The fountain of youth apparently does not yet come in a pill or a patch.
Widely used DHEA supplements and testosterone patches failed to deliver their touted anti-aging benefits in one of the first rigorous studies to test such claims in older men and women. The substances did not improve the participants' strength, their physical performance, or certain other measures of health.
"I don't think there's any case for administering these" to elderly people, said Dr. K. Sreekumaran Nair of the Mayo Clinic, lead author of the study, published in today's New England Journal of Medicine.
DHEA, a steroid that is a precursor to the sex hormones testosterone and estrogen, is made by the body, but levels decline rapidly after age 25. DHEA supplements are marketed as rejuvenating agents, and U.S. sales hit $50 million last year.
Testosterone is available by prescription only. But the Food and Drug Administration classifies DHEA as a supplement, so it can be sold without meeting the same safety and effectiveness standards as a drug.
Some athletes use DHEA and testosterone to try to boost performance, often in violation of athletic association rules.
The NFL and other professional sports have banned DHEA. Cycling officials have moved to strip the Tour de France title from winner Floyd Landis, after a French laboratory found elevated testosterone levels in his urine.
Apart from this type of use, scientists have wondered if the substances might help older people. Studies with rodents offered tantalizing results that showed DHEA seemed to decrease fat and fight diabetes and heart disease.
The new study was done by researchers at the Mayo Clinic in Minnesota and the University of Padua in Italy. Over two years, the researchers studied 57 women and 87 men, all of them at least 60 years old. The women were given standard daily doses of DHEA or identical fake pills. The men were given real or fake DHEA and testosterone patches or placebos.
Blood samples were taken every three months. Participants also were examined for any changes in body fat, hormone levels, bone density, and performance on treadmill, weightlifting and leg flexibility tests. They also filled out questionnaires about how they felt.
Although DHEA and testosterone levels increased in the men and women who took the real treatments, there was no effect on physical performance, quality of life or the body's ability to lower levels of blood sugar.