Definition: Testosterone is a sex hormone secreted by the adrenal glands in both males and females, though men produce up to 10 times more testosterone than women. Testosterone is an anabolic steroid and it is the main sex hormone in men as well as playing a role in immune function and libido.
Testosterone
By Paige Waehner, About.com
Updated August 23, 2007
About.com Health's Disease and Condition content is reviewed by our Medical Review Board
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