Testosterone

Testosterone is the primary male sex hormone and an anabolic steroid. In men, testosterone plays a key role in the development of male reproductive tissues such as the testis and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. In addition, testosterone is essential for health and well-being, and for the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss. Testosterone is also used as a medication to treat male hypogonadism and certain types of breast cancer. Since testosterone levels gradually decrease as men age, synthetic testosterone is sometimes prescribed to older men to counteract this deficiency.