Total Testosterone and Free Testosterone: A Critical Hormone for Men and Women

Mention the hormone testosterone and most people immediately think of men and male characteristics like a deep voice and greater muscle mass. Like other hormones, however, testosterone is vitally important for women as well as for men. As in men, levels of testosterone in women peak in their twenties and decline thereafter, especially after menopause.

In an article published in 1999 in the journal Clinical Endocrinology and Metabolism, Dr. Susan Davis, a renowned researcher in the area of female sexual function, offered a detailed report on testosterone replacement therapy in women.17 Dr. Davis wrote that in women who are postmenopausal or have had an oophorectomy (surgical removal of the ovaries), judicious therapy with testosterone has produced direct, sustained improvement in sex drive, arousal, and frequency of sexual fantasies.

Besides helping women enjoy a more fulfilling sex life, testosterone may help them ward off heart disease and breast cancer. An intriguing report in the Journal of Women’s Health examined the hypothesis that testosterone deficiency is a key factor in heart disease in aging women or women who have had a hysterectomy, since these women have a threefold greater risk of cardiovascular disease compared to women who have not had this surgery.18 The study authors postulated that the “data we have demonstrating cardioprotective effects of testosterone, together with what we know about the loss of testosterone production both in instances of oophorectomy with hysterectomy and in women whose remaining ovarian function has been compromised by hysterectomy, point to testosterone deficiency as a significant factor [in] the reported increased incidence of cardiovascular risk factors [in women].”

Testosterone production declines precipitously in aging men. Most anti-aging physicians consider plummeting testosterone levels to be a biochemical hallmark of the condition known as andropause. Testosterone levels peak in a man at approximately the age of 30. By the age of 40, 5% of men are thought have low testosterone, a figure that rises sharply to at least 40-50% by the age of 70.19 With this drop in testosterone comes deleterious effects such as declines in libido, sexual function, muscle mass, and strength, and a greater incidence of fatigue and depression.

Multiple studies have shown that testosterone supplementation improves sexual function, increasing both libido and erectile function.20-22 Other studies have demonstrated that testosterone helps alleviate many other symptoms of andropause—relieving depression, restoring loss of energy, and lowering levels of potentially dangerous low-density lipoprotein (LDL), often a marker of heart disease.23,24 Testosterone supplementation can also help reverse the debilitating effects of muscle loss (sarcopenia) and osteoporosis that are often seen in older men with low testosterone levels.25,26

Yearly testosterone level checks are very important in monitoring a man for andropause. However, it is also important to ensure that your doctor checks your free testosterone level—that is, testosterone that is not protein-bound—to determine optimal testosterone levels. A number of middle-aged male patients who have come to me with andropausal symptoms had total testosterone levels within normal levels (and were thus told by their doctors that their symptoms were “all in your head”), but had clinically low free testosterone levels. If this is the case, then supplemental testosterone can help men restore their vitality and zest for life when andropause hits.

The Life Extension Hormone Panel tests testosterone and free testosterone for both men and women.

Balancing Estrogen and Progesterone—in Men and Women

Men produce estrogen and progesterone, though they produce far less estrogen than do premenopausal women. In the Life Extension Hormone Panel, men are measured for estradiol and progesterone, whereas women are measured for total estrogens and progesterone.

Just as testosterone is intimately associated with masculinity, estrogen and progesterone are related to femininity. As with testosterone, however, the association is not as simple as it seems. While it is true that estrogen is what makes a woman a woman, and that hormonally healthy men do not produce much estrogen, categorizing estrogen and progesterone as purely female hormones would be just as erroneous as labeling testosterone an exclusively male hormone.

When a woman reaches puberty, her body begins to produce more estrogen. Estrogen is actually three hormones—estradiol, estrone, and estriol—and is produced in a woman’s ovaries, body fat, and adrenal glands. Throughout a woman’s lifetime, estrogen promotes bone strength, protects heart and brain function, and maintains sex drive. During perimenopause and menopause, decreasing estrogen levels can cause hot flashes, night sweats, mood swings, headaches, vaginal dryness, and other symptoms.

Decreasing levels of progesterone, another hormone whose production increases at the start of puberty, can cause irritability, headaches, and anxiety. Only by monitoring and maintaining a balance between these two vitally important hormones can a woman avoid many of the most distressing symptoms associated with menopause. Moreover, regular hormone testing can also reveal whether estrogen levels are too high, which can lead to life-threatening diseases such as breast cancer, or too low, which can lead to debilitating conditions such as osteoporosis.

Until very recently, estrogen and progesterone were thought to play little, if any, role in men’s health. Fortunately, we now know otherwise. Estrogen, which is also produced by men, is important for bone health. In fact, a just-released study of 793 men reported in the American Journal of Medicine showed that men with lower levels of estrogen had a more than threefold greater risk of hip fractures compared to men with higher estrogen levels.27

While maintaining adequate estrogen levels may help protect men against bone fractures, having too much estrogen relative to plummeting levels of testosterone may predispose them to prostate cancer. A recent article published in the World Journal of Urology summarized the possible link between estrogen and prostate cancer: “Estrogenic stimulation . . . in a milieu of decreasing androgens [testosterone] contributes significantly to the genesis of benign prostate hyperplasia, prostate dysplasia, and prostate cancer.” 28

If you ask most conventional medical doctors whether men need progesterone, the answer may well be “no.” In fact, emerging research shows that progesterone—which, like estrogen, is produced in small amounts in men—is vitally important for optimal health in men. Like testosterone levels, progesterone levels decline in aging men. Researchers believe that one of progesterone’s roles in men is to inhibit the toxic effects of excess estrogen. Progesterone is also thought to protect men from prostate cancer by stimulating genes that prevent the cellular overgrowth seen in both prostatic hypertrophy and prostate cancer.29

PSA Testing For Men

Prostate-specific antigen (PSA) is a protein manufactured by the prostate gland in men. Elevated levels may suggest an enlarged prostate, prostate inflammation, or prostate cancer. PSA levels may also be used to monitor the efficacy of therapeutic regimens for prostate conditions.

Elevated levels of PSA may not necessarily signal prostate cancer, and prostate cancer may not always be accompanied by expression of PSA. Levels can be elevated in the presence of a urinary tract infection or an inflamed prostate. A PSA level over 2.5 ng/mL, or a PSA doubling time (the time required for PSA value to double) of less than 12 years, may be a cause for concern.

Conclusion

Achieving and maintaining an optimal balance among the body’s vital chemical messengers is critical to ensuring lifelong health and well-being. Through regular blood testing, aging adults can keep abreast of their hormone status and use hormone supplementation as needed to optimize their quality of life and protect against many of the most dreaded diseases of aging.

Edward R. Rosick, MD, is a board-certified physician in preventive and holistic medicine, and assistant professor of medicine at Michigan State University.