Testosterone is a hormone that has a unique effect on a man's total body. It is produced in the testes and in the adrenal glands. It is to males what estrogen is to females. Testosterone helps to build protein and is essential for normal sexual behavior and producing erections. It also affects many metabolic activities such as production of blood cells in the bone marrow, bone formation, lipid metabolism, carbohydrate metabolism, liver function and prostate gland growth.
