TESTOSTERONE, FREE

This test measures the amount of unattached, or “free,” testosterone in your blood.

Testosterone is a male sex hormone (androgen) that helps male features develop. Most testosterone is made in the testes (in men) and the ovaries (in women). A small amount is made in the adrenal glands.

Testosterone causes the changes that occur in boys during puberty. It helps hair and muscles grow. It also helps the penis and testes grow. Testosterone also causes a boy’s voice to deepen. Men continue to make testosterone. It boosts sex drive and helps make sperm.