Testosterone is the primary male sex hormone and an androgen, though it is present and plays a role in both males and females. In males, testosterone is crucial for the development of male reproductive tissues like the testicles and prostate. It also promotes secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. Furthermore, testosterone is associated with increased aggression, sex drive, and a range of behavioral characteristics.
In both sexes, testosterone contributes to overall health and well-being, influencing mood, cognition, social and sexual behavior, metabolism, energy levels, and the cardiovascular system. It also aids in the prevention of osteoporosis. The hormone is produced in the testes in men, the ovaries in women, and the adrenal glands in both sexes. Testosterone levels in men usually peak between the ages of 20 and 30, gradually declining by approximately 1% per year after age 30 or 40. Insufficient testosterone levels in men may lead to frailty, increased body fat, anxiety, depression, sexual performance issues, and bone loss. Testosterone therapy, including injections, gels, and patches, can be used to treat low testosterone levels.
