What is testosterone?

Hormone produced in the testicles in men and the ovaries in women. Although found in much higher levels in men than women, testosterone is essential in both men and women for maintaining muscle mass, libido, and immune system function. Testosterone also protects against cardiovascular disease, osteoporosis, and type 2 diabetes. In men higher testosterone levels have also been closely associated with a lower risk of prostate cancer. Testosterone is also a mood enhancer and imparts a sense of wellbeing. Testosterone levels begin to decline in both men and women around age 30.