Androstenedione, the over-the-counter supplement once used by Mark McGwire, does raise testosterone above normal levels and could be hazardous, Harvard researchers say in a study financed by Major League Baseball.
Scientists say additional study is needed to determine whether andro enhances athletic performance.
A study last year found that the over-the-counter drug had no effect on testosterone levels or strength.
The new study lasted just one week and did not measure whether andro can do what promoters claim–make muscles bigger. But the researchers said andro could have that effect because it increases levels of the male hormone.
“I would caution against [taking andro] because we don’t know what the long-term effects are,” said Dr. Benjamin Leder, who led the study published in Wednesday’s Journal of the AMA.
