Contrary to popular claims, none of the supplements described in the fact sheet, including melatonin, DHEA (dehydroepiandrosterone), human growth hormone (hGH), testosterone, and estrogen, has been shown to prevent or reverse aging. Research ultimately may reveal important health benefits from some of the supplements, in addition to those already confirmed. But, in the meantime, scientists are concerned about the dangerous side effects associated with some of the supplements, and about the possibility of undiscovered health risks.
Consumers can buy DHEA and melatonin over the counter, resulting in widespread use unsupervised by physicians. Part of the scientists' concern stems from the fact that research on melatonin and DHEA, and of unconventional "anti-aging" uses of other, more well-established hormone supplements, is relatively new. With the exception of testosterone and estrogen, researchers have not had time to complete the carefully controlled, long-term studies that are needed to show how these hormone supplements affect people over time.
Testosterone, estrogen, and hGH are available by prescription only, and in cases of genuine deficiency, have been shown to confer important health benefits when taken under a doctor's supervision. However, unsupervised use of any hormone supplement can lead to health problems.
DHEA supplements may affect the body in some of the same ways as testosterone and estrogen. Research has demonstrated that melatonin supplements can, under certain circumstances, affect the body's sleep/wake cycle to enhance sleep.
Hormones are powerful chemicals produced by glands. Whether made internally by glands or taken externally as supplements, hormones enter the bloodstream and travel throughout the body. Tiny amounts of hormones may have far-reaching effects. Several NIA-funded studies of hormone supplements are under way.
In addition to the new fact sheet, other NIA publications on aging-related topics are available through the same toll-free number, 1-800-222-2225, and on the NIA home page (http://nih.gov/nia).
The NIA leads the Federal effort supporting medical and social research on aging and the special needs of older people.