Testosterone is usually thought of as a male hormone, but women have it, too. Testosterone production is substantially lower in women than it is in men. After puberty, a woman begins to produce a constant, adult level of testosterone. The production is split 50-50 between the ovaries and the adrenal glands. In men, the testes produce 95 percent of their testosterone.
Women manufacture approximately one-seventh of the amount of testosterone each day that men do.
If you give testosterone replacement to testosterone-deficient women, they often say they feel better, but they're not specific as to how. One of the tough things about research in this area is what has been measured and what hasn't. Testosterone levels, muscle mass and bone strength have been measured. When testosterone levels in the blood increase, bone density generally improves. Although a few researchers have attempted to measure changes in sex drive and overall quality of life, these important effects are much more difficult to assess.