February 11, 2000

A study led by researchers from the MGH has found that 300 milligram (mg) doses of androstenedione — a dietary supplement used by some athletes — can raise blood testosterone levels in healthy young men. The report, in the Feb. 9 issue of the Journal of the American Medical Association also showed an increase in estrogen levels with both 100 and 300 mg doses. It did not examine whether taking androstenedione increases strength or muscle mass or whether androstenedione has long-term side effects.

"A lot of people have been taking androstenedione under the assumption that it will raise their testosterone levels," says Joel Finkelstein, MD, of the MGH Endocrine Unit, the report's senior author. "This is the first study to show that sufficient doses do raise serum testosterone. But we now need to go on and study whether that increase actually translates into changes in athletic performance or into negative health effects."

The research team — led by Benjamin Leder, MD, also of the MGH Endocrine Unit — found that young men receiving daily 300 mg doses of androstenedione over a seven-day period had increased testosterone levels averaging 34 percent. Testosterone levels returned to normal within a day of androstenedione administration. Levels of two types of estrogen increased significantly at both 100 and 300 mg levels.

While this study examined only the direct effect of androstenedione on hormone levels, the authors noted that long-term increases in testosterone or estrogen can have serious side effects in susceptible patient populations. "We simply don't know what the long-term effects are of taking a supplement that changes one's hormone levels," says Leder. "However, if a patient of mine asked whether or not to take this supplement, I would have to caution against it."

David Schoenfeld, PhD, of the MGH Biostatistics Department was a coauthor of the report.