March 10, 2004 -- People who take the over-the-counter supplement DHEA to increase testosterone may get less, and more, than they bargain for. New research suggests that instead of raising testosterone levels, the supplement raises levels of a hormone that promotes prostate problems.
Classified as a nutritional supplement in 1994, dehydroepiandrosterone, or DHEA, is used by athletes and body builders to build muscle mass because it is broken down into various steroid hormones, including the male sex hormone testosterone. But scientific evidence supporting it's effect on enhancing athletic performance is scant. Homerun slugger Mark McGwire sparked interest in hormone supplements like DHEA a few years later when he acknowledged using them during his record-setting season.
"All kinds of athletes, including high-school kids, are using DHEA, often at much higher doses than are recommended," University of Southern California researcher Rebecca Z. Sokol, MD, MPH, tells WebMD. "Yet most of the research has looked at the effect of this drug on aging men. It has hardly been studied at all in young men who are taking it to improve athletic performance."
Sokol and colleagues recruited 12 men between the ages of 18 and 42 for their study, which is published in the March issue of the journal Fertility and Sterility. The men took either 50 mg of DHEA, 200 mg of DHEA, or a placebo every day for six months, and their blood levels of various hormones were tested at intervals throughout the trial.
The researchers expected to see increases in testosterone, but blood levels of this hormone stayed the same. But circulating levels of a hormone known as ADG, which is a byproduct of testosterone, did increase.
"Our findings suggest that DHEA is quickly turned into testosterone, and then just as quickly turned into [another hormone] DHT, and finally ADG," Sokol says.
Long-Term Risks Unknown
Studies have linked ADG to prostate enlargement, a condition that is almost universal among older men but rarely seen in men under the age of 40. Prostate enlargement was not seen among the study participants taking DHEA, but Sokol says the study follow-up period may have been too brief to detect a change.
"The concern is that young men who take this supplement long term will end up with enlarged prostates at younger ages than they ordinarily would," she says. "I am not of the school that thinks no one should ever take an anabolic steroid. That is absolutely not my perspective. But the fact is, we don't know much about the long-term risks of this drug."
Supplement expert and American College of Sports Medicine spokesman Doug Kalman, MS,RD, agrees, but says the USC study was far too small to offer definitive answers. He adds that elite athletes have all but abandoned the supplement because there is also little evidence that it helps build muscles.
"I am pretty sure that you would find that less than 1% of baseball players or football players at the professional or college level take this stuff," he says. "Most of the studies that have found positive uses for DHEA have been in older men, older women, or people who are HIV positive. No study has ever found a benefit among athletes."