literature on sex hormones, migraine sensitivity and cells' responses to migraine triggers to identify the role of specific hormones. Some (like testosterone) seem to protect against migraines, while others (like prolactin) appear to make migraines worse. They do this by making the cells' ion channels, which control the cells' reactions to outside stimuli, more or less vulnerable to migraine triggers.

Some hormones need much more research to determine their role. However, estrogen stands out as a key candidate for understanding migraine occurrence. It was first identified as a factor by the greater prevalence of migraine in menstruating women and the association of some types of migraine with period-related changes in hormone levels. The research team’s evidence now suggests that estrogen and changes in estrogen levels sensitize cells around the trigeminal nerve to stimuli. That makes it easier to trigger a migraine attack.

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Pubertal activation of estrogen receptor α in the medial amygdala is essential for the full expression of male social behavior in mice. (2016) www.sciencedaily.com

Brain Hormones Behavior Testosterone Estrogen

From the article:

Behavioral responses to sexually receptive females such as mounting, and toward intruder males such as biting and attacks, were recorded in adult mice. The reduction of both sexual and aggressive behavior by ERα [estrogen receptor alpha] silencing in the MeA [medial amygdala] before puberty but not in adults suggests the importance of the receptor in this location during puberty. “ERα knockdown in the MeA may even have affected the onset of puberty itself,” first author Dr. Kazuhiro Sano says. “This contrasts with the silencing of ERα in the MPOA [medial preoptic area], which reduced sexual but not aggressive behavior in mice, regardless of the time of knockdown treatment.” These findings suggest that ERα gene expression in the MPOA does not control male aggression through either the organizational role of testosterone at puberty, or its regulatory role in adulthood.

To understand why ERα silencing in different areas of the brain had varying effects, the team examined MeA cells. They found that neuronal cells were greatly reduced in MeA in which ERα expression had been inhibited before puberty. “ERα in the MeA seems to be necessary for testosterone to masculinize the neural circuitry for social behavior during puberty,” corresponding author Dr. Sonoko Ogawa explains. “If this masculinization is incomplete, social signals that enable adults to express male social behavior may not function correctly.”

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Testosterone levels are subject to a circadian rhythm, peaking in the early morning hours and then falling by at least 43%. (2003) onlinelibrary.wiley.com

Aging Hormones Circadian Rhythm Testosterone

From the publication:

Total testosterone

Each subject in both the old and young groups showed a marked diurnal variation in serum total testosterone, with a minimum decrease (peak to nadir) of 43% of the peak value. In each group, 50% of the subjects reached a nadir of < 10 nmol/l, while all subjects in both groups had a peak level of > 10 nmol/l. […] A significant difference between the young and older mean total testosterone was shown at three sampling times: 06·00, 07·00 and 07·30 h, when the young group showed a higher mean concentration at each of the three times. In both groups, the acrophase occurred at 07·30 h.

Bioavailable testosterone

Both groups display a significant circadian rhythm. No significant difference was demonstrated in mesor or acrophase but a significant difference was shown in amplitude. The acrophase in both groups coincide at 07·24 h, similar to that for the total testosterone. Significant differences between the young and middle-aged groups in the mean bioavailable testosterone were seen at 04·30, 05·30, 06·00, 07·30 and 09·30 h.

Free testosterone

A highly significant circadian rhythm was observed in the young group and in the older group. As with the bioavailable testosterone, there was no significant difference between the two groups in mesor and acrophase but a significant difference was seen in amplitude. The acrophase was calculated as occurring at 07·18 h in the young group and 07·05 h in the older men. Significant differences in the mean free testosterone concentration were seen at 05·00, 05·30, 06·00, 06·30, 07·00, 07·30, 09·00, 09·30, 10·00 and 18·00 h.

Circadian desynchrony negatively affected rat Leydig cell function and thus testosterone production. (2022) www.nature.com

Hormones Circadian Rhythm Mitochondria Testosterone

From the publication:

CD [circadian desynchrony] was characterized by changed and decreased rhythmic locomotor activity and reduced blood testosterone. In the Leydig cells changed transcription of the clock genes (Bmal1, Clock, Cry1 and Reverba/b increased while Per1/2 reversed phase) was detected. This was followed by reduced transcription of genes (Star, Cyp11a1, and Hsd3b1/2) primarily involved in mitosteroidogenesis. In parallel, mitochondrial membrane potential (Δψi) and ATP production declined losing their characteristic oscillatory pattern. Also, the main markers of mitochondrial biogenesis (Ppargc1a, Nrf1, Tfam, Cytc), fusion (Mfn2), and mitophagy (Pink1 and Tfeb) were disturbed. Collectively, CD [circadian desynchrony] targets mitochondria in Leydig cells by reducing mitosteroidogenesis, mitoenergetics, and disturbing mitochondrial dynamics. These changes contribute to testosterone decline compromising androgen-dependent functions, including reproduction.

Use of food and supplements to regulate testosterone levels may be a promising therapeutic alternative to testosterone replacement therapy. (2021) www.imrpress.com

Diet Hormones Testosterone Supplements

From the publication:

Some foods and supplements influence testosterone levels in various animals. The two main mechanisms are the direct increase in testosterone levels or suppression of the decrease in testosterone production due to testicular toxicity. Foods or supplements raise testosterone production in three ways: 1) regulating LH [ luteinizing hormone], the hormone that stimulates the production of testosterone, 2) regulating testosterone synthase in the testis, and 3) regulating testosterone-degrading enzymes. In contrast, suppression of the decrease in testosterone depends on the antioxidant effect of the foods and supplements.

[…]

LH is a gonadotropin that is released by the pituitary glands. Garlic, l-carnitine, selenium, vitamin C, CoQ10, qleuropein, and resveratrol regulate the LH [ luteinizing hormone] secretion. Secreted LH acts on testis receptors and is involved in the synthesis of testosterone from cholesterol. Lactic acid bacteria enhance testosterone production by increasing Leydig cells in the testis. Linoleic acid, maca, and piperin raise testosterone levels by increasing the levels of enzymes involved in testosterone synthesis. These two pathways of testosterone production would be a promising target for treatment. Foods or supplements that have been shown to increase testosterone might act on these pathways. In contrast, testosterone is metabolized to estradiol by aromatase. Chrysin increased testosterone levels by inhibiting aromatase activity. Although detailed mechanistic studies and clinical trials are required to validate the findings, the effects of these foods on testosterone provide potential therapeutic options.

Low, rather than high testosterone and hyperestrogenism may favor prostate inflammation and benign prostate hyperplasia. (2019) www.sciencedirect.com

Hormones Testosterone Estrogen Prostate

From the publication:

Mounting evidence shows that low, rather than high, T[estosterone] levels favor prostate inflammation and that hyperestrogenism also may play a role. Considering all these data, we postulate that BPH results from the actions of multiple factors occurring together or at different time points, which can reinforce and favor their mutual detrimental effects. The initial steps in this process are likely to occur early in life with an overt or subclinical prostatitis, probably influenced by infectious agents. The resulting prostatic inflammation could be amplified and maintained by metabolic derangements occurring in such conditions as MetS [metabolic syndrome]. Low T and the relative hyperestrogenism secondary to MetS [metabolic syndrome] could further exacerbate the immune process, leading to a chronic inflammation. When prostatitis becomes chronic, a number of cytokines are produced that act in the tissue to maintain the pathological condition. On the other hand, several growth factors are secreted, and their elevated concentrations lead to prostate remodeling and enlargement. The resulting mechanical obstruction and inflammatory damage are the basis of BPH and its associated urinary symptoms.

[…]

In addition, treating hypogonadism, which frequently accompanies MetS, not only is not detrimental for the prostate, but also could even be a therapeutic resource for relieving urinary symptoms and limiting the inflammatory process in the prostate.

[…]

The apparent contradiction of these results with the success of 5-alpha reductase inhibitors in treating LUTS merits closer investigation. Undoubtedly, treatment with 5-alpha reductase inhibitors results in a prostate volume decrease, which in turn translates into an improvement in LUTS. Nonetheless, it should be kept in mind that studies assessing intraprostatic androgen levels have linked 5-alpha reductase inhibition with a decrease in DHT and an increase in T.

International organizations suggest a cut-off level between 300-350 ng/dl for testosterone deficiency. (2019) bjui-journals.onlinelibrary.wiley.com

Hormones Testosterone

From the publication From the publication:

The purpose of this paper is to analyze the guidelines for TTh [testosterone therapy] from international organizations and compare their recommendations.

[…]

All agree that TD [testosterone deficiency] is a clinical syndrome that requires a low testosterone level as well as signs and/or symptoms for a diagnosis to be made. The exact cut -off varies or is not provided, but the organizations suggest a cut -off level between 300 -350 ng/dl. All societies recommend routine laboratory monitoring within the first year and annually after. The guideline committees acknowledge limited data on cardiovascular disease and testosterone. The consensus is to withhold TTh within 3 -6 months of an MI or stroke or in patients with severe heart failure. Prostate cancer is another gray area. Although the consensus is that there is no data to suggest TTh causes prostate cancer.

Standard threshold for low testosterone may not apply to young men. (2022) www.eurekalert.org

Hormones Testosterone

From the article:

However, urologists are seeing a growing number of younger men with concerns related to testosterone deficiency – often with less-specific symptoms such as low energy and fatigue.

Diagnosing low testosterone in young men poses other challenges as well. The standard cutoff point for low testosterone is 300 nanograms per deciliter (300 ng/dL). However, that threshold is based on testosterone studies of older men, and overlooks the normal age-related decline in testosterone levels.

To develop a set of age-specific cutoff points, Dr. Zhu and colleagues from the University of Michigan Department of Urology analyzed data on nearly 1,500 men, aged 20 to 44 years

[…]

As expected, the testosterone levels decreased at older ages. Age specific cutoff points for low testosterone ranged from 409 ng/dL at age 20 to 24 years to 350 ng/dL at age 40 to 44 years – substantially higher than the standard cutoff point. Each one-year increase in age was associated with a 4.3 ng/dL decrease in testosterone level.

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Eating a pro-inflammatory diet increased the likelihood of testosterone deficiency by 30% in men (2021) www.eurekalert.org

Diet Hormones Testosterone

Men who eat a pro-inflammatory diet – rich in sugar, refined carbohydrates, and fats – are 30 percent more likely to have low testosterone levels, a 2021 study found. Having obesity nearly doubles this risk.

Researchers analyzed dietary records of more than 4,000 men living in the United States and assigned each diet a score that reflected the inflammatory nature of the foods the men ate. In general, highly refined foods such as snacks, sugary drinks, processed meat, and fried foods are pro-inflammatory, but fresh fruits, vegetables, nuts, legumes, and fish are anti-inflammatory. They also assessed the men’s sex hormone status.

They found that men whose diet scores indicated that they ate a pro-inflammatory diet had lower testosterone levels than those who ate an anti-inflammatory diet. Men with the highest pro-inflammatory diet scores were nearly 30 percent more likely to have low testosterone levels. After considering other factors that influence testosterone levels, such as age, race, caloric intake, smoking status, education level, and body mass index, men who had obesity and had the highest pro-inflammatory diet scores were nearly 60 percent more likely to have low testosterone levels.

Testosterone is a male sex hormone that plays important roles in reproduction and sexual function. As many as one-half of all men living in the United States have low testosterone levels, which can cause low libido, lack of energy, and low mood. Research has shown that low testosterone levels are associated with higher levels of pro-inflammatory cytokines in the body.

The findings from this study suggest that a pro-inflammatory diet promotes low testosterone levels in men, especially those who have obesity. Other studies suggest the risk of low testosterone quadruples in the setting of obesity and a pro-inflammatory diet. Choosing foods that reduce inflammation may be beneficial in restoring testosterone levels. Check out this smoothie recipe, which is rich in anti-inflammatory fruits and vegetables.

Read study abstract.

Sleep loss and lower sleep duration may be associated with lower morning, afternoon and 24-h testosterone levels. (2022) link.springer.com

Sleep Hormones Insulin Resistance Cortisol Testosterone

From the publication:

When epidemiological and interventional studies are considered collectively, sleep loss and lower sleep duration are associated with lower morning, afternoon and 24-h testosterone; as well as higher afternoon, but not morning or 24-h cortisol. These reciprocal changes imbalances anabolic-catabolic signaling because testosterone and cortisol are respectively the main anabolic and catabolic signals in man. Fixing testosterone-cortisol balance by means of a novel dual-hormone clamp mitigates the induction of insulin resistance by sleep restriction and provided the first proof-of-concept that the metabolic harm from sleep loss can be ameliorated by approaches that do not require sleeping more. Obstructive sleep apnea is associated with lower testosterone, even after controlling for age and obesity whereas the conclusion that continuous positive airway pressure therapy has no effect on testosterone is premature because available studies are underpowered and better-quality studies suggest otherwise. High dose testosterone therapy induces OSA [obstructive sleep apnea], but more physiological dosing may not; and this effect may be transient or may dissipate with longer term therapy.

A systematic review found strong positive evidence for the testosterone-boosting effects of Tongkat ali and Tribulus. (2020) www.nature.com

Hormones Testosterone Supplements

From the publication:

While, 13% of ingredients in this study were given A grades [Eurycoma longifolia (tongkat ali), Tribulus], meaning they had strong positive evidence supporting their use, 81% of ingredients received grades that determined their evidence was indeterminate (C grade) or completely lacking/negative (D grade). Overall, our results showed that 69% of ingredients in testosterone supplements have published evidence of their use in RCTs.

[…]

Although there are several ingredients with A level of evidence, their use should be considered with caution. The evaluation of their safety and effectiveness in conjunction with other components has not been evaluated. Moreover, it has become apparent that many patients often do not consult healthcare providers before trying these products. However, at this time there are still no published RCTs evaluating the efficacy of whole supplement products for testosterone or ED [erectile dysfunction].

Honey may have positive effects on testosterone levels in men. (2019) www.sciencedirect.com

Diet Hormones Testosterone

From the publication:

In conclusion, collectively, the main stream of this specific research approach reveals that oral administration of honey enhances serum testosterone level in males. The mechanisms by which honey increases serum testosterone may be by enhancing the production of luteinizing hormone, enhancing the viability of Leydig cells, reducing testicular oxidative injury, enhancing StAR gene expression, and inhibiting aromatase activity in the testes (Fig. 1). In addition, honey has been found to contain various bioactive compounds (e.g., phenolic acids) that may improve testosterone production. However, still, there is lack in the number of human studies in this research context. Therefore, conducting clinical trials that reveal the mechanisms of honey on serum testosterone level will be of great importance.

Fenugreek seed and ashwagandha may have positive effects on testosterone concentrations in men. (2020) academic.oup.com

Hormones Testosterone Supplements

From the publication:

From the 4 databases searched, there were 13 herbs identified in 32 studies, published between 2001 and 2019. The main findings of this review indicate that 2 herbal extracts, fenugreek seed extracts and ashwagandha root and root/leaf extracts, have positive effects on testosterone concentrations in men. Also, some evidence exists for another herb and herbal extract, Asian red ginseng and forskohlii root extract. Overall, 9 out of 32 studies demonstrated statistically significant increases in testosterone concentrations. Moreover, 6 studies out of 32 were judged as having a low risk of bias. Current evidence is largely based on young, nonclinical populations, with 16 out of 32 studies using men <40 y of age. Conclusions are moderated by the paucity of research for many herbs, the variation in dosages and extracts used, small sample sizes, and the heterogeneity of study characteristics. Also, further research is required before definitive conclusions on efficacy and safety can be made.

Testosterone appears to play an important role in maintaining bone mineral density and bone health in men. (2021) www.mdpi.com

Hormones Testosterone Bone

From the publication:

Bone fracture due to osteoporosis is an important issue in decreasing the quality of life for elderly men in the current aging society. Thus, osteoporosis and bone fracture prevention is a clinical concern for many clinicians. Moreover, testosterone has an important role in maintaining bone mineral density (BMD) among men. Some testosterone molecular mechanisms on bone metabolism have been currently established by many experimental data. Concurrent with a decrease in testosterone with age, various clinical symptoms and signs associated with testosterone decline, including decreased BMD, are known to occur in elderly men. However, the relationship between testosterone levels and osteoporosis development has been conflicting in human epidemiological studies. Thus, testosterone replacement therapy (TRT) is a useful tool for managing clinical symptoms caused by hypogonadism. Many recent studies support the benefit of TRT on BMD, especially in hypogonadal men with osteopenia and osteoporosis, although a few studies failed to demonstrate its effects. However, no evidence supporting the hypothesis that TRT can prevent the incidence of bone fracture exists. Currently, TRT should be considered as one of the treatment options to improve hypogonadal symptoms and BMD simultaneously in symptomatic hypogonadal men with osteopenia.

Testosterone appears to play an important role in maintaining bone mineral density and bone health in men. (2021) www.mdpi.com

Hormones Testosterone Bone

From the publication:

Bone fracture due to osteoporosis is an important issue in decreasing the quality of life for elderly men in the current aging society. Thus, osteoporosis and bone fracture prevention is a clinical concern for many clinicians. Moreover, testosterone has an important role in maintaining bone mineral density (BMD) among men. Some testosterone molecular mechanisms on bone metabolism have been currently established by many experimental data. Concurrent with a decrease in testosterone with age, various clinical symptoms and signs associated with testosterone decline, including decreased BMD, are known to occur in elderly men. However, the relationship between testosterone levels and osteoporosis development has been conflicting in human epidemiological studies. Thus, testosterone replacement therapy (TRT) is a useful tool for managing clinical symptoms caused by hypogonadism. Many recent studies support the benefit of TRT on BMD, especially in hypogonadal men with osteopenia and osteoporosis, although a few studies failed to demonstrate its effects. However, no evidence supporting the hypothesis that TRT can prevent the incidence of bone fracture exists. Currently, TRT should be considered as one of the treatment options to improve hypogonadal symptoms and BMD simultaneously in symptomatic hypogonadal men with osteopenia.

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Coenzyme Q10 may counteract testosterone reduction induced by chemical reproductive toxicants, rodent studies suggest. (2018) www.mdpi.com

Hormones Testosterone Supplements

From the publication:

In conclusion, thus far the studies conducted on human males generally reveal an insignificant effect of coenzyme Q10 supplementation on testosterone levels. Similarly, the studies conducted on animals, rather than the reproductive toxicity studies, did not show positive effectiveness of coenzyme Q10 on testosterone. However, coenzyme Q10 supplementation was found to counteract testosterone reduction induced by chemical reproductive toxicants, mainly by counteracting the destructive effect of the generated pro-oxidants. In addition, according to the peer-reviewed literature in this specific context of research, studies performed on human males have revealed no beneficial effects of coenzyme Q10 supplementation on infertile men. Thus, dietary supplements containing much lower doses may not have any influence on the studied subjects.

Quality of life in older hypogonadal men may be positively influenced by testosterone substitution. (2020) onlinelibrary.wiley.com

Hormones Depression Behavior Mental Health Anxiety Genetics Testosterone

From the publication:

Testosterone plays a pivotal role in maintaining balance within the multi-dimensional psychological network of mood, behaviour, self-perception and perceived quality of life in men of any age. Apart from classical forms of hypogonadism, low testosterone concentrations can also be seen in older men, described as an age- and comorbidity-driven functional hypogonadism and might relate to depressive symptoms exhibiting a wide array of clinical pictures ranging from dysthymia and fatigue over inertia, listlessness to hopelessness and suicidal thoughts. Also, various traits of anxiety, from unfocussed fear to phobic anxiousness and open panic syndromes, are influenced by testosterone. Correspondingly, anxiolysis is likely to be modulated by testosterone via stress resilience, threat vigilance and reward processing. The steroid modulates pro-active and re-active dimensions of aggression, which has to be seen within the context of gaining or maintaining status. This may also include other strategies impacting the social position: heroic or parochial altruism and non-aggressive paths of assertiveness, such as posture and social vigilance. Independent rather than relationship-associated self-construal and self-esteem influence risk-taking traits under the modulation of testosterone. In addition, the genetic setting of the androgen receptor modulates the role of testosterone in aspects regarding mood and personality. Dimensions of sexuality are rather important in this context, but are not target of this article and covered in another part of this special edition. Overall, the quality of life in older hypogonadal men can be positively influenced by testosterone substitution, as has been demonstrated in large placebo-controlled trials.

Testosterone is positively but weakly related to aggression, with no strong evidence of a causal relationship, meta-analysis suggests. (2020) www.sciencedirect.com

Hormones Behavior Testosterone

From the publication:

Testosterone is often considered a critical regulator of aggressive behaviour. There is castration/replacement evidence that testosterone indeed drives aggression in some species, but causal evidence in humans is generally lacking and/or—for the few studies that have pharmacologically manipulated testosterone concentrations—inconsistent. More often researchers have examined differences in baseline testosterone concentrations between groups known to differ in aggressiveness (e.g., violent vs non-violent criminals) or within a given sample using a correlational approach. Nevertheless, testosterone is not static but instead fluctuates in response to cues of challenge in the environment, and these challenge-induced fluctuations may more strongly regulate situation-specific aggressive behaviour. Here, we quantitatively summarize literature from all three approaches (baseline, change, and manipulation), providing the most comprehensive meta-analysis of these testosterone-aggression associations/effects in humans to date. Baseline testosterone shared a weak but significant association with aggression, an effect that was stronger and significant in men, but not women. Changes in T were positively correlated with aggression, an effect that was also stronger and significant in men, but not women. The causal effects of testosterone on human aggression were weaker yet, and not statistically significant.

Meta-analysis suggests association between testosterone treatment and alleviation of depressive symptoms in men. (2019) jamanetwork.com

Hormones Depression Mental Health Testosterone

From the publication:

To our knowledge, the present meta-analysis is the largest examination to date of the association of testosterone treatment with depressive symptoms in men, including 27 RCTs comprising 1890 men. Replicating and extending previous work, we show evidence for a moderate antidepressant association of testosterone treatment compared with placebo, identifying an effect size of the overall analysis of Hedges g of 0.21.

[…]

Irrespective of any bias, analysis of potential moderators revealed that dose was a likely moderator, indicating robust effects for dosages higher than 500 mg/wk (Figure 3B). Previous studies failed to detect testosterone dose-response relationships for mood, including for depressive symptoms.

[…]

Remarkably, initial testosterone status was not a moderator of the effect of testosterone treatment on depressive symptoms. This result contradicts a previously published study showing up to a 3-fold increased incidence of MDD in hypogonadal men.

Antidepressants can affect testosterone and estrogen levels. (2021) www.sciencedirect.com

Hormones Depression Drug Testosterone Estrogen

From the publication:

Firstly, according to the reviewed data from preclinical studies, SSRIs affect to a greater extent, both testosterone and estrogen serum levels compared to the rest of drug classes (Tables 1 and 3). In particular, more than 50% of the reviewed publications report changes in testosterone and estrogen levels after SSRI administration. The same conclusion cannot be drawn from the comparatively fewer studies that investigated other classes of monoaminergic antidepressants. Secondly, data indicated differences between acute and sub-chronic or chronic drug administration on testosterone and estrogen levels. On the one hand, acute antidepressant treatment either decreases or does not affect testosterone and estrogen levels. On the other hand, data from sub-chronic and chronic antidepressant treatment are conflicted, probably due to variable treatment duration and differences in the time and method of sampling. Furthermore, from our reviewed data it appears that testosterone levels are more frequently affected by antidepressants in comparison to estrogen. More specifically, the majority of studies found no changes in estrogen levels following drug administration, whereas the rest of the studies reported either increased or decreased levels of testosterone in both males and females (Tables 1 and 3). Unfortunately, inconsistencies in methods, i.e., inclusion of both sexes, doses, age, duration, and strain, as well as the technical difficulties in measuring low and variable estrogen levels account for the conflicting data and impede any firm conclusions.

Several environmental and lifestyle factors can lower testosterone levels. (2020) www.tandfonline.com

Vitamin D Diet Obesity Sleep Hormones Stress Magnesium Testosterone Zinc Polyphenol Oxidative Stress

From the publication:

Many factors, including external, environmental and internal factors, influence testosterone levels. The impact of energy intake derived from a testosterone-boosting diet depends on a human body mass. In the case of people of healthy body mass, insufficient energy intake may result in a reduction in testosterone levels in men. The same energy deficit in obese people, may, in turn, result in a neutral or positive impact on the levels of the hormone. Undoubtedly, nutritional deficiency, and particularly of such nutrients as zinc, magnesium, vitamin D, together with low polyphenols intake, affects the HPG [hypothalamic–pituitary–gonadal] axis. The levels of mental and oxidative stress can also adversely impact the axis. The higher the cortisol levels in a human body, or the higher its daily fluctuation, the lower the testosterone levels. What is more, the effect seems to be strengthened by excessive body weight, which is related to the increased oxidative stress affecting the functions of the Leydig cells. Other factors which might disrupt testosterone synthesis may be the length and quality of sleep. Even though the issue is relatively unknown, it appears that both sleep deprivation (shorter than five hours) and low quality of sleep (sleeping with the light on, sleeping during the day, under the influence of alcohol) impact the testosterone levels negatively.

Testosterone therapy may play a small role in temporarily exacerbating or inducing changes in obstructive sleep apnea. (2021) www.sciencedirect.com

Obesity Sleep Hormones Testosterone Weight Loss

From the publication:

The best current evidence suggests that short-term, high-dose testosterone administration mildly worsens OSA [obstructive sleep apnea]. Longer-term TTh [testosterone therapy] in subjects undergoing concomitant weight loss was shown to mildly worsen OSA but only initially. By 18 weeks, patients demonstrated return to baseline levels of OSA risk. These results suggest that TTh’s role in exacerbating OSA is small and may be time limited. However, it is also possible that weight loss acted as a confounding factor. Additional studies are needed to determine if men who are more obese at baseline have a higher risk of developing OSA with TTh than nonobese men. Why testosterone would have a timedependent effect, however, remains unanswered. Regarding the mechanisms by which TTh may worsen OSA, anatomic TTh-induced airway changes and altered sleep stage architecture have been largely refuted. The mechanism of action is more likely related to altered hypoxic and hypercapnic ventilatory response with testosterone administration, though work is still needed to resolve inconsistencies in currently available studies. Until these questions are more fully understood, clinicians may choose to exercise caution in prescribing TTh to individuals with severe, untreated OSA.

Obstructive sleep apnea may have a suppressive effect on serum testosterone levels in men, independent of BMI and age. (2021) onlinelibrary.wiley.com

Obesity Sleep Hormones Testosterone

Sleep apnea increases the risk of low testosterone.

Men with sleep apnea are more likely to have low testosterone levels, according to a 2021 study. Men with severe apnea are at the greatest risk of low testosterone.

Researchers reviewed the findings of 18 studies involving more than 1,800 men that examined links between sleep apnea and male testosterone levels. Then they analyzed a subset of the studies after matching the men’s age, body mass index, and severity of their sleep apnea.

They found that the men with sleep apnea were more likely to have low testosterone levels, even after considering their age and body mass index. However, the subset analysis revealed that this relationship was only notable for those with severe apnea.

Sleep apnea is a common, but serious, sleep disorder characterized by brief moments of paused or shallow breathing. People with sleep apnea are at greater risk of high blood pressure, stroke, abnormal heart rhythms, heart failure, diabetes, weight gain, and heart attacks.

This review identifies links between sleep apnea and testosterone levels. It also underscores the importance of diagnosing and treating sleep apnea, particularly among men whose apnea is more severe.

Read full publication.

Exogenous testosterone can temporarily impair fertility in men by inhibiting sperm cell differentiation. (2015) www.nature.com

Hormones Sex Testosterone

From the publication:

Exogenous testosterone considerably impairs spermatogenesis through suppression of the HPG [hypothalamic–pituitary–gonadal] axis, with decreased levels of follicle-stimulating hormone (FSH), luteinizing hormone and intratesticular testosterone. This effect seems to be most frequent or most profound with the use of intramuscular formulations compared with topical agents. The high number of men in their reproductive years who take testosterone, seems to be partly caused by the misconception that testosterone enhances fertility and a lack of knowledge about its contraceptive effects. This misunderstanding is not limited to patients or non-urologists, as 25% of urologists indicate that they would use testosterone for empirical male infertility treatment.

[…]

These studies demonstrate that, in most cases, azoospermia or severe oligospermia will resolve by 4–12 months after cessation of testosterone or other anabolic steroid use.

Improving sleep, diet, fitness, and weight may be alternatives to testosterone therapy. (2018) www.sciencedirect.com

Exercise Diet Sleep Hormones Stress Meditation Testosterone Weight Loss

From the publication:

Patient interest in fertility and testicular size preservation and a desire to avoid lifelong medical therapy with testosterone drives the need to identify non-TTh [non-testosterone therapy] for hypogonadism. Medical therapies that can stimulate endogenous testosterone production include hCG [human chorionic gonadotropin], AIs [aromatase inhibitors], and SERMs [selective estrogen receptor modulators], all of which demonstrate efficacy in increasing serum testosterone levels and good safety profiles. Natural therapies to increase testosterone production include diet and exercise, weight loss, improved sleep, decreasing stress, and varicocele repair. Diet, exercise, and weight loss provide a means to potentially reverse comorbidities that are closely linked to hypogonadism. Improvements in sleep quality and duration and decreasing stress are additional lifestyle modifications that can improve testosterone levels without the need for lifelong medication. Varicocele repair also can increase testosterone levels, although rigorous data supporting its use remain lacking. Patients considering TTh should be counseled on disease modification and the possibility of discontinuing TTh in the future, before initiation of therapy, and the alternatives discussed in this review also should be considered first in appropriate candidates.

[…]

Diet, exercise, and weight loss

– 12-wk lifestyle modification program involving aerobic exercise and diet modification significantly increased mean testosterone levels

– 52-wk program of diet and exercise significantly increased mean serum testosterone levels

– Individuals who lost 10% of weight between visits showed a significant increase in testosterone levels

– Weight loss through low-calorie diets or bariatric surgery was associated with significant increases in total testosterone levels

Improvements in sleep

– Men with OSA treated with UPPP had significant 3-mo postoperative increases in testosterone levels

– Restriction of sleep to 5 h/night decreased testosterone levels by 10-15%

Stress reduction

– Men with high stress levels had significantly lower serum testosterone levels compared with controls

– Men with higher work stress had higher than expected incidence of hypogonadism

Varicocele repair

– Varicocelectomy significantly increased mean testosterone levels

– Varicocele repair significantly increased testosterone levels

– Significantly increased total testosterone levels were found at 12-mo follow-up after varicocelectomy

– Mean serum total testosterone significantly increased after varicocelectomy

Existing studies do not provide a clear answer to the question of the benefits and risks of testosterone for the cardiovascular system. (2019) www.nature.com

Hormones Testosterone Cardiovascular

From the publication:

– Population studies suggest that low serum levels of endogenous testosterone are a risk factor for cardiovascular events, although these studies cannot establish causality or exclude reverse causality, and some of these associations might result from residual confounding.

– Although many retrospective studies show no association, some retrospective studies of prescription databases have shown a higher risk of cardiovascular events in men receiving testosterone, with the risk increasing early after treatment initiation.

– Meta-analyses of randomized, controlled trials of testosterone replacement therapy report conflicting findings, probably because the included trials lacked power or the duration was too short to assess cardiovascular events.

– The TRAVERSE trial, the first trial of testosterone therapy that is adequately powered to assess cardiovascular events, began in 2018, and its findings might take a decade to become available.

– Until the results of the TRAVERSE trial are available, clinicians should individualize testosterone treatment after having an informed discussion with their patients about the risks and benefits of testosterone replacement therapy.

Testosterone administration impaired cognitive empathy in women. (2011) www.sciencedaily.com

Hormones Behavior Testosterone Autism

From the article:

The new study has several important implications. First, that current levels of testosterone directly affect the ability to read someone else’s mind. This may help explain why on average women perform better on such tests than men, since men on average produce more testosterone than women.

Second, that the digit ratio (2D:4D), a marker of fetal testosterone, predicts the extent to which later testosterone has this effect. This suggests testosterone levels in the womb have an ‘organizing’ or long-range effect on later brain function. Finally, given that people with autism have difficulties in mind reading, and that autism affects males more often than females, the study provides further support for the androgen theory of autism.

From the publication:

Fetal testosterone is associated with a fixed somatic marker that can be indexed after birth: the length ratio of the right hand’s second (i.e., index) to fourth (i.e., ring) finger (2D:4D ratio). Males on average have a significantly lower 2D:4D ratio on their right hand and fetal testosterone is thought to underlie this sex difference, including its variability within the sexes. The reliability of 2D:4D ratio as a marker of fetal testosterone is substantiated by a large amount of correlational evidence in animals and humans. Moreover, meta-analytic data show that 2D:4D ratio is unaffected by later testosterone fluctuations or circulating levels of testosterone in adulthood. The ratio is therefore considered a useful, noninvasive marker of fetal testosterone.

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Men exposed to the scent of an ovulating woman subsequently displayed higher levels of testosterone. (2010) www.sciencedaily.com

Hormones Testosterone

From the article:

In two studies, women wore tee shirts for 3 nights during various phases of their menstrual cycles. Male volunteers smelled one of the tee shirts that had been worn by a female participant. In addition, some of the male volunteers smelled control tee shirts that had not been worn by anyone. Saliva samples for testosterone analysis were collected before and after the men smelled the shirts.

Results revealed that men who smelled tee shirts of ovulating women subsequently had higher levels of testosterone than men who smelled tee shirts worn by non-ovulating women or men who smelled the control shirts. In addition, after smelling the shirts, the men rated the odors on pleasantness and rated the shirts worn by ovulating women as the most pleasant smelling.

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A group of international experts takes strong stance on testosterone deficiency treatment. (2016) www.sciencedaily.com

Cancer Hormones Diabetes Testosterone Prostate Cardiovascular

From the article:

After examining the best available scientific evidence, Morgentaler and colleagues – who included experts with specialties in urology, endocrinology, diabetes, internal medicine, and basic science research – agreed on the following:

– TD [testosterone deficiency] is a well-established, clinically significant medical condition that negatively affects male sexuality, reproduction, general health and quality of life.

– Symptoms and signs of TD occur as a result of low levels of testosterone and may benefit from treatment regardless of whether there is an identified underlying origin.

– TD is a global public health concern.

– Testosterone therapy for men with TD is effective, rational, and evidence-based.

– There is no testosterone concentration threshold that reliably distinguishes those who will respond to treatment from those who will not.

– There is no scientific basis for any age-specific recommendations against the use of testosterone therapy in adult males.

– The evidence does not support increased risks of cardiovascular events with testosterone therapy.

– The evidence does not support increased risk of prostate cancer with testosterone therapy.

– The evidence supports a major research initiative to explore possible benefits of testosterone therapy for cardiometabolic disease, including diabetes.

“It will be surprising to those unfamiliar with the literature to learn how weak the evidence is supporting the alleged risks of cardiovascular disease and prostate cancer,” said Michael Zitzmann, MD, vice-chair of the conference and a Professor in the Centre for Reproductive Medicine and Andrology at the University of Muenster in Germany. “Indeed, there is substantial data suggesting there may actually be cardio-protective benefits of testosterone therapy.”

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High-dose testosterone treatment increased serotonin transporter binding in transgender people. (2015) www.sciencedaily.com

Hormones Depression Mental Health Neurotransmitter Testosterone

From the article:

As they grow older and as their sex hormone output falls, men suffer more commonly from depression and some studies have already demonstrated a positive effect of testosterone supplementation on the moods of the test subjects. Now, the study led by Rupert Lanzenberger from the University Department of Psychiatry and Psychotherapy has demonstrated for the first time worldwide that testosterone increases the number of serotonin transporters (proteins) in the human brain. These proteins regulate the concentration of serotonin and are also the target for antidepressants.

Serotonin transporters increased after just four weeks of hormone therapy

[…]

“The study has shown that testosterone increases the potential binding sites for commonly prescribed antidepressants such as SSRIs in the brain and therefore provides major insights into how sex hormones affect the human brain and gender differences in psychiatric illnesses,” says Siegfried Kasper, Head of the University Department of Psychiatry and Psychotherapy at the MedUni Vienna.

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Men with borderline testosterone levels may be at risk for depression. (2015) www.sciencedaily.com

Hormones Depression Mental Health Testosterone

From the article:

The number of men having their testosterone levels checked has increased dramatically. Studies of the possible association between depression and serum testosterone show inconsistent results, and few studies have been published about adult men referred for the management of borderline testosterone.

Dr. Irwig and his colleagues studied 200 adult men between 20 and 77 years of age whose testosterone levels were borderline (between 200 and 350 nanograms per deciliter).

[…]

Using a score of 10 or higher on the PHQ-9 [Patient Health Questionnaire 9], 56% of the study participants had significant depressive symptoms, known diagnosis of depression and/or use of an antidepressant. Their rates of depressive symptoms were markedly higher than the 15 to 22% in an ethnically diverse sample of primary care patients and the 5.6% among overweight and obese US adults.

The population also had a high prevalence of overweight (39%), obesity (40%) and physical inactivity; other than walking, 51% of the men did not engage in regular exercise. The most common symptoms reported were erectile dysfunction (78%), low libido (69%) and low energy (52%).

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High testosterone levels may increase the risk for aggression, hallucinations and other acting-out behaviors in men with Alzheimer's. (2014) www.sciencedaily.com

Alzheimer's Hormones Testosterone

From the article:

Studies have found that having lower testosterone levels increased the risk for developing Alzheimer’s disease, said Dr. James Hall, Professor of Psychiatry and Behavioral Health.

“But once someone already has Alzheimer’s, higher levels of testosterone are related to acting-out behaviors,” he said. “Those behaviors, such as agitation and delusions, occur at some point in at least 70 percent of Alzheimer’s patients.”

[…]

For the study, 87 elderly men with mild to moderate Alzheimer’s disease were evaluated. Dr. Hall found the likelihood of having hallucinations was 5.5 times greater for the men with higher levels of testosterone than those with lower levels.

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Research shows a 23% overlap between the genes that control testosterone and those that regulate body fat composition in men (2008) www.sciencedaily.com

Hormones Fat Genetics Testosterone

From the article:

A strong correlation was found between sex hormones and body fat, which was predominantly due to shared genes. Specifically, testosterone and SHBG both showed a 23% genetic correlation with body fat, and SHBG [sex hormone-binding globulin] showed a 29% link with whole body fat. There was no link in terms of environmental factors between sex hormones and body composition.

When measured individually, testosterone had the highest heritability estimate of the sex hormones at 0.65 (heritability estimates are measured on a scale between 0 and 1, with 1 equalling 100% genetic influence). SHBG, weight and body fat also had high heritability estimates of 0.73, 0.83 and 0.65, respectively. Such high heritability values are similar to those previously published, and indicate that circulating testosterone levels are approximately 60% influenced by genes.

Previous studies have shown a well-established relationship between testosterone and body fat composition. For example, men with low testosterone levels are characterised by a high body fat percentage.

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High testosterone may indirectly weaken immune response to vaccination in men by interacting with related genes. (2013) www.sciencedaily.com

Hormones Immune System Vaccine Testosterone

From the article:

In the study, women had a generally stronger antibody response to the vaccine than men. But the average response mounted by men with relatively low testosterone levels was more or less equivalent to that of women.

[…]

Women are known to have, on average, higher blood levels of signaling proteins that immune cells pass back and fort to jump-start inflammation, a key component of immune-system activation. Furthermore, previous research in animals and in cell-culture experiments has established that testosterone has anti-inflammatory properties, suggesting a possible interaction between the male sex hormone and immune response.

[…]

However, the new study found no connection between circulating levels of pro-inflammatory proteins and responsiveness to the flu vaccine. Nor does testosterone appear to directly chill immune response; rather, it seems to interact with a set of genes in a way that damps that response, said the study’s senior author, Mark Davis, PhD, professor of microbiology and immunology and director of Stanford’s Institute for Immunity, Transplantation and Infection.

[…]

Men are prone to suffer wounds from their competitive encounters, not to mention from their traditional roles in hunting, defending kin and hauling things around, increasing their infection risk.

While it’s good to have a decent immune response to pathogens, an overreaction to them – as occurs in highly virulent influenza strains, SARS, dengue and many other diseases – can be more damaging than the pathogen itself. Women, with their robust immune responses, are twice as susceptible as men to death from the systemic inflammatory overdrive called sepsis. So perhaps, Davis suggests, having a somewhat weakened (but not too weak) immune system can prove more lifesaving than life-threatening for a dominant male in the prime of life.

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Testosterone levels improved in obese men following a common weight-loss operation. (2015) www.eurekalert.org

Obesity Hormones Testosterone Weight Loss

From the article:

The aim of the study was to investigate the effect of surgical weight loss following sleeve gastrectomy [removement of about 75 percent of the stomach] on serum testosterone, DHEA (a precursor to testosterone), and prostate-specific antigen (PSA). This clinical study involved 24 obese male patients undergoing gastric sleeve surgery, also called sleeve gastrectomy, at Stanford Hospital. Serum testosterone, DHEA, and PSA were measured before and at three, six, and 12 months after the procedure.

The researchers found that the study group experienced a significant increase in average serum testosterone after undergoing sleeve gastrectomy. At 12 months, testosterone had increased on average from 295 to 423 ng/dL. The normal range for circulating testosterone is 300 to 1000 ng/dL. A person is diagnosed with low serum testosterone when the level drops below 300 ng/dL.

Before the procedure, 63 percent of participants had low testosterone and afterwards, only 41 percent did. The average BMI was 46 before surgery and 31 after the operation. In addition, DHEA also rose, from 12.8 to 39.6 ng/mL, and serum PSA concentration rose over 12 months from 0.62 to 0.75 ng/mL with no change in PSA mass, which is a marker for prostate cancer progression.

[…]

“When you are obese, your fat becomes converted to estrogen, which will compete with testosterone and drive it down,” Dr. Morton said. “The nice thing about what this process does is it creates an autotransfusion of testosterone from yourself. This process occurs because you are losing weight, and therefore losing that estrogen, causing your natural testosterone stores to rise. It’s actually really helpful across the board for these patients.”

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Testosterone replacement therapy decreased respiratory hospitalizations by up to 9.1% in COPD patients. (2018) www.sciencedaily.com

Hormones Inflammation Testosterone

From the article:

“Previous studies have suggested that testosterone replacement therapy may have a positive effect on lung function in men with COPD [chronic obstructive pulmonary disease],” said Jacques Baillargeon, UTMB professor in preventive medicine and community health. “However, we are the first to conduct a large scale nationally representative study on this association.”

[…]

“We found that testosterone users had a greater decrease in respiratory hospitalizations compared with non-users. Specifically, middle-aged testosterone replacement therapy users had a 4.2 percent greater decrease in respiratory hospitalizations compared with non-users and older testosterone replacement therapy users had a 9.1 percent greater decrease in respiratory hospitalizations compared with non-users,” said Baillargeon. “The findings suggest that testosterone replacement therapy may slow the progression of disease in men with COPD.”

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For men, low testosterone may mean high risk of severe COVID-19, study suggests. (2021) www.sciencedaily.com

Hormones Testosterone COVID-19

From the article:

The researchers measured several hormones in blood samples from 90 men and 62 women who came to Barnes-Jewish Hospital with symptoms of COVID-19 and who had confirmed cases of the illness. For the 143 patients who were admitted to the hospital, the researchers measured hormone levels again at days 3, 7, 14 and 28, as long as the patients remained hospitalized over these time frames. In addition to testosterone, the investigators measured levels of estradiol, a form of estrogen produced by the body, and IGF-1, an important growth hormone that is similar to insulin and plays a role in maintaining muscle mass.

Among women, the researchers found no correlation between levels of any hormone and disease severity. Among men, only testosterone levels were linked to COVID-19 severity. A blood testosterone level of 250 nanograms per deciliter or less is considered low testosterone in adult men. At hospital admission, men with severe COVID-19 had average testosterone levels of 53 nanograms per deciliter; men with less severe disease had average levels of 151 nanograms per deciliter. By day three, the average testosterone level of the most severely ill men was only 19 nanograms per deciliter.

The lower the levels of testosterone, the more severe the disease. For example, those with the lowest levels of testosterone in the blood were at highest risk of going on a ventilator, needing intensive care or dying. Thirty-seven patients – 25 of whom were men – died over the course of the study.

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COVID-19 may deplete testosterone, helping to explain male patients' poorer prognosis. (2020) www.sciencedaily.com

Hormones Immune System Testosterone COVID-19

From the article:

“Testosterone is associated with the immune system of respiratory organs, and low levels of testosterone might increase the risk of respiratory infections. Low testosterone is also associated with infection-related hospitalisation and all-cause mortality in male in ICU patients, so testosterone treatment may also have benefits beyond improving outcomes for COVID-19,” Professor Çayan explains.

“In our study, the mean total testosterone decreased, as the severity of the COVID-19 increased. The mean total testosterone level was significantly lower in the ICU group than in the asymptomatic group. In addition, the mean total testosterone level was significantly lower in the ICU group than in the Intermediate Care Unit group. The mean serum follicle stimulating hormone level was significantly higher in the ICU group than in the asymptomatic group.

“We found, Hypogonadism – a condition in which the body doesn’t produce enough testosterone -in 113 (51.1%) of the male patients.

“The patients who died, had significantly lower mean total testosterone than the patients who were alive.

“However, even 65.2% of the 46 male patients who were asymptomatic had a loss of loss of libido.”

[…]

In the patients who had pre-COVID-19 serum gonadal hormones test (n: 24), serum total testosterone level significantly decreased from pre-COVID-19 level of 458±198 ng/dl to 315±12 ng/dl at the time of COVID-19 in the patients (p=0.003).

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Low testosterone may increase risk of COVID-19 hospitalization by 2.4-fold in men. (2022) www.sciencedaily.com

Hormones Testosterone COVID-19

From the article:

The team analyzed the cases of 723 men who tested positive for COVID-19, mostly in 2020 before vaccines were available. The data indicate that low testosterone is an independent risk factor for COVID-19 hospitalization, similar to diabetes, heart disease and chronic lung disease.

They found that men with low testosterone who developed COVID-19 were 2.4 times more likely to require hospitalization than men with hormone levels in the normal range. Further, men who were once diagnosed with low testosterone but successfully treated with hormone replacement therapy were no more likely to be hospitalized for COVID-19 than men whose testosterone levels had always tested in the normal range.

[…]

“Low testosterone turned out to be a risk factor for hospitalization from COVID, and treatment of low testosterone helped to negate that risk,” Dhindsa said. “The risk really takes off below a level of 200 nanograms per deciliter, with the normal range being 300 to 1,000 nanograms per deciliter. This is independent of all other risk factors that we looked at: age, obesity or other health conditions. But those people who were on therapy, their risk was normal.”

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Men's testosterone levels may be largely determined by where they grow up. (2018) www.sciencedaily.com

Hormones Testosterone Environment

From the article:

The study found that Bangladeshi men who grew up and lived as adults in the UK had significantly higher levels of testosterone compared to relatively well-off men who grew up and lived in Bangladesh as adults. Bangladeshis in Britain also reached puberty at a younger age and were taller than men who lived in Bangladesh throughout their childhood.

The researchers say the differences are linked to energy investment as it may only be possible to have high testosterone levels if there are not many other demands placed on the body such as fighting off infections. In environments where people are more exposed to disease or poor nutrition, developing males direct energy towards survival at the cost of testosterone.

The researchers collected data from 359 men on height, weight, age of puberty and other health information along with saliva samples to examine their testosterone levels. They compared the following groups: men born and still resident in Bangladesh; Bangladeshi men who moved to the UK (London) as children; Bangladeshi men who moved to the UK as adults; second-generation, UK-born men whose parents were Bangladeshi migrants; and UK-born ethnic Europeans.

Men with higher levels of testosterone are at greater risk of potentially adverse effects of this hormone on health and ageing. Very high levels can mean increased muscle mass, increased risk of prostate diseases and have been linked to higher aggression. Very low testosterone levels in men can include lack of energy, loss of libido and erectile dysfunction. The testosterone levels of the men in the study were, however, all in a range that would unlikely have an impact on their fertility.

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Testosterone treatment of older men didn`t affect functional status or cognition but increased lean body mass and had mixed metabolic effects. (2008) www.sciencedaily.com

Hormones Cholesterol Testosterone Muscle Bone Insulin Weight Loss Cardiovascular

From the article:

Marielle H. Emmelot-Vonk, M.D., of University Medical Center Utrecht, the Netherlands, and colleagues conducted a randomized, placebo-controlled study to assess the effects of testosterone supplementation on functional mobility, cognition, bone mineral density, body composition, lipids, quality of life, and safety parameters in older men with testosterone levels less than 13.7 nmol/L (less than the average level in this age group) during a period of six months. The trial, conducted from January 2004 to April 2005, included 207 men between the ages of 60 and 80 years. Participants were randomly assigned to receive 80 mg of testosterone undecenoate or a matching placebo twice daily for six months.

The researchers found that during the study, lean body mass increased and fat mass decreased in the testosterone group compared with the placebo group but these factors were not accompanied by an increase of functional mobility or muscle strength. Cognitive function and bone mineral density did not change. Insulin sensitivity improved but high-density lipoprotein cholesterol (the “good” cholesterol) decreased. By the end of the study, 47.8 percent in the testosterone group vs. 35.5 percent in the placebo group had the metabolic syndrome (a strong risk factor for cardiovascular disease and type 2 diabetes, a group of several metabolic components in one individual including obesity and dyslipidemia). This difference was not statistically significant.

Quality-of-life measures did not differ aside from hormone-related quality of life in the testosterone group. Adverse events were not significantly different in the two groups. Testosterone supplementation was associated with an increase in the concentrations of blood creatinine, a measure of kidney function, and hemoglobin and hematocrit, two red blood cell measures. No negative effects on prostate safety were detected (some reports have suggested that testosterone therapy could increase the risk of development or progression of prostate disease or cancer).

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Men with higher testosterone levels invested more money during a risky investment game. (2008) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

In the study, saliva samples were taken from 98 males, ages 18 to 23, who were mostly Harvard students. The samples were taken before participation in the investment game, so the researchers were certain that testosterone levels were not elevated as a result of the game. The researchers also assessed facial masculinity, associated with testosterone levels at puberty.

All of the participants were given $250, and were asked to choose an amount between $0 and $250 to invest. The participants kept the money that was not invested. A coin toss determined the investment’s outcome, and if the participant lost the coin toss, the money allocated to the investment was lost. However, if the coin toss was won, the participant would receive two and a half times the amount of their investment. At the end of the study, one person was selected by lottery to receive the cash amount of their investment, which created a monetary incentive for the participants.

The researchers found that a man whose testosterone levels were more than one standard deviation above the mean invested 12 percent more than the average man into the risky investment. A man with a facial masculinity score of one standard deviation higher than the mean invested 6 percent more than the average man.

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The beneficial effects of 6 months of testosterone treatment on frailty in older men were not maintained 6 months after treatment. (2010) www.sciencedaily.com

Aging Hormones Testosterone Muscle Weight Loss

From the article:

Frailty is an age-related state of physical limitation caused by the loss of muscle mass and function and can lead to adverse clinical outcomes such as dependency, institutionalization and death. Testosterone levels naturally decline with aging and testosterone replacement is a common therapy. Short-term testosterone treatment in frail elderly men has been shown to improve muscle mass and strength, but until now it has been unclear whether these effects could be maintained post-treatment.

[…]

In this study, researchers evaluated 274 intermediate-frail and frail elderly men aged 65-90 years with low testosterone levels. Study participants received either a testosterone gel or placebo for six months. Assessments were carried out at baseline, the end of treatment and six months after treatment cessation. Researchers found that the increased lean body mass, muscle strength and quality of life after six months of testosterone treatment were not maintained six months after treatment.

“At present, the optimal duration of anabolic hormonal intervention to produce sustained benefits in treating frailty in older men is unknown,” said Wu. “To best interrupt the downward spiral into frailty a greater emphasis should be placed on a multi-disciplinary interventional approach including resistance exercise, diet and other lifestyle options, in conjunction with pharmacological agents.”

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Low testosterone levels may be associated with risk of fracture in men over 60. (2008) www.sciencedaily.com

Hormones Testosterone Estrogen Bone

From the article:

Low-trauma fractures occurred in 113 men during follow-up with the risk of fracture significantly higher in those with low testosterone levels. “Twenty-five men experienced multiple incident fractures,” the authors note. “A total of 149 incident fractures were reported, including 55 vertebral, 27 hip, 28 rib, six wrist and 16 upper and 17 lower extremity fractures.”

“After adjustment for sex hormone binding globulin (a blood protein), serum testosterone and serum estradiol levels were associated with overall fracture risk,” according to the authors. “After further adjustment for major risk factors of fractures (age, weight or bone mineral density, fracture history, smoking status, calcium intake and sex hormone binding globulin), lower testosterone was still associated with increased risk of fracture, particularly with hip and non-vertebral fractures.”

Although low levels of estradiol and testosterone were associated with a higher risk of fracture in men over 60, only the effect of testosterone was independent of other risk factors, the authors conclude.

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Long-term testosterone treatment reduced weight by 36 pounds and waist circumference by 3.5 inches in men with low testosterone. (2012) www.sciencedaily.com

Hormones Testosterone Weight Loss

From the article:

The investigators restored testosterone to normal levels in 255 testosterone-deficient (“hypogonadal”) men, whose average age was nearly 61 (range, 38 to 83 years). Treatment lasted for up to five years, with injections given at day 1, after 6 weeks and then every 12 weeks after that. Patients did not follow a controlled diet or standard exercise program but received advice to improve their lifestyle habits.

On average, the men weighed 236 pounds before beginning testosterone treatment and 200 pounds after treatment (106.2 versus 90 kilograms), the authors reported. Weight loss was reportedly continuous, with an average reduction in body weight ranging from about 4 percent after one year of treatment to more than 13 percent after five years.

In addition, men lost an average of nearly 3.5 inches (8.8 centimeters) around their waist.

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High levels of free testosterone, but not total testosterone, may increase risk of prostate cancer. (2004) www.sciencedaily.com

Cancer Hormones Testosterone Prostate

From the article:

The researchers measured several forms of testosterone in almost 3,000 blood samples collected over a 40-year period from 759 men in the Baltimore Longitudinal Study on Aging, of whom 111 were diagnosed with prostate cancer. One form of testosterone, called free testosterone, which is biologically active and can actually be used by the prostate, was found to be associated with increased prostate cancer risk, according to J. Kellogg Parsons, M.D., instructor of urology at the Brady Urological Institute at Johns Hopkins and lead researcher of the study.

“Since testosterone replacement therapy increases the amount of free testosterone in the blood, older men considering or receiving testosterone replacement should be counseled as to the association until data from long-term clinical trials becomes available,” says Parsons.

The association between free testosterone and prostate cancer risk in older men was not affected by height, weight, percent of body fat, or muscle mass. Total testosterone levels and dehydroepiandrosterone sulfate (DHEAS), another androgenic hormone, were also unrelated to prostate cancer risk, while the protein that binds testosterone in blood, called sex hormone-binding globulin (SHBG), was associated with a slightly decreased risk for prostate cancer.

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Testosterone therapy reduced brain atrophy rate by 67% and improved cognition in men with multiple sclerosis. (2007) www.sciencedaily.com

Hormones Multiple Sclerosis Testosterone Neurodegeneration

From the article:

Nancy L. Sicotte, M.D., of the David Geffen School of Medicine at UCLA, Los Angeles, and colleagues conducted a study of testosterone treatment in 10 men with relapsing-remitting MS, characterized by periods of neurologic symptoms (such as numbness or difficulty walking) followed by periods of remission. The men, who had an average age of 46, were enrolled in the study and then entered a six-month pre-treatment phase, during which symptoms were monitored but no therapies were administered. Then, each man applied 10 grams of a gel containing 100 milligrams of testosterone to his upper arms once daily for 12 months.

“One year of treatment with testosterone gel was associated with improvement in cognitive performance and a slowing of brain atrophy [deterioration],” the authors write. During the first nine months of the study – the period of time before the men began taking testosterone, plus the first three months of treatment, before it had time to take effect – brain volume decreased an average of -0.81 percent per year.

In the second nine months, this decline slowed by 67 percent to an annual rate of -0.25 percent. “Because the protective effect of testosterone treatment on brain atrophy was observed in the absence of an appreciable anti-inflammatory effect, this protection may not be limited to MS, but may be applicable to those with non-inflammatory neurodegenerative diseases,” including amyotrophic lateral sclerosis or Lou Gehrig’s disease, the authors write.

In addition, lean body mass (muscle mass) increased an average of 1.7 kilograms (about 3.74 pounds) during the treatment phase. Participants did not report any adverse effects, there were no abnormalities in blood tests taken during the trial and the men’s prostate examination results remained stable.

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Obese teen boys showed up to 50 percent less testosterone than lean boys. (2012) www.sciencedaily.com

Obesity Hormones Sex Testosterone Weight Loss

From the article:

We were surprised to observe a 50 percent reduction in testosterone in this pediatric study because these obese males were young and were not diabetic,“ says Paresh Dandona, MD, PhD, SUNY Distinguished Professor in the Department of Medicine, chief of the Division of Endocrinology, Diabetes and Metabolism in the UB medical school and first author on the study. "The implications of our findings are, frankly, horrendous because these boys are potentially impotent and infertile,” says Dandona. “The message is a grim one with massive epidemiological implications.”

The small study included 25 obese and 25 lean males and was controlled for age and level of sexual maturity. Concentrations of total and free testosterone and estradiol, an estrogen hormone, were measured in morning fasting blood samples. The results need to be confirmed with a larger number of subjects, Dandona says.

[…]

“The good news is that we know that testosterone levels do return to normal in obese adult males who undergo gastric bypass surgery,” says Dandona. “It’s possible that levels also will return to normal through weight loss as a result of lifestyle change, although this needs to be confirmed by larger studies.”

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Testosterone may promote generosity in the absence of competition. (2013) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

To test this hypothesis, the researchers had 54 female volunteers ingest a liquid solution several hours before participating in an investing game – some volunteers received a placebo solution, while others received a solution with added testosterone.

In the investing game, participants were given €20 (about $27 USD) and were instructed that they could keep the amount they wanted and invest whatever remained with a trustee (another participant). The invested portion would be tripled and split by the trustee, who would keep whatever portion she wanted and return the rest to the investor.

If participants were completely trusting, they could invest all €20 and hope that the trustee would split the final €60 equally. If they wanted to play it safe, they could keep the €20 for themselves.

Each participant took turns playing both investor and trustee. When they were the trustee, they were always given €60, indicating that the investor had entrusted them with the task of splitting up the whole sum.

As investors, participants who received testosterone were, on average, stingier – they placed less trust in the trustee and kept more of their initial money. Participants who received the placebo, on the other hand, were more trusting investors, choosing to invest about €3.20 more than those who received testosterone.

Just as the researchers predicted, testosterone seemed to promote antisocial behavior in response to a potential threat – in this case, a threat to financial resources.

But the opposite effect emerged when participants played the role of trustee. In this case, participants given testosterone chose to give more money back to the investor than participants who had been given a placebo. The results suggest that the trustees felt a responsibility to repay the trust that the investor ostensibly placed in them.

“While we expected the decrease in trust found in the first scenario, the increase in reciprocity was surprisingly strong and robust,” Boksem notes. “Testosterone had a more pronounced effect on prosocial behavior than on antisocial behavior.”

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Testosterone therapy reduced the risk of death from 20% to 8.6% in type 2 diabetes patients with low testosterone. (2011) www.sciencedaily.com

Hormones Diabetes Testosterone Mortality

From the article:

Professor Jones' team conducted a six year study of 587 men with type 2 diabetes, splitting them into three groups: those with normal total testosterone levels (above 10.4nmol/L, n=338), those with low testosterone levels (below 10.4nmol/L) that weren’t treated with testosterone replacement therapy (n=182), and those with low testosterone levels treated with testosterone replacement therapy for two years or more during the follow up period (n=58).

The findings show for the first time that low testosterone puts diabetic men at a significantly increased risk of death (p=0.001 log rank): 36 of the 182 diabetic men with untreated low testosterone died during the six year study, compared to 31 of the 338 men with normal testosterone levels (20% vs 9%). Furthermore, only 5 of the 58 diabetic men that were given testosterone replacement therapy died during the study (8.6%), meaning they showed significantly better survival compared to the non-treated group (p=0.049 log rank).

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In older men with low testosterone levels, testosterone replacement therapy improved risk factors for cardiovascular disease and diabetes. (2008) www.sciencedaily.com

Hormones Diabetes Cholesterol Testosterone Triglycerides Metabolic Syndrome Weight Loss Cardiovascular

From the article:

All 95 men in the studies (ages 34 to 69 years) had the metabolic syndrome. To receive this diagnosis, patients must have three of the following five risk factors: increased waist circumference (abdominal fat), low HDL (“good”) cholesterol, high triglycerides (fats in the blood), high blood pressure, and high blood sugar.

The first study showed that testosterone treatment significantly reduced waist circumference, total cholesterol, LDL (“bad”) cholesterol, triglycerides, and body mass index (a measure of body fat). Treatment also increased “good” cholesterol. Improvements were progressive over 12 months, indicating that benefits may continue past a year, Saad said.

In the second study, the researchers divided the patient population into three groups by age: less than 57 years, 57 to 63 years, and more than 63 years. They found that the oldest men had similar improvements in metabolic risk factors to the youngest men.

Additionally, the investigators looked at the degree of testosterone deficiency before treatment. This beginning level of testosterone deficiency did not predict the beneficial outcome, they found. Men whose subnormal testosterone levels were not as low as the others had similar improvements in metabolic risk factors to men with the lowest levels, according to Saad.

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Continuous testosterone administration for 5 months reduced markers of bone turnover in older men with low-to-normal testosterone levels. (2008) www.sciencedaily.com

Hormones Testosterone Bone

From the article:

Thirteen older men between 60 – 85 years have thusfar participated in the study. Testosterone levels ranged between 200-500 nanograms (ng) of testosterone per deciliter of blood (dL) at the time of enrollment. (Normal limits are considered 250-800.) Each was enrolled in one of three double-blinded groups: (1) those receiving continuous weekly intramuscular injections of testosterone (100 mg testosterone-enanthate) for the entire five month period (TE; n=4); (2) those receiving weekly testosterone every other month (one month of weekly testosterone/one month of weekly placebo; MO; n=4); or (3) those receiving a weekly placebo for the entire five month period (PL; n=5).

The participants visited the clinic weekly for either scheduled treatment injections or placebos. Volunteers received a baseline whole-body Dual Energy X-Ray Absorptiometry (DEXA) scan at the beginning and end of the study. Dietary records were obtained and analyzed at month zero, month three and month five. Fasting blood samples were collected at regular intervals throughout the study to examine serum markers of bone metabolism.

Preliminary Study Results

– testosterone administration appears to reduce bone turnover, perhaps closing the gap between resorption and formation

– thus far, the impact on bone mineral density are unclear but may become more apparent as the study progresses.

– the effects of testosterone on long-term bone metabolism are unclear, but are expected to have at least a protective effect on existing bone mass over time by preventing unwanted increases in bone turnover that are frequently associated with osteoporosis. Osteoporosis is often associated with high bone turnover (increases in bone resorption as well as in bone formation) which results in decreased BMD.

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Testosterone deprivation therapy in men may be associated with a loss of memory consolidation. (2004) www.sciencedaily.com

Brain Hormones Memory Testosterone

From the article:

“A colleague looked at (the study results) and said, ‘Wow, that looks exactly like what happens with a lesion in the hippocampus,’” Janowsky said. “When others have done studies like this on people who have hippocampal damage from early Alzheimer’s disease or lesions due to strokes, this is the pattern.”

The study examined 30 individuals - 14 men undergoing androgen deprivation treatment for prostate cancer and 16 healthy, age-matched men - from the Portland area. Participants were shown lists of words and, to encode them, were asked to identify whether the words were in capital or lowercase letters, which requires shallow or “perceptual” processing, or whether they represented objects that occurred in nature or were artificially made, which requires deep or “semantic” processing.

Participants were then shown another list containing words they’d just seen as well as new words and were asked whether they’d seen each word before. This test was performed at three time intervals: immediately, after two minutes and after 12 minutes.

Testosterone-deprived men can “immediately get the information in, but then the hippocampus can’t consolidate it and send it off for storage,” Janowsky said. “When you look at their memory, they’re perfectly normal when they’re immediately asked to recall something, but they can’t hold or save the information as well in order to recall it over a retention interval, over a period of time. They’re faster at forgetting.”

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Testosterone may mediate antidepressant effects via ERK2 signaling, rat study suggests. (2012) www.sciencedaily.com

Hormones Depression Mental Health Testosterone Neurogenesis

From the article:

Compared to men, women are twice as likely to suffer from an affective disorder like depression. Men with hypogonadism, a condition where the body produces no or low testosterone, also suffer increased levels of depression and anxiety. Testosterone replacement therapy has been shown to effectively improve mood.

Although it may seem that much is already known, it is of vital importance to fully characterize how and where these effects are occurring so that scientists can better target the development of future antidepressant therapies.

To advance this goal, the scientists performed multiple experiments in neutered adult male rats. The rats developed depressive-like behaviors that were reversed with testosterone replacement.

They also “identified a molecular pathway called MAPK/ERK2 (mitogen activated protein kinase/ extracellular regulated kinase 2) in the hippocampus that plays a major role in mediating the protective effects of testosterone,” said Kabbaj.

This suggests that the proper functioning of ERK2 is necessary before the antidepressant effects of testosterone can occur. It also suggests that this pathway may be a promising target for antidepressant therapies.

Kabbaj added, “Interestingly, the beneficial effects of testosterone were not associated with changes in neurogenesis (generation of new neurons) in the hippocampus as it is the case with other classical antidepressants like imipramine (Tofranil) and fluoxetine (Prozac).”

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Testosterone therapy following angiography may be linked with increased risk of adverse outcomes. (2013) www.sciencedaily.com

Hormones Heart Disease Testosterone Cardiovascular

From the article:

Rebecca Vigen, M.D., M.S.C.S., of the University of Texas at Southwestern Medical Center, Dallas and colleagues evaluated the association between the use of testosterone therapy and all-cause mortality, myocardial infarction (MI; heart attack), and stroke among male veterans and whether this association was modified by underlying coronary artery disease (CAD). The study included 8,709 men with low testosterone levels (<300 ng/dL) who underwent coronary angiography in the Veterans Affairs (VA) system between 2005 and 2011. There was a high level of co-existing illnesses among this group, including prior history of heart attack, diabetes, or CAD. Of the 8,709 patients, 1,223 (14.0 percent) initiated testosterone therapy after a median (midpoint) of 531 days following angiography. The average follow-up was approximately 2 years, 3.5 months. The primary measured outcome for the study was a composite of all-cause mortality, heart attack, and ischemic stroke.

The researchers found that the proportion of patients experiencing events 3 years after coronary angiography was 19.9 percent in the no testosterone therapy group (average age, 64 years) and 25.7 percent in the testosterone therapy group (average age, 61 years), for an absolute risk difference of 5.8 percent. Even accounting for other factors that could explain the differences, use of testosterone therapy was associated with adverse outcomes and was consistent among patients with and without CAD. The increased risk of adverse outcomes associated with testosterone therapy use was not related to differences in risk factor control or rates of secondary prevention medication use because patients in both groups had similar blood pressure, low-density lipoprotein levels, and use of secondary prevention medications.

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Amazonian forager-horticulturalists have lower testosterone levels than U.S. men, but show short-term testosterone spikes during competition. (2012) www.sciencedaily.com

Exercise Hormones Immune System Testosterone

From the article:

But new research shows that Tsimane (“chi-MAH-nay”) men have a third less baseline testosterone compared with men living in the United States, where life is less physically demanding. And unlike men in the U.S., the Bolivian foragers-farmers do not show declines in testosterone with age.

“Maintaining high levels of testosterone compromises the immune system, so it makes sense to keep it low in environments where parasites and pathogens are rampant, as they are where the Tsimane live,” said Ben Trumble, an anthropology graduate student at the University of Washington.

That men living in the U.S. have greater circulating levels of testosterone represents an “evolutionarily novel spike,” Trumble said. The spike reflects how low levels of pathogens and parasites in the U.S. and other industrialized countries allow men to maintain higher testosterone without risking infection.

[…]

Despite lower circulating levels of testosterone under normal conditions, the forager-farmers do have something in common with U.S. men: short-term spikes of testosterone during competition.

Trumble and his co-authors organized a soccer tournament for eight Tsimane teams. The researchers found that Tsimane men had a 30 percent increase in testosterone immediately after a soccer game. An hour after the game, testosterone was still 15 percent higher than under normal conditions. Similar percent increases have been shown in men living in the U.S. or other industrialized nations following sports competitions.

[…]

“What’s interesting is that in spite of being in a more pathogenic environment, it’s still important to raise testosterone for short-term bursts of energy and competition,” said Michael Gurven, co-author and anthropology professor at the University of California Santa Barbara.

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Older men with higher testosterone levels may lose less muscle mass as they age. (2011) www.sciencedaily.com

Aging Hormones Testosterone Muscle

From the article:

“Our study finds that men, aged 65 years and older, with higher testosterone levels lost less muscle mass, especially in their arms and legs, than men this age who had lower testosterone levels,” said Erin LeBlanc, MD, of Kaiser Permanente Northwest in Portland, OR and lead author of the study. “Men who had higher testosterone levels before they lost weight also lost less leg function and could stand up more easily from a chair than men who had lower testosterone levels before they lost weight.”

In this study, researchers used data from 1,183 men aged 65 years or older and tested the hypothesis that higher baseline measures of sex steroids are associated with lesser declines in lean mass and maintenance of physical performance over an average follow-up of 4.5 years. Body composition was measured using dual energy x-ray absorptiometry (DXA) scans and physical performance was measured through a series of exercises that assessed grip strength, lower extremity power, walking speed and the ability to rise from a chair without the use of arms.

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Elevated testosterone induces apoptosis in neuronal cells, cell study suggests. (2006) www.sciencedaily.com

Brain Alzheimer's Hormones Testosterone Apoptosis Neurons Neurodegeneration

From the article:

The researchers showed that high levels of testosterone triggered programmed cell death in nerve cells in culture. Cell death, or apoptosis, is critical in many life processes, including development and disease. It is characterized by membrane instability, activation of caspases, which are the executioner proteins in apoptosis, change in membrane potential, and DNA fragmentation.

“In the present study we have demonstrated for the first time that the treatment of neuroblastoma cells with elevated concentrations of testosterone for relatively short periods, six to 12 hours, induces a decrease in cell viability by activation of a cell death program,” Ehrlich said. “Low concentrations of testosterone had no effects on cell viability, whereas at high concentrations the cell viability decreased with incremental increases in hormone concentration.”

The testosterone-induced apoptosis described in this study occurs through overactivation of intracellular Ca2+ signaling pathways. Overstimulation of the apoptotic program in neurons has been associated with several neurological illnesses, such as Alzheimer disease and Huntington disease.

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Testosterone-replacement therapy reduced the prevalence of metabolic syndrome in patients with low testosterone from 56% to 30%. (2012) www.sciencedaily.com

Hormones Testosterone Triglycerides Blood Pressure Blood Sugar Weight Loss

From the article:

“When indicated, testosterone treatment is both essential and safe in elderly patients with symptomatic late onset hypogonadism, or testosterone deficiency,” said study lead author Aksam A. Yassin, M.D., Ph.D., Ed.D., chairman of the Institute of Urology & Andrology in Norderstedt-Hamburg, Germany. “Further analysis is needed to confirm if our findings are due to a direct effect of restoring physiologic testosterone levels.”

Specifically, investigators found that the prevalence of metabolic syndrome dropped from 56 to 30 percent after 57 months of treatment with testosterone-replacement medication to regulate hormone levels. In addition, triglycerides, and levels of blood sugar and pressure significantly decreased, while the average waist circumference shrank by 11 centimeters.

Beginning in 2004, investigators collected data from 261 patients with late-onset hypogonadism, characterized by both low testosterone levels and sexual dysfunction, at three centers in Germany. Patients received 1,000 milligrams of a long-acting testosterone drug, called undecanoate, on the first day of the study, at week six, and then every three months.

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Testosterone may protect against inflammation by reducing phospholipase D activity in immune cells, cell study suggests. (2011) www.sciencedaily.com

Hormones Inflammation Immune System Testosterone Cardiovascular

From the publication:

“In a series of analyses we have shown that cells from men and women react in a different manner to inflammatory stimuli,” Dr. Carlo Pergola from the Institute of Pharmacy of University Jena explains. Thus, certain immune cells of women produced nearly twice as many pro-inflammatory substances than those of men. Together with colleagues from Tübingen (Germany), Stockholm (Sweden) and Naples (Italy) the Jena researchers pursued the molecular basis for these differences and published their findings in their current study. To this aim, they isolated immune cells of male and female donors and analyzed in test tubes the activity of the enzymes responsible for the production of pro-inflammatory substances. They found that in male cells the enzyme phospholipase D is less active than in the female ones. “Interestingly, the activity of the enzyme is reduced after treatment with testosterone also in the female immune cells“, Dr. Pergola defines a crucial result.

Based on these findings, the Jena pharmacists concluded that the male sex hormones play a key role in the modulation of the immune response. This would also explain another phenomenon that has been previously noticed, that is, testosterone can protect men from arteriosclerosis.

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Diabetic men with low testosterone had a sixfold higher risk of increased carotid artery thickness and endothelial dysfunction. (2014) www.sciencedaily.com

Hormones Diabetes Testosterone Cardiovascular

From the publication:

The cross-sectional prospective study published in JCEM examined testosterone levels and key atherosclerotic markers, including intimal media thickening of the layers in the carotid artery, the presence of atherosclerotic plaques, function of the endothelial cells that line the heart and blood vessels, and inflammatory markers in 115 men with Type 2 diabetes. The participants were younger than age 70 and had no history of cardiovascular disease. Researchers measured the levels of testosterone in each participant’s blood. Among the participants, more than half of patients with diabetes were found to have low testosterone levels.

The study found men who had low testosterone and Type 2 diabetes were six times more likely to have increased thickness of the carotid artery and endothelium dysfunction compared to men with normal serum testosterone levels. A total of 54 percent of the men with low testosterone and 10 percent of the men with normal testosterone were found to be at higher risk for vascular disease.

“We still need to determine whether testosterone is directly involved in the development of atherosclerosis or if it is merely an indicator of advanced disease,” Farias said.

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Long-term testosterone therapy in hypogonadal men does not increase the risk of prostate cancer, study suggests. (2014) www.sciencedaily.com

Cancer Hormones Testosterone Prostate

From the article:

A total of 1,023 patients on T[estosterone] therapy were followed for up to 17 years with a median follow-up of approximately 5 years. Two study cohorts of 261 (cohort 1) and 340 (cohort 2) men were treated by urologists since 2004 and a third cohort of 422 men was treated at an academic andrology center since 1996. Hypogonadism was diagnosed if testosterone was ≤12 nmol/L [345.82 ng/dL] and if other symptoms were present, such as erectile dysfunction, fatigue, depression, or unfavorable changes in body composition (gaining of fat mass and waist circumference despite physical activity). If no contraindications were present, all were started on T therapy.

There were six (2.3%) diagnoses of PCa [prostate cancer] in cohort 1, there were five (1.5%) diagnoses of PCa in cohort 2, and all biopsies were negative in cohort 3. PCa incidence per 10,000 patient-years in cohorts 1 and 2 was 54.4 and 30.7, respectively, which is lower than 116 reported by the PLCO (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial) and 96.6 reported by the ERSPC ( European Randomized Study of Screening for Prostate Cancer).

Investigators stress that if guidelines for T therapy are properly applied, it is safe in hypogonadal men.

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Low testosterone levels may be common and associated with insulin resistance in men with diabetes. (2008) www.sciencedaily.com

Hormones Diabetes Testosterone

From the article:

For this study, researchers conducted a survey of 580 men with type 2 diabetes and 69 men with type 1 diabetes. A subgroup of 262 men with type 2 diabetes was then reassessed after six months. Testosterone levels were measured from blood samples using the Access testosterone assay.

Previous population-studies found an association of reduced testosterone levels in men and type 2 diabetes, however this is the first study to demonstrate a similar prevalence in individuals with type 1 diabetes.

This study raises the question of whether testosterone replacement therapy can reduce insulin resistance or symptoms of hypogonadism in men with diabetes. Researchers, however stress that the balance of benefits and risks of such treatment is currently unknown and still to be defined by large and long-term clinical trials. Also, while insulin resistance is associated with testosterone deficiency, there is no evidence that insulin sensitizers are able to elevate testosterone levels in men with diabetes.

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In overweight and obese men, higher testosterone levels may be associated with poorer sleep quality. (2014) www.sciencedaily.com

Obesity Sleep Hormones Testosterone

From the publication:

The research team performed a polysomnogram, or overnight sleep study, in 44 men ages 20 to 50 years who were overweight or obese. All subjects were otherwise healthy and were nonsmokers. Their selection for the study did not consider whether they had symptoms or a history of sleep apnea, according to Van Cauter. However, the sleep study showed that 29 (66 percent) of the men did have OSA [obstructive sleep apnea], which she said was moderately severe in most cases.

[…]

Later analyses demonstrated that higher total testosterone level strongly correlated with more shallow sleep. This association, Van Cauter said, was independent from the presence of other factors known to decrease sleep quality, such as age, race/ethnicity and OSA [obstructive sleep apnea] severity.

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Single dose of testosterone significantly increased fair negotiation behavior in women. (2009) www.sciencedaily.com

Hormones Behavior Testosterone

From the publication:

For the study, published in the journal Nature, some 120 test subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything.

[…]

Fairer with testosterone

The study’s results, however, contradict this view sharply. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. “The preconception that testosterone only causes aggressive or egoistic behavior in humans is thus clearly refuted,” sums up Eisenegger. Instead, the findings suggest that the hormone increases the sensitivity for status. For animal species with relatively simple social systems, an increased awareness for status may express itself in aggressiveness. “In the socially complex human environment, pro-social behavior secures status, and not aggression,” surmises study co-author Michael Naef from Royal Holloway London. “The interplay between testosterone and the socially differentiated environment of humans, and not testosterone itself, probably causes fair or aggressive behavior.”

Moreover the study shows that the popular wisdom that the hormone causes aggression is apparently deeply entrenched: those test subjects who believed they had received the testosterone compound and not the placebo stood out with their conspicuously unfair offers. It is possible that these persons exploited the popular wisdom to legitimate their unfair actions. Economist Michael Naef states: “It appears that it is not testosterone itself that induces aggressiveness, but rather the myth surrounding the hormone.”

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Testosterone may increase honesty in men. (2012) www.sciencedaily.com

Hormones Behavior Testosterone

From the publication:

This was followed by the behavioral experiments. The test subjects played a simple game of dice in separate booths. The higher their scores, the higher the amounts of money they received as a reward. “These experiments were designed such that the test subjects were able to lie,” reports Prof. Weber. “Due to the separate booths, nobody knew whether they were entering their real scores into the computer, or higher ones in order to get more money.” However, the scientists were able to determine later whether the various test subjects had cheated or not. “Statistically, the probability for all numbers on the dice to occur is identical,” explains the neuroscientist. “So, if there are outliers in the higher numbers, this is a clear indication that subjects have been cheating.”

Test subjects with higher testosterone levels lied less

The researchers compared the results from the testosterone group to those from the control group. “This showed that the test subjects with the higher testosterone levels had clearly lied less frequently than untreated test subjects,” reports the economist Prof. Dr. Armin Falk, who is one of the CENS co-directors with Prof. Weber. “This result clearly contradicts the one-dimensional approach that testosterone results in anti-social behavior.” He added that it is likely that the hormone increases pride and the need to develop a positive self-image. “Against this background, a few euros are obviously not a sufficient incentive to jeopardize one’s feeling of self-worth,” Prof. Falk reckons.

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Sleep quantity may affect morning testosterone levels in older men. (2007) www.sciencedaily.com

Sleep Hormones Testosterone

From the publication:

The study, conducted by Plamen Penev, MD, PhD, of the University of Chicago, focused on 12 healthy men between the ages of 64 and 74. Three morning blood samples were pooled for the measurement of total and free testosterone. In addition to overnight laboratory polysomnography, wrist activity monitoring for six-to-nine days were used to determine the amount of nighttime sleep of the participants in everyday life settings.

The main outcome levels were total sleep time and morning testosterone levels. Analyses revealed that the amount of nighttime sleep measured by polysomnography was an independent predictor of the subjects' morning total and free testosterone levels.

“The results of the study raise the possibility that older men who obtain less actual sleep during the night have lower blood testosterone levels in the morning,” said Penev. “Although the findings suggest that how long a person sleeps may be an indicator of age-related changes in important hormone signals in the body, future studies are needed to determine the importance of these relationships for the health of older adults.”

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Weight loss reduced the prevalence of low testosterone levels in overweight, middle-aged men with prediabetes by 46%. (2012) www.sciencedaily.com

Obesity Hormones Diabetes Testosterone Weight Loss

From the article:

The study population had 891 middle-aged men, with an average age of 54 years. The men were randomly assigned to receive one of three treatments: 293 men to lifestyle modification, 305 to the diabetes drug metformin and 293 to inactive placebo pills. Lifestyle modifications consisted of exercising for 150 minutes a week and eating less fat and fewer calories.

The results showed that low testosterone levels are common in overweight men with prediabetes, Hayes said. At the beginning of the study, nearly one in four men had low testosterone levels, considered to be below 300 nanograms per deciliter.

With lifestyle modification, the prevalence of low testosterone levels decreased from about 20 percent to 11 percent after one year, a 46 percent decrease, the authors reported. The prevalence of low testosterone was unchanged in the metformin group (24.8 versus 23.8 percent) and the placebo group (25.6 versus 24.6 percent).

Men in the lifestyle modification group lost an average of about 17 pounds (7.8 kilograms) over the one-year study, according to the abstract. The increase in testosterone levels in that group correlated with decreasing body weight and waist size.

“Losing weight not only reduces the risk of prediabetic men progressing to diabetes but also appears to increase their body’s production of testosterone,” Hayes said.

Men may have a 2.5-fold increased 10-year risk of death if they have low testosterone, regardless of age. (2008) www.sciencedaily.com

Cancer Hormones Heart Disease Testosterone Mortality Cardiovascular

From the publication:

In the study, Haring and co-workers looked at death from any cause in nearly 2,000 men aged 20 to 79 years who were living in northeast Germany and who participated in the Study of Health in Pomerania (SHIP). Follow-up averaged 7 years. At the beginning of the study, 5 percent of these men had low blood testosterone levels, defined as the lower end of the normal range for young adult men. The men with low testosterone were older, more obese, and had a greater prevalence of diabetes and high blood pressure, compared with men who had higher testosterone levels, Haring said.

Men with low testosterone levels had more than 2.5 times greater risk of dying during the next 10 years compared to men with higher testosterone, the study found. This difference was not explained by age, smoking, alcohol intake, level of physical activity, or increased waist circumference (a risk factor for diabetes and heart disease), Haring said.

In cause-specific death analyses, low testosterone predicted increased risk of death due to cardiovascular disease and cancer but not death of any other single cause.

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Low levels of testosterone may increase long-term risk of death by 33% in men over 50 years old. (2007) www.sciencedaily.com

Hormones Inflammation Testosterone Mortality Metabolic Syndrome

From the publication:

In the study, Laughlin and co-workers looked at death, no matter the cause, in nearly 800 men, ages 50 to 91 years, who were living in Rancho Bernardo, California. The participants have been members of the Rancho Bernardo Heart and Chronic Disease Study since the 1970s. At the beginning of the 1980s, almost one-third of these men had suboptimal blood testosterone levels for men their age.

The group with low testosterone levels had a 33 percent greater risk of death during the next 18 years than the men with higher testosterone. This difference was not explained by smoking, drinking, physical activity level or pre-existing diseases (such as diabetes or heart disease).

In this study, “low testosterone” levels were set at the lower limit of the normal range for young adult men. Testosterone declines slowly with aging in men and levels vary widely, with many older men still having testosterone levels in the range of young men. Twenty-nine percent of Rancho Bernardo men had low testosterone.

Distinguishing Factors

Men with low testosterone were more likely to have elevated markers of inflammation, called inflammatory cytokines, which contribute to many diseases. Another characteristic that distinguished the men with low testosterone was a larger waist girth along with a cluster of cardiovascular and diabetes risk factors related to this type of fat accumulation. Men with low testosterone are three times more likely to have the metabolic syndrome than men with higher testosterone levels;

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Low testosterone levels may herald rheumatoid arthritis in men. (2013) www.sciencedaily.com

Obesity Hormones Inflammation Testosterone Tobacco Arthritis

From the article:

Sex hormones are thought to play a part in the development of rheumatoid arthritis, and both men and women with the condition tend to have lower levels of testosterone in their blood than healthy people. But it is not clear whether this is a contributory factor or a consequence of the disease.

The researchers based their findings on participants of the Swedish Malmo Preventive Medicine Program (MPMP), which began in 1974 and tracked the health of more than 33,000 people born between 1921 and 1949.

[…]

After taking account of smoking and body mass index, both of which can affect the risk of rheumatoid arthritis, **men with lower levels of testosterone in their blood samples were more likely to develop the disease.

This was **statistically significant for those who tested negative for rheumatoid factor when they were diagnosed.

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Cigarette smoking may negate the protective effect of normalizing testosterone levels on all-cause mortality and myocardial infarction. (2018) doi.org

Hormones Heart Disease Testosterone Tobacco Cardiovascular

From the publication:

Data from 18,055 males with known CS status and low TT levels who received TRT at the Veterans Health Administration between December 1, 1999, and May 31, 2014, were grouped into (1) current smokers with normalized TT, (2) current smokers with nonnormalized TT, (3) nonsmokers with normalized TT, and (4) nonsmokers with nonnormalized TT.

[…]

Our findings show that maintaining normal levels of testosterone in testosterone-deficient nonsmokers reduces all-cause mortality and MI [myocardial infarction]. Cigarette smoking negates the beneficial effects of testosterone level normalization after TRT on MI and all-cause mortality. Adequately powered randomized clinical trials would be needed for conclusive determination of the effects of CS [cigarette smoking] and TRT [testosterone replacement therapy ] on CV [cardiovascular] risk and mortality. However, conducting such a randomized clinical trial in the United States would be prohibitive because smoking is an established risk factor for CVD. Based on the present study, counseling and treatment for smoking cessation would be an important intervention before and during TRT. Acknowledging the limitations of a retrospective analysis, results presented in the article provide insight and information that may be valuable in clinical practice.

Low testosterone levels may be linked to a twofold risk of premature death from heart disease and all causes. (2010) www.sciencedaily.com

Hormones Heart Disease Testosterone Blood Pressure

From the publication:

The researchers base their findings on 930 men, all of whom had coronary artery heart disease, and had been referred to a specialist heart centre between 2000 and 2002. Their heart health was then tracked for around 7 years.

On referral, low testosterone was relatively common. One in four of the men was classified as having low testosterone, using measurements of either bioavailable testosterone (bio-T) – available for tissues to use – of under 2.6 mmol/l [74.9 ng/dL] or total testosterone (TT) of under 8.1 mmol/l [233.4 ng/dL]

These measures indicate clinically defined testosterone deficiency, referred to as hypogonadism, as opposed to a tailing off in levels of the hormone as a result of ageing.

During the monitoring period almost twice as many men with low testosterone died as did those with normal levels. One in five (41) of those with low testosterone died, compared with one in eight (12%) of those with normal levels.

The only factors that influenced this risk were heart failure (left ventricular dysfunction), treatment with aspirin or a high blood pressure drug (beta blocker) and low bio-T levels.

A low bio-T level was an independent risk factor for premature death from all causes and from heart disease, after taking account of other influential factors, such as age, other underlying health problems, smoking and weight.

Borderline levels of low total testosterone (15.1mmol/l) [435.1 ng/dL] also increased the risk of an early death.

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Meta-analysis of clinical trials did not find any evidence to support beneficial effect of vitamin D supplementation on testosterone levels. (2019) doi.org

Vitamin D Hormones Testosterone

From the publication:

In this systematic review and meta‐analysis of RCTs, vitamin D supplementation had no significant effect on TT [total testosterone] and SHBG in men. In term of intervention, treatment duration (<16 or ≥16 weeks), type of prescription (weekly or daily), daily doses of vitamin D supplementation (<3,000 IU/day or ≥ 3,000 IU/day) and baseline 25(OH)D [40 nmol/L or lower or higher than 40 nmol/L] and TT [total testosterone] levels confirmed the null finding in total analysis. Our results are consistent with the current systematic review (Trummeret al., 2018), which found conflicting results about the effect of vitamin D supplementation on TT in men in RCTs and observa‐tional studies.

[…]

The main outcome of this study reaffirmed the null effect of vitamin D supplementation on TT and SHBG in men. To solve this problem in the future, we recommend further studies that consider the effect of vitamin D over a longer period in men with hypogonadism and severe vitamin D deficiency.

Claimed associations between vitamin D deficiency and low testosterone could reflect nonbiological correlations, meta-analysis suggests. (2021) onlinelibrary.wiley.com

Vitamin D Hormones Testosterone

From the publication:

Eligibility criteria for the study selection were (i) observational case-control studies involving men with 25(OH)D <20 ng/mL (cases) and ≥20 ng/mL (controls) (ii) availability of mean ± standard deviation (SD) of total testosterone levels in both groups.

[…]

Overall, at the pooled estimate of eighteen carefully selected case-control studies, vitamin D deficiency was associated with a slight, albeit just significant, decrease in circulating total testosterone levels but the result was burdened with a large between‑study heterogeneity. Noteworthy, when studies were grouped according to health-related characteristics of the populations under investigation, a significant positive association between 25(OH)D and testosterone levels, along with a noticeable decrease in heterogeneity, could only be demonstrated in studies of patients with frailty states, including men with advanced age and/or documented chronic comorbidities. This indicated that the significant association arising from the overall analysis reflected the inclusion of studies on frail series. In the sub-group of studies carried out in ‘non-frail’ populations, besides the loss of the statistical significance in the association between lower 25(OH)D and lower testosterone, a large between-study heterogeneity persisted. […] Taken together these data suggest that the claimed association between vitamin D deficiency and low testosterone could reflect nonbiological correlations due to similar distributions of shared risk factors and confounders.

[…]

Further studies are warranted to elucidate a possible direct clinical contribution of Leydig cell dysfunction to vitamin D deficiency in men with frailty states related to chronic illnesses.

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Creatine supplementation (10 weeks) increased testosterone levels in collegiate football players. (2006) pubmed.ncbi.nlm.nih.gov

Exercise Hormones Testosterone Weight Loss Supplements

From the publication:

The effects of creatine and creatine plus β-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine ( C), or creatine plus β-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C [creatine group], however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus β-alanine on strength performance. Creatine plus β-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.

Short-term creatine supplementation increased sprint performance and testosterone levels by at least 15% in male amateur swimmers. (2011) www.sciencedirect.com

Exercise Hormones Testosterone Supplements

From the publication:

Twenty amateur male swimmers ingested creatine monohydrate (CR) or a matched placebo (PL) for 6 days. All subjects performed 6 days, swimming exercise. The subjects were tested for performance and hormonal responses the day before and after this creatine loading.

Results. — The mean swimming time of CR group in 50 m was significantly decreased (Beforeperiod: 53.1 ± 3.73 s, after-period: 50.7 ± 2.84 s). Growth hormone and cortisol were not affected by this creatine loading. But, testosterone concentration was significantly greater in CR compared to PL after supplementation period (P < 0.05).

Conclusions. — Our data suggest that short-term creatine supplementation has improved 50 m sprint performance in amateur swimmer and it seems unlikely creatine loading is hormonally mediated.

In overweight men with vitamin D deficiency, testosterone levels increased significantly after taking 3320 IU of vitamin D daily for one year. (2011) pubmed.ncbi.nlm.nih.gov

Vitamin D Obesity Hormones Testosterone

From the publication:

Healthy overweight men undergoing a weight reduction program who participated in a randomized controlled trial were analyzed for testosterone levels. The entire study included 200 nondiabetic subjects, of whom 165 participants (54 men) completed the trial. Participants received either 83 μg (3,332 IU) vitamin D daily for 1 year (n = 31) or placebo (n =2 3). Initial 25(OH)D concentrations were in the deficiency range (< 50 nmol/l) and testosterone values were at the lower end of the reference range (9.09-55.28 nmol/l for males aged 20-49 years) in both groups. Mean circulating 25(OH)D concentrations increased significantly by 53.5 nmol/l in the vitamin D group, but remained almost constant in the placebo group. Compared to baseline values, a significant increase in total testosterone levels (from 10.7 ± 3.9 nmol/l to 13.4 ± 4.7 nmol/l; p < 0.001), bioactive testosterone (from 5.21 ± 1.87 nmol/l to 6.25 ± 2.01 nmol/l; p = 0.001), and free testosterone levels (from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l; p = 0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group. Our results suggest that vitamin D supplementation might increase testosterone levels. Further randomized controlled trials are warranted to confirm this hypothesis.

Cancer Hormones Heart Disease Testosterone Prostate Stroke Cardiovascular

From the publication

The purpose of this paper is to analyze the guidelines for TTh [testosterone therapy] from international organizations and compare their recommendations.

[…]

All agree that TD [testosterone deficiency] is a clinical syndrome that requires a low testosterone level as well as signs and/or symptoms for a diagnosis to be made. The exact cut -off varies or is not provided, but the organizations suggest a cut -off level between 300 -350 ng/dl. All societies recommend routine laboratory monitoring within the first year and annually after. The guideline committees acknowledge limited data on cardiovascular disease and testosterone. The consensus is to withhold TTh within 3 -6 months of an MI or stroke or in patients with severe heart failure.(2, 4) Prostate cancer is another gray area. Although the consensus is that there is no data to suggest TTh causes prostate cancer.

A drop in testosterone levels over time is more likely to result from a man’s behavioral and health changes than by aging, study suggests. (2012) www.sciencedaily.com

Obesity Aging Hormones Depression Mental Health Sex Testosterone

From the article:

On average, testosterone levels did not decline significantly over five years; rather, they decreased less than 1 percent each year, the authors reported. However, when the investigators analyzed the data by subgroups, they found that certain factors were linked to lower testosterone levels at five years than at the beginning of the study.

“Men who had declines in testosterone were more likely to be those who became obese, had stopped smoking or were depressed at either clinic visit,” Wittert said. “While stopping smoking may be a cause of a slight decrease in testosterone, the benefit of quitting smoking is huge.”

[…]

Unmarried men in the study had greater testosterone reductions than did married men. Wittert attributed this finding to past research showing that married men tend to be healthier and happier than unmarried men. “Also, regular sexual activity tends to increase testosterone,” he explained.

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Testosterone therapy may help improve pain in men with low testosterone. (2013) www.sciencedaily.com

Hormones Testosterone Opioid

From the article:

Previous animal research has demonstrated that castration of rodents is associated with increased pain perception while testosterone replacement reduces pain perception, suggesting an analgesic effect of this sex steroid. Whether these beneficial effects can be replicated in humans, however, remained unclear.

In this study, investigators found that, compared to placebo, testosterone therapy significantly improved pain perception and tolerance [in men] during laboratory pain testing. Testosterone therapy also improved some aspects of quality of life.

“If larger studies confirm these findings, testosterone therapy in this patient population may be beneficial in improving pain perception,” Basaria said.

The study included 84 men ages 18-64 years old with opioid-induced testosterone deficiency. Their average age was 49 years.

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Testosterone therapy increased tissue glucose uptake by 32% in response to insulin in men with type 2 diabetes and low testosterone (2015) www.sciencedaily.com

Hormones Diabetes Insulin Resistance Testosterone Insulin

From the article:

The current study included 94 men with Type 2 diabetes. Prior to being treated, the 44 men in the study with low testosterone levels expressed significantly lower levels of insulin signaling genes and, thus, diminished insulin sensitivity. These men were randomized to receive a testosterone injection or a placebo every week for 24 weeks.

The study found that while there was no change in body weight, testosterone treatment produced a reduction in total body fat of 3 kilograms (more than six pounds) while increasing muscle mass by the same amount.

“Most importantly, we saw a dramatic increase in insulin sensitivity, demonstrated by a 32 percent increase in the uptake of glucose by tissues in response to insulin,” Dandona said. At the same time, there was a similar increase in the expression of the major genes that mediate insulin signaling.

While patients' hemoglobin A1C (HbA1c) levels did not go down, a necessary indicator that testosterone can help control diabetes, Dandona noted that fasting glucose levels had diminished significantly, by 12 milligrams per deciliter. He said that a significant improvement in HbA1c may eventually be seen when longer term studies are carried out.

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Testosterone-deficient men on testosterone therapy lost 6.6 pounds more body fat while dieting but maintained muscle mass. (2016) www.sciencedaily.com

Diet Obesity Hormones Fat Testosterone Muscle

From the article:

For the first 10 weeks, all participants were placed on a strict 600 kcal per day very-low calorie diet. They were also encouraged to abstain from alcohol and perform at least 30 minutes a day of moderate exercise. From the 11th through the 56th week, participants in both groups used a weight-maintenance diet based on the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) Total Wellbeing Diet comprising of normal foods.

Every 10 weeks over the 56-week-long study, 49 men also received injections of 1,000mg of intramuscular testosterone undecanoate, and 51 took placebo.

At the end of 56 weeks, both groups lost roughly 11 kg (24.2 lb). But those in the testosterone group lost almost exclusively fat, while those on placebo lost both lean and fat. The men taking testosterone lost 3 kg (6.6 lb) more body fat than those on placebo and maintained their muscle mass, while those on placebo lost 3.5 kg (7.7 lb) of muscle mass.

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Patients undergoing testosterone-lowering therapy for prostate cancer had an 88% increased risk of Alzheimer's risk. (2015) www.sciencedaily.com

Alzheimer's Cancer Hormones Diabetes Testosterone Prostate Cardiovascular

From the article:

Using two different methods of statistical analysis, the team showed that the ADT [androgen deprivation therapy] group, compared to the control group, had significantly more Alzheimer’s diagnoses in the years following the initiation of androgen-lowering therapy. By the most sophisticated measure, members of the ADT [androgen deprivation therapy] group were about 88 percent more likely to get Alzheimer’s during the follow-up period.

The analyses also suggested a “dose-response effect.” The longer individuals underwent ADT the greater their risk of Alzheimer’s disease, they found. The longer-duration ADT patients also had more than double the Alzheimer’s risk of non-ADT controls.

[…]

How low testosterone would lead to increased Alzheimer’s risk isn’t precisely known, but there is some evidence that testosterone has a general protective effect on brain cells, so that lowering testosterone would leave the brain less able to resist the processes leading to Alzheimer’s dementia. Studies in mice and in humans also have suggested that lower testosterone levels may allow greater production of the Alzheimer’s protein amyloid beta. Moreover, low testosterone may increase Alzheimer’s risk indirectly, by promoting conditions such as diabetes and atherosclerosis that are known to predispose to Alzheimer’s.

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In a study, 40% of obese and 50% of obese diabetic participants had low testosterone levels. (2010) www.sciencedaily.com

Obesity Hormones Diabetes Testosterone

From the article:

Results of a study published online ahead of print in the journal Diabetes Care, conducted by University at Buffalo endocrinologists, showed that 40 percent of obese participants involved in the Hypogonadism in Males (HIM) study had lower-than-normal testosterone readings.

The percentage rose to 50 percent among obese men with diabetes. Results also revealed that as body mass index (BMI) – a relationship of weight-to-height – increased, testosterone levels fell.

“The effect of diabetes on lowering testosterone levels was similar to that of a weight gain of approximately 20 pounds,” says Sandeep Dhindsa, MD, an endocrinology specialist in the UB Department of Medicine and first author on the study.

[…]

This is the largest analysis of the association between obesity and low testosterone, and the first to compare prevalence of low testosterone with obesity and diabetes separately and together. The study shows that obesity and diabetes may exert independent influences on testosterone concentrations.

[…]

UB endocrinologists published a study in Diabetes Care in 2008 showing that more than 50 percent of men between 18 and 35 years old with type 2 diabetes had lower than normal testosterone levels.

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Testosterone replacement therapy may decrease cardiovascular risks in men with low testosterone levels. (2014) www.sciencedaily.com

Hormones Heart Disease Testosterone Cardiovascular

From the article:

Researchers at the Intermountain Medical Center Heart Institute in Murray, Utah, which is the flagship facility for the Intermountain Healthcare system, studied 5,695 men between the ages of 53 and 71. The men, all patients at Intermountain Healthcare hospitals, had initial low testosterone levels.

Researchers found that men who received testosterone supplementation to achieve normal or high testosterone levels had reduced overall rates of major adverse cardiac events at one and three years after their initial low levels of testosterone were measured, compared to other men who had persistently low levels of testosterone. The lower rate of cardiac events included a reduction in the adjusted risk of death and a reduction in heart attacks.

[…]

Smaller studies have been conducted on testosterone replacement therapy and its cardiovascular effects in men, with different results. While it is known that low levels of testosterone pose an increased cardiovascular risk, the risks versus benefits of supplementation have not been clearly identified.

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Exposure to high levels of phthalates may be associated with a decrease in testosterone levels of up to 34%. (2014) www.sciencedaily.com

Hormones Testosterone Environment

From the article:

Animal and cellular studies have found that some phthalates block the effects of testosterone on the body’s organs and tissues. Researchers set out to examine whether these chemicals, which are widely used in flexible PVC plastics and personal care products, had a similar effect in humans.

“We found evidence reduced levels of circulating testosterone were associated with increased phthalate exposure in several key populations, including boys ages 6-12, and men and women ages 40-60”

[…]

Researchers found an inverse relationship between phthalate exposure and testosterone levels at various life stages. In women ages 40-60, for example, increased phthalate concentrations were associated with a 10.8 to 24 percent decline in testosterone levels. Among boys ages 6-12, increased concentrations of metabolites of a phthalate called di-(2-ethylhexyl) phthalate, or DEHP, was linked to a 24 to 34.1 percent drop in testosterone levels.

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Castration-induced sudden drop in testosterone caused Parkinson's symptoms in mice. (2013) www.sciencedaily.com

Parkinson's Hormones Testosterone Nitric Oxide

From the article:

“While scientists use different toxins and a number of complex genetic approaches to model Parkinson’s disease in mice, we have found that the sudden drop in the levels of testosterone following castration is sufficient to cause persistent Parkinson’s like pathology and symptoms in male mice,” said Dr. Kalipada Pahan, lead author of the study and the Floyd A. Davis endowed professor of neurology at Rush. “We found that the supplementation of testosterone in the form of 5-alpha dihydrotestosterone (DHT) pellets reverses Parkinson’s pathology in male mice.”

“In men, testosterone levels are intimately coupled to many disease processes,” said Pahan. Typically, in healthy males, testosterone level is the maximum in the mid-30s, which then drop about one percent each year. However, testosterone levels may dip drastically due to stress or sudden turn of other life events, which may make somebody more vulnerable to Parkinson’s disease.

[…]

“This study has become more fascinating than we thought,” said Pahan. “After castration, levels of inducible nitric oxide synthase (iNOS) and nitric oxide go up in the brain dramatically. Interestingly, castration does not cause Parkinson’s like symptoms in male mice deficient in iNOS gene, indicating that loss of testosterone causes symptoms via increased nitric oxide production.”

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Testosterone may need to be converted to estrogen in the brain to show anxiety- and depression-inhibiting effects, mouse study suggests. (2015) www.sciencedaily.com

Hormones Depression Mental Health Anxiety Testosterone Estrogen

From the article:

He already knew that testosterone had a protective effect on males, just as estrogen and progesterone do on females. He also knew that most testosterone was converted into estrogen in the brain. What he didn’t know was that those anxiety- and depression-inhibiting effects couldn’t be produced unless the testosterone was first converted to estrogen.

“There is an enzyme in the brain that ‘mediates’ the conversion of testosterone into estrogen,” Kabbaj said. “We inhibited that enzyme in a specific brain area implicated in the regulation of mood. And when you do that, you lose the antidepressant effect of testosterone. So the conversion is very important.”

His lab targeted the hippocampus area of the brain, where testosterone acts through what’s known as the MAPK pathway to induce its antidepressant and anti-anxiety effects.

“But we have to be careful about that pathway,” Kabbaj said, “because it’s also implicated in cellular growth and cancer. Therefore, we’re looking for other pathways that don’t have these effects. It’s complicated. Nothing is ever simple, but we’ll get there.”

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Testosterone may cause sex differences in Parkinson's disease risk, rodent study suggests. (2015) www.sciencedaily.com

Parkinson's Hormones Testosterone

From the article:

Parkinson’s is due to the loss of dopamine neurons, cells in the region of the brain that controls movement. Oxidative stress, which is a chemical imbalance triggered by sources such as genetic mutations and exposure to environmental toxins, can harm and kill cells. Researchers at the University of North Texas Health Science Center observed in rats' dopamine neurons that testosterone exacerbated damage induced by oxidative stress, acting through a protein called cyclooxygenase 2 (COX2). Blocking the actions of COX2 blocked testosterone’s effects. These data indicate that testosterone may enhance the damage and death in dopamine neurons induced by oxidative stress, explaining the sex differences in the occurrence of Parkinson’s, the researchers wrote

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The positive effects that daily exercise can have on nerve regeneration may also require androgen signaling, mouse study suggests. (2012) www.sciencedaily.com

Exercise Hormones Testosterone

From the article:

The researchers previously showed that two weeks of moderate daily exercise substantially improves regeneration of cut nerves and leads to functional recovery in mice, though different types of exercise are required to produce the effect in males and females. They now report that these beneficial effects of exercise require androgens such as testosterone in both males and females.

In the study they conducted, they exercised three groups of male and female mice. Nerves of the three groups were cut and surgically repaired. Once group received the drug flutamide, which blocks the androgen receptor. A second group received a placebo treatment. The third group was unexercised. Regenerating nerve fibers in the placebo group grew to more than twice the length of those in unexercised mice in both males and females. In flutamide-treated mice, the effects of exercise were blocked completely in both sexes.

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High-dose testosterone therapy may help some men with advanced prostate cancer. (2015) www.sciencedaily.com

Cancer Hormones Testosterone Prostate

From the article:

Previous studies, he adds, have shown that taking testosterone at the wrong time – particularly by men with symptoms of active cancer progression who have not yet received testosterone-blocking therapy – can make the disease worse.

In men whose prostate cancer spreads, doctors typically prescribe drugs that block testosterone production, but cancer cells eventually become resistant to this means of reducing the hormone, says Denmeade, a professor of oncology at the Johns Hopkins University School of Medicine. At that point, physicians switch to other drugs, such as enzalutamide, which block testosterone’s ability to bind to receptors within prostate cancer cells.

Denmeade says the combination of drugs that block testosterone production and receptors, called androgen deprivation therapy, may make prostate cancer more aggressive over time by enabling prostate cancer cells to subvert attempts to block testosterone receptors. And many men on these drugs experience harsh side effects, including impotence, weight gain, muscle loss and intense fatigue.

[…]

With this context, the new study tested an approach based on the idea that if prostate cancer cells were flooded with testosterone, the cells might be killed by the hormone shock. The cells also might react by making fewer receptors, which may make the prostate tumor cells vulnerable once more to androgen deprivation therapy.

[…]

The men were given three 28-day cycles of an intramuscular injection of testosterone and two weeks of a chemotherapy drug called etoposide. Men who showed decreases in PSA levels after three cycles were continued on testosterone injections alone.

[…]

Of the 14 remaining in the trial, seven experienced a dip in their PSA levels of between 30 and 99 percent, an indication their cancers were stable or lessening in severity. Seven of the men showed no decrease in PSA.

In addition, four of the seven men stayed on testosterone therapy for 12 to 24 months with continued low PSA levels. Of 10 men whose metastatic cancers could be measured with imaging scans, five experienced tumor shrinkage by more than half, including one man whose cancer completely disappeared.

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Testosterone predominance may increase the prevalence of metabolic syndrome during menopause. (2008) www.sciencedaily.com

Hormones Testosterone Estrogen Metabolic Syndrome Cardiovascular

From the article:

“Menopause-related testosterone predominance appears to be implicated as a key hormonal change that is associated with the incidence of metabolic syndrome,” said lead investigator Imke Janssen, PhD, assistant professor, Department of Preventive Medicine at Rush University Medical Center.

It was previously thought that estrogen exerted a direct positive effect on cardiovascular disease risk in women, a benefit that was lost as women transitioned from a premenopausal to a postmenopausal state and experienced a loss of estrogen.

“Our study data shows that the change in estrogen level is, at best, a weak and nonsignificant predictor of metabolic syndrome risk,” said Janssen. “A more likely story is that the progressive testosterone predominance exerts a direct negative effect on cardiovascular risk.”

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In young men who voted for the loser of the 2008 presidential election, testosterone levels dropped after the result was announced. (2009) www.sciencedaily.com

Hormones Testosterone

From the article:

Female study participants showed no significant change in their testosterone levels before and after the returns came in.

The men who participated in the study would normally show a slight night-time drop in testosterone levels anyway. But on this night, they showed a dramatic divergence: The Obama voters' levels didn’t fall as they should, and the McCain and Barr voters lost more than would have been expected.

[…]

The findings mirror what other studies have found in men who participate directly in an interpersonal contest – the winner gets a boost of testosterone, while the loser’s testosterone drops.

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Testosterone therapy over a five-year period may not be associated with an increased risk of aggressive prostate cancer. (2015) www.sciencedaily.com

Cancer Hormones Testosterone Prostate

From the article:

A new population-based study from The University of Texas Medical Branch at Galveston showed for the first time that exposure to testosterone therapy over a five-year period was not associated with an increased risk of aggressive prostate cancer. Further, risk of high-grade prostate cancer did not increase according to the total number of testosterone injections.

[…]

Although several longitudinal studies have shown no increased risk of prostate cancer incidence associated with testosterone use, no population-based studies have examined the association of high-grade prostate cancer with testosterone exposure beyond one year.

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In men with Alzheimer's disease, free testosterone levels were about half those of healthy men. (2004) www.sciencedaily.com

Alzheimer's Aging Hormones Memory Testosterone Lactate

From the article:

Dr. Resnick, Scott Moffat, Ph.D., and their colleagues evaluated the testosterone levels of 574 men, ages 32 to 87, who participated in the Baltimore Longitudinal Study of Aging (BLSA). The investigators examined free and total testosterone levels-measured over an average of 19 years-in relationship to subsequent diagnosis of AD. Based on physical, neurological and neuropsychological exams, 54 of the 574 men were diagnosed with AD.

The research team found that for every 50 percent increase in the free testosterone index in the bloodstream, there was about a 26 percent decrease in the risk of developing AD. Although overall free testosterone levels fell over time, these levels dropped more precipitously in those men who later developed AD. In fact, at the end of the study, men who were diagnosed with AD, on average, had about half the levels of circulating free testosterone as men who didn’t develop the disease. In some cases, the drop-offs in free testosterone levels associated with AD were detected up to a decade before diagnosis.

Previously, Dr. Resnick and her colleagues found that older men with high levels of circulating free testosterone have better visual and verbal memory and perform spatial tasks more adeptly than their peers.

“It is quite possible that circulating free testosterone has a broad range of influences on the aging brain,” Dr. Resnick said.

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The marketing and prescribing of testosterone and growth hormone for aging-associated problems is disease mongering, experts say. (2015) www.sciencedaily.com

Aging Hormones Testosterone

From the article:

The epidemic of testosterone prescribing over the last decade has been primarily pushing testosterone as a tonic for sexual dysfunction and/or reduced energy in middle-aged men, neither of which are genuine testosterone deficiency states.“

[…]

“Clearly, previous attempts to warn doctors and the public of this disease mongering that is potentially medically harmful and costly have not been effective. Now however,” said Perls, “with the FDA’s recent dual commission findings that testosterone treatment is not indicated for age-associated decline in serum testosterone, alternatively called ‘andropause,’ ‘late-onset hypogonadism’ and marketed as ‘low T,’ we have the opportunity to highlight why hormone replacement (also euphemistically called "bioidentical hormone replacement”) for aging with not only testosterone but also growth hormone is disease mongering, that the conjured benefits are unfounded and are far outweighed by the risks, and to provide suggestions about how this deceptive practice can be stopped."

The authors point out that for many men, testosterone does not decline with age among men retaining excellent general health, and if it does, the decline is due to common underlying problems such as obesity and poor fitness. Those who hawk testosterone and growth hormone have developed advertising and in some cases professional-appearing questionnaires that focus on common complaints among older men such as decreased energy, feeling sad, sleep problems, decreased physical performance or increased fat.

Additionally, the authors highlight that many times, a testosterone level won’t even be obtained and the patient is told that, simply based on these common symptoms alone or with minor reductions in serum testosterone, they have “late onset hypogonadism,” or that their erectile dysfunction may be improved with testosterone treatment.

In the case of growth hormone, the FDA requires that doctors perform a test to demonstrate that the body does not produce enough growth hormone. “Those who market and sell HGH for these common symptoms nearly never perform the test because if they did a properly performed test, it would almost never be positive because the diseases that cause growth hormone deficiency in adults, such as pituitary gland tumors, are very rare,” said Perls.

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Risk of heart attack may double shortly after beginning testosterone therapy. (2014) www.sciencedaily.com

Hormones Heart Disease Testosterone

From the article:

So successful has the marketing for this testosterone therapy been that, according to Drugs.com, an independent medicine website, sales of the testosterone gel Androgel in 2013 exceeded sales of Viagra.

Now, a new joint study by UCLA, the National Institutes of Health and Consolidated Research Inc., has shown there is a twofold increase in the risk of a heart attack shortly after beginning testosterone therapy among men under 65 who have a history of heart disease. Further, the study confirmed earlier studies that found a twofold increase in heart attack risk shortly after treatment began in men older than 65.

They examined the health care records of 55,593 men who had been prescribed testosterone therapy – 48,539 under the age of 65 and 7,054 who were 65 or older.

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Testosterone therapy may not be associated with adverse cardiovascular events in men with low testosterone. (2015) www.sciencedaily.com

Hormones Heart Disease Testosterone Cardiovascular

From the article:

But this research also underscores the need for a long-term, prospective, randomized trial to truly understand whether testosterone therapy can be used without putting men at greater risk for cardiovascular events such as heart attacks, worsening of heart failure or sudden cardiac death.

[…]

In the second study, researchers at Aurora Health Care, a large community-based health care system in Wisconsin, analyzed demographic and health data from 7,245 men with low testosterone levels from 2011-2014. After obtaining data from the electronic record systems of 15 hospitals and 150 clinics, the researchers looked at the combined cardiovascular event rate of heart attack, stroke and death in men with low testosterone who received testosterone therapy and in those who did not. They found the event rate at three years was low in both the treated group at 5.5 percent and in the untreated group at 6.7 percent, suggesting a potential cardiovascular benefit of testosterone replacement therapy on initial analysis. However, after adjusting for baseline differences including age, prior heart attack or stroke, cholesterol levels, smoking status and length of follow-up, researchers found no difference in cardiovascular event rates between the two groups.

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Testosterone replacement therapy may help improve the quality of life for deficient elderly men with mild cases of Alzheimer's disease. (2005) www.sciencedaily.com

Alzheimer's Hormones Testosterone

From the article:

“For the patients with AD, the testosterone-treated group had significantly greater improvements in the scores on the caregiver version of the quality-of-life scale,” the researchers report. “No significant treatment group differences were detected in the cognitive scores at end of study, although numerically greater improvement or less decline on measures of visuospatial functions was demonstrated with testosterone treatment compared with placebo. In the healthy control group, a nonsignificant trend toward greater improvement in self-rated quality of life was observed in the testosterone-treated group compared with placebo treatment. No difference between the treatment groups was detected in the remaining outcome measures.”

“In conclusion, the present results should be considered preliminary and do not warrant routine treatment of AD and healthy control men with testosterone. Future studies with larger sample sizes are needed before clinical decisions regarding testosterone therapy can be rationally based. For men with compromised quality of life, as reflected on the type of measure employed in this study, and who suffer from low serum T [testosterone] levels, testosterone therapy may be a reasonable consideration.”

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Restoring testosterone production in men may be as effective as replacing it, without compromising their fertility. (2015) www.sciencedaily.com

Hormones Sex Testosterone

From the article:

While testosterone replacement therapy can boost men’s energy levels, sex drive, and mood, the treatment can fool the body into thinking that it is producing enough testosterone, so that it in turn starts making less of its own. This can result in a significant decrease in sperm count–leading to infertility–because the body needs its own testosterone to produce sperm.

An alternative approach to testosterone replacement is based on restoring the body’s natural production of testosterone with drugs similar to those used to help women ovulate. […] compared such a drug, called Enclomiphene citrate, with testosterone replacement therapy (Androgel) in overweight men with low testosterone, or hypogonadism. In the randomized studies, 44 men started on 12.5 mg of oral enclomiphene citrate daily, with 25 men being up-titrated to 25 mg; 42 men received a topical 1.62 percent AndroGel; and 41 men received a placebo. Over five months, patients had 10 clinic visits with one overnight stay.

The investigators found that Enclomiphene citrate restored blood testosterone levels to normal after 16 weeks while maintaining sperm concentrations, whereas Androgel restored blood testosterone levels but caused marked reductions in sperm concentrations by suppressing the function of the testes.

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Higher testosterone levels may be associated with better cognitive function in older men. (2002) www.sciencedaily.com

Brain Alzheimer's Aging Hormones Memory Testosterone

From the article:

“Our study only looked at natural testosterone levels and so it doesn’t prove that testosterone supplements can prevent cognitive decline. We will need results of large randomized clinical trials in older men before we can confidently say that testosterone supplements are beneficial and safe,” she said.

Taking testosterone, or over-the-counter supplements that boost levels of the hormone, can have side effects including increased risk of prostate cancer, increased cholesterol levels, acne and male pattern baldness, Yaffe said.

[…]

The cognitive tests measured concentration, memory, attention, language, and other cognitive skills. When scores on these tests decline significantly, or are well below average, this serves as a warning of a high risk of Alzheimer’s disease, Yaffe said.

In addition to testosterone, the researchers measured estrogen and sex hormone binding globulin, a protein that binds these two hormones. Although testosterone was linked to better scores on the tests, estrogen had essentially no effect on performance, Yaffe said. Previous studies of women have shown that higher estrogen levels can reduce their risk of cognitive decline.

Other research has shown that men have higher levels of both estrogen and testosterone than women, and that women have a 30 percent greater risk of developing Alzheimer’s Disease, Yaffe said. Some researchers hypothesize that women’s increased Alzheimer’s risk is related to lower hormone levels.

This study doesn’t explain how testosterone acts on the brain, Yaffe said, but other studies of mice have shown that the parts of the brain that handle learning and memory tasks are replete with receptors for testosterone.

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Sleeping only five hours decreased testosterone levels by 10 to 15% in young healthy men. (2011) www.sciencedaily.com

Sleep Hormones Mental Health Testosterone

Sleep deprivation reduces testosterone levels in young men.

Just one week of sleep deprivation reduces young men’s testosterone levels by as much as 15 percent, according to a 2011 study. Missing out on sleep worsened the young men’s mood and overall energy levels, too.

In the study, 10 young, healthy, college-age men got a good night’s sleep for three nights, and then they got just five hours per night for eight nights. Researchers monitored their sleep and collected blood samples from the men every 15 to 30 minutes throughout the last day of each sleep protocol.

They found that getting five hours of sleep a night for just one week drastically reduced the men’s testosterone levels – by as much as 10 to 15 percent. Testosterone levels began to plummet in the afternoons and continued to drop until late at night. The men also experienced marked reductions in their overall energy levels and moods.

Roughly one-third of working adults in the United States get fewer than six hours of sleep every night – a problem linked with a variety of acute and chronic health conditions, including an increased risk of colds, high blood pressure, diabetes, heart attack, heart failure, and stroke. Evidence suggests that poor sleep reduces sex drive.

The findings from this study suggest that getting even a few nights of poor sleep alters testosterone, energy levels, and mood in young, healthy men. Learn about other effects of sleep deprivation in this clip featuring Dr. Matthew Walker.

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In a study of men with low testosterone, 56% of study participants suffered from depression or showed depressive symptoms. (2015) www.sciencedaily.com

Obesity Sleep Hormones Depression Mental Health Sex Testosterone

From the article:

The research, slated to publish online on July 1 in the Journal of Sexual Medicine, involved 200 adult men, aged 20-77, with a mean age of 48 years old, who were referred for borderline total testosterone levels between 200 and 350 ng/dL. Information gathered included demographics, medical histories, medication use, signs and symptoms of hypogonadism, and assessments of depressive symptoms and/or a known diagnosis of depression or use of an antidepressant.

Depression and/or depressive symptoms were present in 56 percent of the subjects. Furthermore, one quarter of the men in the study were taking antidepressants and that the men had high rates of obesity and low rates of physical activity. The most common symptoms were erectile dysfunction, decreased libido, fewer morning erections, low energy, and sleep disturbances.

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Men with low testosterone are at greater risk for developing type 2 diabetes. (2016) www.sciencedaily.com

Hormones Diabetes Testosterone Insulin

From the article:

Doctors have long known that men with low testosterone are at greater risk for developing type 2 diabetes. For the first time, researchers have identified how testosterone helps men regulate blood sugar by triggering key signaling mechanisms in islets, clusters of cells within the pancreas that produce insulin.

[…]

“Our study shows that testosterone is an anti-diabetic hormone in men. If we can modulate its action without side effects, it is a therapeutic avenue for type 2 diabetes.”

Researchers used specially bred male mice with pancreatic beta cells lacking the receptor to testosterone (the androgen receptor). They fed them a Western diet rich in fats and sugar and tested their response to glucose. The mice without androgen receptors all developed lower insulin secretion, leading to glucose intolerance compared with normal mice in the control group.

To better understand how testosterone interacted with insulin production within the pancreas, researchers administered testosterone and glucose directly to human islet cells treated with an androgen receptor inhibitor and islets cells harvested from mice without androgen receptors. In both cases the islet cells showed decreased insulin production compared to islet cells whose receptor to testosterone was not inhibited or missing.

Further experiments in cultured mouse and human islet cells showed the insulin-producing effect of testosterone could be abolished by inhibiting glucagon-like peptide-1 (GLP-1), a hormone the body produces after a meal. The study suggests that testosterone amplifies the islet impact of the hormone, which is currently used as a diabetes treatment.

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Testosterone therapy may boost sexual function and mood in older men with low testosterone levels. (2016) www.sciencedaily.com

Aging Hormones Mental Health Sex Testosterone

From the article:

Yale enrolled the largest number of participants at any one site (84 of 790) for these double-blind, placebo-controlled trials that investigated the efficacy of testosterone gel for multiple outcomes, including sexual function, physical function, and vitality.

The researchers found that men who received testosterone therapy for one year, versus those on placebo, saw significant improvements in sexual function, including sexual activity, sexual desire, and erectile function.

[…]

While participants enrolled in the trial that assessed physical function did not see significant improvements in their walking ability – as measured by an increase of 50 meters or more in their distance walked in 6 minutes – an increase was found when all study participants were evaluated. In addition, men enrolled in the vitality trial saw modest benefits in terms of improved mood and fewer depressive symptoms.

While the results were somewhat mixed, Gill noted an overall benefit that had not been seen in previous studies. “One way of interpreting the results across trials is a global impression of change,” he said. “We found that testosterone improved men’s impression that their sexual desire, walking ability, energy level, and overall health were better.”

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Testosterone administration to deficient older men did not affect atherosclerosis rates, sexual function, or health-related quality of life. (2015) www.sciencedaily.com

Aging Hormones Sex Testosterone Prostate Cardiovascular

From the article:

Shalender Bhasin, M.B.B.S., of Brigham and Women’s Hospital, Harvard Medical School, Boston, and colleagues randomly assigned 308 men 60 years or older with low or low-normal testosterone levels to receive 7.5 g of 1 percent testosterone (n = 156) or placebo (n = 152) gel packets daily for 3 years. The dose was adjusted to achieve testosterone levels between 500 and 900 ng/dL. Characteristics were similar between groups at study entry: patients were an average age of 68 years; 42 percent had hypertension; 15 percent, diabetes; 15 percent, cardiovascular disease; and 27 percent, obesity.

The researchers found that the rates of subclinical atherosclerosis progression, as measured by changes in common carotid artery intima-media thickness or coronary artery calcium, did not differ significantly between men assigned to the testosterone or placebo groups. Changes in intima-media thickness or calcium scores were not associated with change in testosterone levels among individuals assigned to receive testosterone.

Sexual desire, erectile function, overall sexual function scores, partner intimacy, and health-related quality of life did not differ significantly between groups. Hematocrit (a measure of red blood cells) and prostate-specific antigen levels increased more in testosterone group.

The authors write that this trial was not designed to determine the effects of testosterone on CVD events, and that a substantially larger trial would be needed to determine this.

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Testosterone rapidly potentiates the response of neural circuits mediating threat processing and aggressive behavior in men. (2014) www.sciencedaily.com

Brain Hormones Behavior Testosterone

From the article:

The researchers recruited 16 healthy young male volunteers, who completed two test days on which they received either testosterone or placebo. On both testing days, the men first received a drug that suppressed their testosterone. This step ensured that testosterone levels were similar among all study participants. The amount of testosterone administered in this study only returned testosterone levels to the normal range. Subjects then completed a face-matching task while undergoing a functional magnetic resonance imaging scan.

Data analyses revealed that, compared with placebo, testosterone increased reactivity of the amygdala, hypothalamus and periaqueductal grey when viewing angry facial expressions.

“We were able to show for the first time that increasing levels of testosterone within the normal physiological range can have a profound effect on brain circuits that are involved in threat-processing and human aggression,” said Carré, Assistant Professor at Nipissing University.

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Low testosterone levels may be associated with up to 40% higher risk of falling in older men. (2006) www.sciencedaily.com

Aging Hormones Testosterone

From the article:

Eric Orwoll, M.D., Oregon Health & Science University, Portland, and colleagues studied 2,587 men age 65 to 99 (average age 73) who enrolled in the Osteoporotic Fractures in Men (MrOS) Study between 2000 and 2002.

[…]

During the course of the study, which continued until March 2005, 56 percent of the men fell at least once. Those with lower bioavailable testosterone levels were significantly more likely to fall and to fall multiple times than those with higher levels–among the one-fourth of participants with the lowest testosterone levels, the risk for falling was 40 percent higher than among the one-fourth with the highest testosterone levels. The association was stronger in younger men (ages 65 to 69) and not apparent in men older than 80.

The association remained the same when the researchers factored in the scores on physical performance tests.

“Bioavailable testosterone concentration is associated with measures of physical performance, but the association of testosterone level to the risk of falling is apparent regardless of physical performance,” the authors write. “Thus, the mechanisms by which testosterone level affects the propensity to fall may involve other pathways.” For example, low testosterone levels could impair vision, thinking processes or coordination, increasing the risk for falls.

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Testosterone raised the risk of prostate cancer and exacerbated the effects of carcinogenic chemical exposure in rats. (2014) www.sciencedaily.com

Cancer Hormones Testosterone Prostate

From the article:

Two dose-response studies examined the incidence of prostate cancer in rats. The rats were given testosterone through slow-release implant devices. Before the rats were dosed with testosterone, some of the animals were given injections of the carcinogenic chemical N-nitroso-N-methylurea (MNU). These rats were compared to a control group that received MNU but had empty slow-release devices implanted.

Among the rats that received testosterone without the carcinogenic chemical, 10 to 18 percent developed prostate carcinomas. Testosterone treatment alone did not induce specific tumors at other sites, but compared with control rats, it caused a significant increase in the number of rats with malignant tumors at any site. When rats were exposed to testosterone and the carcinogen, the treatment caused prostate cancer in 50 to 71 percent of the rats. Even when the hormone dose was too low to elevate testosterone levels in the bloodstream, half of the rats developed prostate tumors. Animals that were exposed to the carcinogenic chemical but not testosterone did not develop prostate cancer.

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Testosterone may play a role in the lower incidence of knee ligament injuries in males, rodent study suggests. (2016) www.sciencedaily.com

Hormones Testosterone

From the article:

In studies on rats, Johns Hopkins Medicine scientists report new evidence that the predominance of the hormone testosterone in males may explain why women are up to 10 times more likely than men to injure the anterior cruciate ligament (ACL) in their knees.

[…]

Explanations for the sex differences include differences in anatomy, strength, reflex times and hormones.

[…]

Eight of the rats were normal, with testosterone levels averaging 3.54 nanograms per milliliter, and eight had been castrated, giving them nearly undetectable levels of the hormone, at 0.14 nanograms per milliliter. The researchers measured the cross-sectional area of each ACL and then connected the bones – with the ACL stretched between them – to a machine that could pull the bones apart, tugging on the ACL. Then, they tested the strength of the ligaments by measuring how much force it took to tear each ACL.

The researchers found that it took more force – 34.5 newtons, compared to 29.2 newtons – to tear the ACLs from mice with normal levels of testosterone, indicating that the ligaments were stronger. Since researchers have generally accepted that a stronger ACL is less prone to injury, the results support a link between testosterone and ACL injuries.

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Long-term testosterone therapy may help men with deficiency lose weight (-20.3%), maintain their weight loss and reduce death risk. (2019) www.sciencedaily.com

Hormones Testosterone Mortality Weight Loss

From the article:

“Obesity is very common in men with testosterone deficiency (hypogonadism),” said lead study author Karim Haider, M.D., a urologist and andrologist in private practice in Bremerhaven, Germany.

[…]

The 462 (57.4 percent) patients with obesity were given the choice whether to be treated with long-term testosterone therapy (TTh) with testosterone undecanoate injections (TU) 1,000 mg every 12 weeks. Of these, 273 opted to receive testosterone, and the 189 who declined treatment served as controls.

Over 10 years, the testosterone-treated men lost 20.3 percent of their baseline weight (50.5 lb; 22.9 kg); their waist circumference dropped by 12.5 cm (4.9 in). BMI decreased by 7.3 kg/m2, and the waist-to-height ratio decreased by 0.07.

By contrast, the untreated men gained 3.9 percent of their baseline weight (3.2 kg; 7.1 lb), and their waist size increased by 4.6 cm (1.8 in). In this group, BMI increased by 0.9 kg/m2, and waist-to-height ratio increased by 0.03.

During this time, 12 (4.4 percent) men in the testosterone group died, while in the untreated control group, 57 deaths (30.2 percent), 47 myocardial infarctions (24.9 percent) and 44 strokes (23.3 percent) occurred.

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Decreased sexual activity and desire may cause a decline in serum testosterone of less than 10% in older men. (2015) www.sciencedaily.com

Hormones Sex Testosterone

From the article:

Whether decreasing sexual function is a cause or an effect of reduced androgen status in older men, or whether some other age-related factor may be involved, is not clear.

[…]

At both visits, the participants answered questions about their sexual functions, including, “How often are you able to get and keep an erection that is firm enough for satisfactory sexual activity?”; “How many times over the last month have you had sexual activity (including intercourse and masturbation) reaching ejaculation?”; and, “How much desire for sex do you have now, compared with when you were 50?”

[…]

Over two years, baseline serum testosterone, DHT, E2 and E1 did not predict decline in sexual activity, sexual desire and erectile function. By contrast, the decline in testosterone (but not in DHT, E2 or E1) over time, though less than 10%, was strongly related to decreased sexual activity and desire, but not to erectile dysfunction.

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Testosterone protects men from developing allergic asthma by inhibiting a certain type of immune cell, mouse study suggests. (2017) www.sciencedaily.com

Hormones Immune System Testosterone Allergies Asthma

From the article:

“There is a very interesting clinical observation that women are more affected and develop more severe asthma than men, and so we tried to understand why this was happening,” Dr Seillet said.

“Our research shows that high levels of testosterone in males protect them against the development of allergic asthma. We identified that testosterone is a potent inhibitor of innate lymphoid cells, a newly-described immune cell that has been associated with the initiation of asthma.”

The research team found that innate lymphoid cells – or ILC2s – ‘sensed’ testosterone and responded by halting production of the cells.

“Testosterone directly acts on ILC2s by inhibiting their proliferation,” Dr Seillet said. “So in males, you have less ILC2s in the lungs and this directly correlates with the reduced severity of asthma.”

ILC2s are found in the lungs, skin and other organs. These cells produce inflammatory proteins that can cause lung inflammation and damage in response to common triggers for allergic asthma, such as pollen, dust mites, cigarette smoke and pet hair.

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In symptomatic older men with low testosterone, testosterone therapy resulted in sustained improvement in most types of sexual activity. (2016) www.sciencedaily.com

Hormones Sex Testosterone

From the article:

The placebo-controlled, double-blinded trial examined the effect of testosterone therapy on sexual function in a group of 470 men. The men were enrolled in the study through 12 academic medical centers. The participants were at least 65 years old and had low testosterone levels, based on the average results of multiple tests. All of the men had a heterosexual partner.

[…]

The men treated with testosterone therapy displayed consistent improvement in libido and in 10 of the 12 sexual activity measurements, including frequency of intercourse, masturbation and nighttime erections. In comparison, men who received the placebo did not change their questionnaire responses significantly over the course of the year-long study.

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After 8 years of studying 656 men, none of testosterone-treated men died from cardiovascular events vs 19 without therapy. (2017) www.sciencedaily.com

Hormones Heart Disease Testosterone Stroke Cardiovascular

From the article:

The researchers followed a group of men for eight years who had been on TTh [testosterone therapy] and compared them with another group of men who remained untreated for the same time period. They found there were only two deaths in the TTh group and neither was related to CV events. In the non-treated control group, there were 21 deaths, 19 of which were related to CV events. Furthermore, there were 26 non-fatal myocardial infarctions and 30 non-fatal strokes in the control group but none in the T-treated group.

According to the researchers, long-term TTh [testosterone therapy] in men with hypogonadism appears to be an effective approach to achieve sustained improvements in cardiometabolic function and reduces the risk of CV events. “The low CV events observed in the T-group compared to the untreated (control) group strongly suggest that TTh is protective. We believe that the protective effect of T on the CV system provides clinicians with the opportunity to utilize this approach for secondary prevention for hypogonadal men with a history of CV events,” explained corresponding author Abdulmaged M. Traish, PhD, professor of biochemistry and urology at BUSM.

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Aging men with multiple sources of emotional social support often have lower testosterone levels, which may confer social benefits. (2015) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

“Compared to other U.S. men, fathers and married men often have lower testosterone,” Gettler said. “We think this helps them be more nurturing. We are the first to show that this also occurs with other social relationships. Our results show that when older men have emotionally supportive relationships with their siblings, friends, neighbors and coworkers, they also have lower testosterone.”

According to Gettler, “We know that men and women with social support have much better health, overall, while testosterone affects risks for depression, cardiovascular disease, obesity and some cancers. We hope our findings, connecting these two areas, help stimulate new conversations about social support, biology and well-being.

“Most of us have probably seen the TV commercials promoting testosterone as a remedy for symptoms of aging or ‘manopause.’ Our findings suggest that the social side effects of these testosterone supplements in older men should be carefully studied. While testosterone does go down with age, the potential social benefits that can accompany lower testosterone suggest it is not all doom and gloom.”

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After 3 years of testosterone therapy in 755 high-risk men, 22 with high doses suffered cardiovascular events vs. 125 without therapy. (2016) www.sciencedaily.com

Hormones Heart Disease Testosterone Stroke Cardiovascular

From the article:

“The study shows that using testosterone replacement therapy to increase testosterone to normal levels in androgen-deficient men doesn’t increase their risk of a serious heart attack or stroke,” said cardiologist Brent Muhlestein, MD, co-director of cardiovascular research at the Intermountain Medical Center Heart Institute. “That was the case even in the highest-risk men – those with known pre-existing heart disease.”

[…]

The research team studied 755 male patients at Intermountain Healthcare hospitals. The men were between the ages of 58 and 78, and all had severe coronary artery disease. They were split into three different groups, which received varied doses of testosterone administered either by injection or gel.

The conclusions:

– After one year, 64 patients who weren’t taking testosterone supplements suffered major adverse cardiovascular events, while only 12 who were taking medium doses of testosterone and nine who were taking high doses did.

– After three years, 125 non-testosterone-therapy patients suffered major adverse cardiovascular events, while only 38 medium-dose and 22 high-dose patients did. “Although this study indicates that hypo-androgenic men with coronary artery disease might actually be protected by testosterone replacement, this is an observational study that doesn’t provide enough evidence to justify changing treatment recommendations,” Dr. Muhlestein said.

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Testosterone may facilitate social approach by specifically activating the amygdalae if social approach is desired (2015) www.sciencedaily.com

Brain Hormones Behavior Anxiety Testosterone

From the article:

In a double-blind, placebo-controlled study, 54 young healthy women were given 0.5 mg of testosterone (or a placebo) four hours before a brain scan. This dosage is much lower than, for example, that used for a sex change treatment, or as a supplement for sportspeople, but it is sufficient to have a measurable effect on brain activity.

[…]

It seems that testosterone facilitates social approach by specifically activating the amygdalae only if social approach is desired. This is interesting for two reasons. It explains previous research that showed that testosterone makes approaching a social threat easier. Even more important, it shows that the amygdalae are not necessarily linked to dealing with emotions, but rather to motivation. Many studies forget to look at motivation. We are the first to demonstrate that the impact of testosterone on amygdala response depends on the motivational context."

Also in cases of social anxiety?

“We’re now going to repeat this study in people with social anxieties. We have already discovered that these people have lower testosterone levels. We are going consider how we can apply these results with testosterone to improving the treatment for anxiety disorders.”

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Testosterone may directly impact financial decisions that drive prices up and destabilize markets. (2017) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

The study used experimental stock markets with some 140 male participants (called traders) taking part. Cohorts of traders were given testosterone or placebo gel prior to their trading sessions. In total, the experiment consisted of 17 sessions that allowed traders to buy, sell, bid, and offer money for shares of stock, similar to a simplified professional trading platform. Each session had three rounds of 12 trading periods where traders competed to make money against each other.

The results showed the causal effects of testosterone on financial asset mispricing. By administering testosterone to traders before they trade financial assets for real money, testosterone directly increases the size and persistence of stock market bubbles. Testosterone drove these changes in market dynamics by increasing bidding, selling prices, and volume and changed traders' perception of a stock’s current value even though true values were known during trading.

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Per 200 ng/dL of increased testosterone, bone density increased by 6.1% in deficient older men, but arterial plaque formation was also noted. (2017) www.sciencedaily.com

Hormones Testosterone Bone Cardiovascular

From the article:

Researchers found that testosterone treatment improved bone density and estimated bone strength, as determined by quantitative computed tomography (CT). The treatment also increased hemoglobin concentrations, corrected the anemia of men who had no other identifiable cause of anemia and corrected the anemia of men who had an identifiable cause, such as iron deficiency. While these conclusions proved testosterone to be beneficial to the participants, testosterone treatment did not improve memory or any other measure of cognitive function.

[…]

In the cardiovascular trial, researchers assessed coronary artery plaque buildup by CT angiography. That assessment showed more plaque buildup in men treated with testosterone than in men treated with placebo. Nonetheless, in all 788 men in the TTrials, the number of major adverse cardiovascular events was similar in the men treated with testosterone as in the men treated with placebo. However, Snyder added, “treating 788 men for one year is far too few to draw conclusions about the clinical significance of the increase in coronary artery plaque volume and the cardiovascular risk of testosterone treatment.”

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Testosterone may increase risk of heart attack and stroke by promoting vascular calcification. (2016) www.sciencedaily.com

Hormones Heart Disease Testosterone Stroke Cardiovascular

From the article:

Scientists at the University of Edinburgh examined the effects of testosterone on blood vessel tissue from mice. They found that the hormone triggers cells from the blood vessels to produce bone-like deposits – a process called calcification. When the mouse cells were modified, by removing the testosterone receptor, so they could no longer respond to testosterone, they produced far less of the calcium deposits.

The team also looked at blood vessel and valve tissue from people with heart disease who had undergone surgery for their condition. They found that cells from these tissues contained bone-like deposits and also carried the testosterone receptor on their surface. This suggests that testosterone may trigger calcification in people.

Calcification causes blood vessels to harden and thicken, which means the heart has to work harder to pump blood around the body. It is strongly linked to increased risk of heart attack and stroke. Calcification can also affect the heart’s valves, meaning that the valves cannot open and shut properly and may need to be replaced.

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Harmonized normal testosterone range in a healthy non-obese population (19-39 years) is 264-916 ng/dL. (2017) www.sciencedaily.com

Hormones Testosterone

From the article:

A large study of more than 9,000 men has established harmonized reference ranges for total testosterone in men that when applied to assays that have been appropriately calibrated will effectively enable clinicians to make a correct diagnosis of hypogonadism, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

[…]

Researchers used the results from both measurements to generate harmonized values, which were in turn used to derive standardized, age-specific reference ranges overall. The harmonized normal range for testosterone in a non-obese population of European and American Men, 19-39 years, is 264-916 ng/dL.

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Study casts serious doubts on the proposal that testosterone causally impairs cognitive empathy. (2019) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

To obtain more rigorous data on the connection, Nave, Nadler, and their colleagues conducted two randomized controlled studies in which 643 healthy men received an application of testosterone gel or a placebo and completed questionnaires and behavioral tasks that measured cognitive empathy. Participants were then shown a photo of an actor’s eyes and asked to select the emotional state that best described their expression. All participants also had their 2D:4D ratio [ratio of the length of the participant’s second finger to their fourth finger; proxy for sensitivity to testosterone] measured.

While the testosterone gel did increase participants' levels of the hormone, the researchers found no evidence that testosterone administration affected performance on tests of cognitive empathy [capacity to read the emotions of others]. They also found no relationship between participants' performance on the tests and their 2D:4D ratio.

“The results are plain,” says Nave. “However, it’s important to note that the absence of evidence is not evidence of absence. We found that there is no evidence to support this effect of testosterone, but that doesn’t rule out any possible effects. From what we know, though, it seems that if testosterone does have an influence, the effect is complex, not linear. Reality is typically not that simple.”

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A single dose of testosterone increased men's preference for higher status goods. (2018) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

The current study was double-blinded and randomized and used a larger sample size than earlier efforts, 243 men ages 18-55. Each participant received a gel to apply to his upper body; some gels contained testosterone and others a placebo.

In one task, participants were shown two logos of apparel brands selected to match their perceived quality but differ in status, for example, higher-status Calvin Klein versus lower-status Levis. Those who received a dose of testosterone were significantly more likely to prefer the higher-status brands.

The second task presented participants with descriptions of certain goods, such as watches, coffeemakers, and sunglasses, as either power-enhancing, status-enhancing or high-quality and asked about their attitudes toward the products. Here, too, men who received a testosterone boost were more likely to express positive feelings about the items described as status-enhancing, though there was no difference between the groups when the goods were described as power-enhancing.

“We were trying to disentangle power from status,” Nave says. “Typically in the animal kingdom they go together, but you can think of examples in human society where they don’t. For example, a border patrol agent has a lot of power but not status. And a famous climate scientist may have a lot of status but little power.”

Nave notes that testosterone naturally rises in men in certain contexts, such as during and after sporting events, or subsequent to major life events like a graduation or divorce. Marketers could take advantage of these oscillations to tailor their marketing strategies to these individuals.

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Most supplements advertised as testosterone-boosting have little or no known effect. (2019) www.sciencedaily.com

Hormones Testosterone Supplements

From the article:

Using a structured review approach, Samplaski and a team of researchers explored the active ingredients and advertised claims of 50 T boosting supplements. Their findings were published as an original article in The World Journal of Men’s Health.

[…]

Of the 150 supplements, researchers came across 16 general claims to benefit patients, including claims to “boost T or free T,” “build body lean mass or muscle mass,” or “increase sex drive or libido.”

While 90% of the T booster supplements claimed to boost testosterone, researchers found that less than 25% of the supplements had data to support their claims. Many also contained high doses of vitamins and minerals, occasionally more than the tolerable limit.

Table 3 of the publication: Published evidence showing an increase, decrease or no change in testosterone (T) with supplementation

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Testosterone replacement therapy can increase men's risk of stroke and heart attack by 21% during the first two years of use. (2019) www.sciencedaily.com

Hormones Heart Disease Testosterone Stroke Cardiovascular

From the article:

The study analyzed a large database of electronic medical records of patients enrolled in primary care practices in the United Kingdom and formed a cohort of 15,401 men, aged 45 years or older, with low testosterone levels (hypogonadism). Users of TRT [testosterone replacement therapy] had a 21 percent greater risk of cardiovascular events compared with nonusers, corresponding to an additional 128 events. The increased risk appears to be transient, declining after two years of TRT use, which the investigators attribute to a phenomenon called “depletion of susceptibles.”

“Our findings show that the use of TRT was associated with an increased risk of stroke, TIAs [transient ischaemic attack], or cardiac arrest during the first two years of use,” noted Christel Renoux

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Testosterone may protect men from stomach inflammation, mouse study suggests. (2021) www.sciencedaily.com

Autoimmunity Hormones Inflammation Testosterone

From the article:

In researching mice without either glucocorticoids or testosterone, Busada, his research partner John Cidlowski – a senior investigator with the National Institutes of Health – and their colleagues observed that males' stomach inflammation increased as much as the females' did.

What’s more, when he and his team gave testosterone to the female mice, their inflammation vanished.

“We were able to completely rescue them from their stomach inflammation,” Busada said. “We proved that androgens were the hormones giving male mice that double layer of protection from inflammation. In the females, the only anti-inflammatory hormone was glucocorticoids. In males, it could be either glucocorticoids or androgens. This study potentially explains why women have a much higher incidence of autoimmune and chronic inflammatory diseases.”

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Testosterone administration may impair cognitive reflection and decision-making in men. (2017) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

The study, which is one of the largest of its type ever conducted, included 243 males who were randomly selected to receive a dose of testosterone gel or placebo gel before taking a cognitive reflection test. A math task was also given to control for participant engagement, motivation level, and basic math skills.

The questions included on the cognitive reflection test are exemplified by the following: A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?

[…]

The results show that the group that received testosterone scored significantly lower than the group that received the placebo, on average answering 20 percent fewer questions correctly. The testosterone group also “gave incorrect answers more quickly, and correct answers more slowly than the placebo group,” the authors write. The same effect was not seen in the results of the basic math tests administered to both groups. The results “demonstrate a clear and robust causal effect of [testosterone] on human cognition and decision-making,” they conclude.

The researchers believe that the phenomenon they’ve observed can be linked to testosterone’s effect of increasing confidence in humans. Testosterone is thought to generally enhance the male drive for social status, and recent studies have shown that confidence enhances status.

“We think it works through confidence enhancement. If you’re more confident, you’ll feel like you’re right and will not have enough self-doubt to correct mistakes,” Camerer says.

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Exogenous testosterone may increase sensitivity to moral norms in moral dilemma judgements. (2019) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

Instead of the trolley problem itself, the researchers used 24 dilemmas associated with real-life events to simulate a situation that pits utilitarian decisions, which focus on the greater good (saving a large group of people) against deontological decisions, which focus on moral norms (avoiding action that would harm someone).

[…]

Unlike previous studies where heightened testosterone was linked to utilitarian judgments, the researchers were surprised to find that those who received testosterone supplements were less likely to act for the greater good, and instead became more sensitive to moral norms. However, participants with high levels of naturally occurring testosterone showed the opposite, making judgments that were less sensitive to moral norms.

The study’s authors think naturally occurring testosterone may be associated with certain moral judgments because people with particular personality traits tend to have different levels of testosterone. For example, people with high levels of psychopathy tend to have high levels of naturally occurring testosterone and exhibit lower sensitivity to moral norms. But this does not mean that testosterone is the cause of psychopaths' insensitivity to moral norms. If anything, testosterone seems to have the opposite effect, increasing people’s sensitivity to moral norms, as found in the current study.

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Low testosterone levels may be associated with chronic disease, even in men 40 years of age and younger. (2018) www.sciencedaily.com

Hormones Diabetes Cholesterol Depression Testosterone Triglycerides Blood Pressure Arthritis Cardiovascular

From the aricle:

Peterson and team then examined prevalence of nine chronic conditions, including type 2 diabetes, arthritis, cardiovascular disease, stroke, pulmonary disease, high triglycerides, hypercholesterolemia, hypertension and clinical depression.

The researchers studied the prevalence of multimorbidity, or when two or more of the chronic conditions were present, among three age groups (young, middle-aged and older men) with and without testosterone deficiency. They found that low total testosterone [<300 ng/dL] was associated with multimorbidity in all age groups – but it was more prevalent among young and older men with testosterone deficiency.

“We also found a large dose-response relationship between the age-specific low total testosterone and moderate total testosterone levels and multimorbidity, even after adjusting for obesity and muscle strength capacity,” Peterson says. “Which means that men should be concerned about declining total testosterone, even if it has not reached a level to warrant a clinical diagnosis (<300 ng/dL [10.4 nmol/L]).”

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Men who believed they had won a sporting competition received an average testosterone increase of 4.92%. (2018) www.sciencedaily.com

Hormones Behavior Testosterone

From the article:

The study used a simple proxy for social and sexual competition by pitting athletic young men against each other to see who was the most powerful rower.

[…]

The men who believed they had won received an average testosterone increase of 4.92%, while those convinced they had lost dropped by an average of 7.24%. Overall, men who thought they were winners had testosterone levels 14.46% higher their deflated opponents.

[…]

The men who thought they had lost showed no difference in their perceived value as a mate or confidence approaching women. However, the men who felt like winners had a ‘self-perceived mate value’ that was 6.53% higher, on average, than their rivals, and were 11.29% more likely to approach attractive women in an effort to instigate sexual relations.

“The endocrine system that controls hormones is responsive to situational changes. Previous research has shown that testosterone is lower when men are in a committed relationship, or have children, to promote long-term mating strategies,” said Longman.

“Our results show that both testosterone and its corresponding psychological effects can fluctuate quickly and opportunistically, shifting towards short-term mating in response to a perceived change in status that may increase mating value.”

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Seven days of exposure to acetominophen reduced testosterone by 45% in mouse model of in utero testicular development www.sciencedaily.com

Hormones Pregnancy Sex Testosterone Development

From the article:

The University of Edinburgh study tested the effect of paracetamol on testosterone production in mice that carried grafts of human testicular tissue. These grafts have been shown to mimic how the developing testes grow and function during pregnancy.

Scientists gave the mice a typical daily dose of paracetamol – over a period of either 24 hours or seven days. They measured the amount of testosterone produced by the human tissue an hour after the final dose of paracetamol.

They found there was no effect on testosterone production following 24 hours of paracetamol treatment. After seven days of exposure, however, the amount of testosterone was reduced by 45 per cent.

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Increasing testosterone during aerobic exercise may be a unique quality of only high-intensity exercise: 31% increase from 40 mins maximum intensity www.mdpi.com

Testosterone Aerobic

Intense aerobic exercise modulates testosterone levels. Testosterone is the primary male sex hormone. It plays critical roles in reproductive health and contributes to bone and muscle mass accretion. A recent review summarizes the effects of aerobic exercise on testosterone levels.

Aerobic exercise can be defined as physical activity that increases aerobic metabolism – the body’s energy-producing processes that require oxygen. Examples of aerobic exercise include walking, running, swimming, dancing, and other activities that increase heart rate and respiration. Exercise intensity – the physiological demand it creates on the body – is a critical modulator of exercise-induced changes in testosterone concentrations. Intensity is often captured as a percentage of a person’s maximal oxygen consumption (VO2max).

The reviewers highlighted the findings of studies that focused on exercise intensity and testosterone response. In one study, investigators assessed changes in testosterone after low, moderate, or high intensity aerobic exercise on an exercise bike and found that only high-intensity exercise increased testosterone. Another group of investigators found that exercise intensity was the critical determinant in whether testosterone levels increased, especially if the number of repetitions remained constant. The group conducted another study in which runners using a treadmill experienced incremental increases in exercise intensity, ranging from 60 to 100 percent of the runner’s VO2max. They found that the runners' testosterone levels began to increase when the runners reached 90 percent of their VO2max and remained high at 100 percent VO2max. About one hour post exercise, the runners' testosterone returned to baseline levels. The reviewers also described research demonstrating that duration and hydration status influence testosterone levels, as well.

The findings presented in this review suggest that intense aerobic exercise promotes increases in testosterone levels, ultimately influencing reproductive and musculoskeletal health. Learn about other beneficial health effects of aerobic exercise in our overview article

Link to full publication.

12-week exercise program of 40-60 minutes of jogging three days per week significantly improved testosterone and systolic b.p. in overweight men www.sciencedaily.com

Exercise Hormones Sex Testosterone Blood Pressure Aerobic Weight Loss

40-60 minutes 3x per week:

Systolic blood pressure: 134 ± 4 vs. 119 ± 3 (after)
Diastolic blood pressure: 85 ± 2 vs. 75 ± 1 (after)

From the article:

At baseline, the overweight/obese men had significantly lower total, free and bioavailable testosterone level than normal weight men. All of the study volunteers completed a 12-week aerobic exercise plan that entailed 40-60 minutes of walking or jogging on one to three days per week.

[…]

I think decrease in body mass is one of the factors for increasing serum testosterone levels,“ said Hiroshi Kumagai, lead researcher on the study. "However, the degree of weight loss is small, and we found that the increase in vigorous physical activity was independently associated with the increase in serum testosterone levels. So, it seems the increase in physical activity, especially vigorous physical activity, is the main factor for increasing serum testosterone levels.”

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EPA and DHA supplementation increases serum testosterone levels in males with overweight and obesity. pubmed.ncbi.nlm.nih.gov

Omega-3 Testosterone

Long-chain omega-3 fatty acids, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), increase serum testosterone levels in mice, although the mechanisms that drive these benefits are unclear. While omega-3 fatty acids improve cellular function, omega-6 fatty acids serve as precursors to pro-inflammatory cytokines, such as arachidonic acid, which damage cells. Findings from a recent report detail the effects of long-chain omega-3 fatty acids and omega-6 fatty acids on serum testosterone levels in adults with overweight and obesity.

Omega-3 fatty acids are essential nutrients found in the oils of fatty fish, such as salmon. In humans, they increase cellular membrane flexibility, which improves cellular function. Omega-6 fatty acids are the primary fats in most vegetable oils, such as corn oil. In excess, omega-6 fatty acids can be harmful to health. Leydig cells, located in the testicles, produce testosterone when stimulated with luteinizing hormone. Evidence from studies in mice suggest that long-chain omega-3 fatty acids incorporate into the plasma membranes of Leydig cells increasing their responsiveness to luteinizing hormone and increasing testosterone synthesis..

The authors recruited 22 males with overweight and obesity who did not have type 2 diabetes to participate in the study. Participants consumed either fish oil (providing 860 milligrams of DHA and 120 milligrams of EPA per day) or a placebo (1 gram of corn oil per day) for 12 weeks. They provided blood samples for the analysis of sex hormones and metabolic markers and completed questionnaires about health, diet, dietary supplement use, and other lifestyle factors.

Fish oil supplementation significantly increased serum testosterone concentrations, even after taking into account age and body mass index. This increase in testosterone occurred with an increased concentration of omega-3 fatty acids in the membranes of red blood cells, an indicator of the membrane composition of Leydig cells. The researchers reported an even stronger association between increased testosterone and decreased omega-6 fatty acid concentration in red blood cell membranes. They also noted improvements in insulin sensitivity among the supplemented group compared to the placebo group.

These findings demonstrate that long-chain omega-3 fatty acid supplementation increased serum testosterone levels in males with overweight and obesity. The authors noted that their report is a secondary analysis of a larger clinical trial and that future research with a larger sample of participants is prudent.

Link to full report.

Fish oil supplementation improves testicular function in young males without infertility. jamanetwork.com

Omega-3 Testosterone Supplements

Evidence suggests that sperm quality in males over the past 50-70 years has declined, likely due to a combination of dietary and lifestyle factors and exposure to endocrine-disrupting chemicals. For example, diets rich in processed meats, full fat dairy, and sugar-sweetened beverages are associated with poor sperm quality, whereas diets rich in vitamins, minerals, and unsaturated fats improve sperm quality and fertility. Results of a recent observational study demonstrate the effects of fish oil supplementation on sperm quality and testicular function in healthy young males.

Infertility affects 15 percent of couples, with male and female reproductive dysfunction contributing equally to infertility rates. Previous epidemiological research has revealed an association between fish consumption and better sperm quality in males seeking infertility treatment. Fish and fish oil supplements are an excellent source of omega-3 fatty acids, a type of polyunsaturated fat with numerous anti-inflammatory and health-promoting properties. Two previous randomized, controlled trials have reported increased antioxidant capacity and decreased DNA fragmentation in the sperm of males experiencing infertility who were supplemented with omega-3 fatty acids. However, the effects of supplementation in men without infertility is unknown.

The investigators recruited more than 1,600 male participants (average age, 19 years) who presented for a physical examination for military service in the Netherlands. Participants volunteered to provide a blood sample for the measurement of sex hormones and a semen sample. Finally, they answered a questionnaire about health, lifestyle, diet, and dietary supplement use over the previous three months.

Only 5.8 percent of the participants had consumed fish oil supplements in the previous three months and only 3.1 percent consumed fish oil supplements for more than 60 days over the previous three months. Participants who supplemented with fish oil less than 60 days had increased sperm volume and testicle size compared to those who did not supplement. Participants who supplemented for more than 60 days had even greater sperm volume and testicle size. Participants who supplemented with fish oil also had a 20 percent lower concentration of follicle-stimulating hormone and a 16 percent lower concentration of luteinizing hormone, an indication of better testicular cell function and greater capacity for sperm production.

The authors concluded that fish oil supplementation improves testicular function in males without infertility, even after taking into account the intake of other dietary supplements. Because this study did not take dose into account, randomized clinical trials are needed to further examine this relationship.

Link to full report.

Testosterone levels drop in response to glucose consumption regardless of weight status or glucose tolerance. pubmed.ncbi.nlm.nih.gov

Testosterone Sugar

Hypogonadism, a disorder in which dysfunction of the ovaries or testes results in the diminished production of sex hormones, is a growing concern, demonstrated by a marked increase in prescriptions for testosterone replacement. Previous research has reported lower serum testosterone in males with type 2 diabetes and metabolic disease. To expand on this observational research, investigators aimed to determine the effects of a glucose challenge on testosterone levels.

Testosterone levels change in response to food intake, which activates the secretion of messenger molecules from the hypothalamus that affect the reproductive organs. While some studies have reported a decrease in serum testosterone in response to glucose intake, others have found an increase in serum testosterone in response to a dose of insulin. The mechanisms underlying the relationship between glucose intake and testosterone levels have yet to be illuminated.

The authors conducted their investigational study with a group of 74 healthy males (19 to 74 years old) of varying weight status who had not been diagnosed with type 2 diabetes. The researchers administered an oral glucose tolerance test in which participants consumed 75 grams of glucose, which is roughly the amount of sugar in two cans of sugar-sweetened soda, and had their blood drawn before consuming the glucose (baseline) and at 30, 60, 90, and 120 minutes afterward. The researchers also collected blood for the measurement of testosterone and other hormones, including luteinizing hormone, which stimulates testosterone production.

At baseline, 57 percent of the participants had normal glucose tolerance, 30 percent had impaired glucose tolerance, and 13 percent met the criteria for a diagnosis of type 2 diabetes. Glucose intake resulted in lower serum testosterone at all time points following glucose consumption, with an average maximum decrease of 25 percent from baseline levels. The authors reported no changes in plasma concentrations of luteinizing hormone or cortisol and a significant decrease in plasma levels of the hormone leptin. Finally, they reported no differences in testosterone response between men of varying glucose tolerance or weight status.

The investigators concluded that a challenge of 75 grams of glucose significantly decreased serum testosterone levels, although the mechanisms that drove the decrease are still unclear, given that no changes in luteinizing hormone were found.

Link to full report.

Sugar-sweetened beverage consumption is associated with lower testosterone levels in younger adult males. www.ncbi.nlm.nih.gov

Testosterone Sugar

Sugar-sweetened beverages are the largest source of added sugar in the American diet. The over consumption of sugar-sweetened beverages is linked to insulin resistance and to multiple diseases including obesity, type 2 diabetes, cardiovascular disease, and gout. One group of investigators aimed to determine the relationship between sugar-sweetened beverage consumption and serum testosterone.

Testosterone is essential for masculine development during puberty and reproductive capacity in adult males. Epidemiological evidence has revealed higher serum testosterone levels in males without diabetes compared to males with diabetes and in active males compared to sedentary males. Previous clinical research has reported a relationship between sugar-sweetened beverage consumption and decreased sperm motility and fertility; however, its relationship with testosterone has not yet been demonstrated.

The authors reviewed data from the 2011-2012 National Health and Nutrition Examination Survey, a large-scale survey research project that tracks the health and nutrition of adults and children in the United States over time. Research staff for this project administer an interview to participants to collect dietary and demographic information and medical, dental, and laboratory tests to collect physiologic measures.

The investigators of this report specifically chose a sample of younger males (between ages 20 and 39 years) because this is the period when fertility is highest. They categorized participants (545 males total) into four levels of sugar-sweetened beverage consumption with participants in the lowest level consuming 137 calories of sugar-sweetened beverages or less per day and the highest consuming 442 calories or more per day.

Ninety percent of participants had a normal testosterone level, defined as greater than 231 nanograms per deciliter. Participants in the highest level of sugar-sweetened beverage consumption were more than twice as likely to have low serum testosterone. After taking into account other factors, including age, race/ethnicity, poverty/income, tobacco and alcohol consumption, and physical activity the authors also found that participants with overweight and obesity were nearly four times more likely to have low serum testosterone compared to lean males, independent of sugar-sweetened beverage consumption.

This report demonstrates that sugar-sweetened beverage consumption and higher body mass index were both associated with lower testosterone levels in males. These associations were independent of each other and not due to other demographic and lifestyle factors.

Link to full report.

Sugar exposure reduces production of sex hormone-binding globulin, a predictor of metabolic health. www.sciencedaily.com

Testosterone Estrogen Sugar

Obesity and metabolic disease are associated with reduced fertility and alterations in several markers of reproductive health, including plasma concentrations of sex hormone-binding globulin. Low levels of sex hormone-binding globulin are common in those with obesity and are predictive of cardiovascular disease and type 2 diabetes risk, although it is unclear how glucose and insulin regulation affect sex hormone-binding globulin levels. A group of investigators recently performed a series of experiments with the aim of identifying mechanisms of sugar metabolism and sex hormone-binding globulin production.

Sex hormone-binding globulin, which is produced by liver, transports sex hormones in the blood and regulates their uptake by sensitive tissues. Hepatocyte nuclear factor-4α, also produced by the liver, stimulates sex hormone-binding globulin production and increases serum testosterone by decreasing its half-life. De novo lipogenesis, the process by which the liver converts excess sugar into fatty acids, suppresses hepatocyte nuclear factor-4α activation and sex hormone-binding globulin production.

In the first experiment, the researchers used transgenic mice whose genomes had been altered to express the human sex hormone-binding globulin gene. They fed these mice a diet high in either sucrose, glucose, or fructose (three types of simple sugars) for one week and measured blood levels of sex hormone-binding globulin. In a second experiment, the researchers exposed human liver cells to varying amounts of insulin and to high concentrations of either glucose or fructose and measured gene expression. Finally, they exposed the same type of liver cells to varying concentrations of glucose and fructose and to the fatty acid palmitate and measured gene expression.

After five days a high fructose diet reduced sex hormone-binding globulin levels in the mice by fructose 80 percent. Sex hormone-binding globulin levels decreased by 40 percent on a high glucose diet and 50 percent on a high sucrose diet. Insulin exposure did not affect sex hormone-binding globulin production in mice. In liver cells, glucose and fructose exposure over five days reduced sex hormone-binding globulin accumulation by 50 percent. This change corresponded to a three- to fourfold reduction in the expression of hepatocyte nuclear factor-4α. Additionally, glucose or fructose exposure over five days resulted in a two- to threefold increase in palmitate production (due to de novo lipogenesis), which corresponded to reductions in sex hormone-binding globulin. Finally, exposure to varying amounts of palmitate over five days reduced hepatocyte nuclear factor-4α expression and sex hormone-binding globulin production.

The authors of this comprehensive study concluded that excess sugar intake resulted in increased de novo lipogenesis, which led to a suppression of hepatic HNF-4α activity, which in turn attenuated sex hormone-binding globulin expression. This work provides a detailed explanation of why sex hormone-binding globulin is a sensitive biomarker of metabolic syndrome and why simple sugars, especially fructose, decrease fertility.

Link to full report.

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