DHEA: Evidence for anti-aging claims is lacking

K. Sreekumaran Nair, M.D.

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DHEA has long been touted as an anti-aging therapy, used to ward off chronic illness and maintain energy and vigor. But clinical trials have found little evidence to back up these DHEA claims.

Here, K. Sreekumaran Nair, M.D., an endocrinologist at Mayo Clinic, Rochester, Minn., who has studied DHEA supplements, answers questions about DHEA.

What is DHEA?

Your body naturally produces the hormone DHEA, or dehydroepiandrosterone, in your adrenal glands, which sit atop your kidneys. Your body uses DHEA to produce a number of other hormones, including the male and female hormones testosterone and estrogen.

A synthetic version of DHEA is also available in pill form and sold as an herbal supplement in the U.S. In other countries, the manufacture of DHEA is regulated and the compound is sold as a prescription drug.

What does DHEA have to do with aging?

The levels of DHEA in your body peak in your 20s and then slowly begin falling as you age. It isn't clear why your body slows DHEA production, and doctors don't know what effect those falling DHEA levels have on your body.

Some people believe lower DHEA levels cause or contribute to aging, since the falling DHEA levels coincide with the decline in body functioning that's commonly seen in aging. Some people argue that low levels of DHEA may be the cause of some common age-related changes, such as decreasing muscle mass, decreasing bone density and declining ability of the immune system to fight disease. If these aging-related changes are due to declining DHEA levels, then taking DHEA supplements to maintain levels seen in younger people should slow the aging process. But there's no evidence to support this.

While some short-term studies have shown tantalizing evidence that suggest beneficial effects from DHEA, other studies haven't confirmed this. For instance:

• Higher DHEA levels have been associated with longevity in both people and primates. But no experimental data are available to show that maintaining peak DHEA levels in older adults can prolong their lives.
• When given to rats, DHEA prevents many age-related changes. But unlike humans, rats have very low DHEA levels to begin with, so it isn't clear how this information could apply to humans.

A Mayo Clinic study published in the New England Journal of Medicine in 2006 examined DHEA supplements in older adults and found no benefits. The study lasted two years and compared a group of older adults who didn't take DHEA supplements with a group that did. DHEA levels went up in the group that took DHEA supplements. But there were no differences between the two groups in body composition, muscle strength, physical endurance, bone density, insulin sensitivity or quality of life. The study concluded that DHEA was not helpful as an anti-aging supplement.

What are the side effects of DHEA?

Very little is known about the potential side effects of DHEA. Some studies of DHEA have linked the supplement to:

• Reduced high-density lipoprotein (HDL, or "good") cholesterol levels
• Increased facial hair in women
• Acne

Long-term adverse effects of DHEA remain to be determined. Because DHEA can, in theory, raise testosterone and estrogen levels in your body, most doctors caution against these supplements if you have an increased risk of prostate cancer or breast cancer. Some forms of these and other cancers can be fueled by hormones, and it isn't clear whether DHEA could contribute to this.

DHEA supplements may also interfere with prescription medications, other nutritional supplements and laboratory tests. So check with your doctor before taking DHEA. Together you can weigh the risks and benefits. 

What do you tell people who want to try DHEA?

Don't take DHEA to prevent, delay or reverse any of the aging-related changes in your body. If you are taking DHEA for these reasons, you're urged to stop taking it. If you plan to take DHEA, don't take it. DHEA has no proven beneficial effect, and its possible adverse effects are uncertain.