Testosterone

Testosterone is known as a “male” sex hormone, but females have testosterone in smaller amounts. Testosterone is made by the testicles (or testes), the part of the male reproductive system that makes sperm; the ovaries, the part of the female reproductive system that makes eggs; the adrenal glands, organs on top of each kidney that make several hormones. During male puberty, testosterone causes body hair, muscle growth, and a deepening voice. In adult life, it controls sex drive, maintains muscle mass, and helps make sperm. In females, testosterone is important for the growth of bones and muscles, and healthy organs. There are different forms of testosterone in your blood that may be measured to help diagnose certain health problems. Most of your testosterone is attached to proteins. The proteins prevent your tissues from using the testosterone right away, which helps control the amount of “active” testosterone in your body. Testosterone not attached to proteins is called free testosterone. Free testosterone acts on your tissues.