Levels of a hormone produced in the testes predict age-related diseases in men.
“INSL3, or insulin-like peptide 3, is produced in the Leydig cells of the testes and, to a lesser degree, the theca cells of the ovaries. Although it plays important roles in male reproductive maturation and health, evidence suggests it affects other aspects of human health, including bone and muscle physiology, brain function, and others.”