Half of the testosterone produced in women is made by the ovaries; the other half comes from the adrenal glands. Testosterone is important for maintaining muscle mass, strength, and endurance. It is important for proper vitality and energy levels. Adequate testosterone levels have been shown to improve memory and mood. Testosterone is important in burning fat, especially in the abdomen. It is also important for preserving libido and enhancing orgasms. It protects from osteoporosis and cardiovascular disease. It lowers the risk of heart disease by lowering cholesterol and triglyceride levels and normalizing blood clotting.

Artherosclerosis increases as testosterone levels decrease. Testosterone reduces blood glucose levels by increasing insulin sensitivity, resulting in less abdominal fat. Testosterone has also been thought to increase creativity and confidence. Testosterone helps preserve the integrity of the skin by increasing skin tone. Synthetic testosterone, such as methyltestosterone, does not have all of the same benefits and may even cause damage to the heart by increasing LDL cholesterol and decreasing HDL cholesterol.

Unlike estrogen and progesterone, a woman's ovaries continue to produce testosterone after menopause. Most of this testosterone is converted into estrogen and this is where the majority of a menopausal woman's endogenous estrogen comes from. Testosterone peaks around age 25 and its production, like most hormones, diminishes with age. Supplemental testosterone is important for most women, and if a woman has had her ovaries removed, it is especially important. Testosterone levels are highest around ovulation, which is responsible for increasing libido at the proper time for fertilization. The first signs of too much testosterone are acne and facial hair.