Body-Building Aid Questioned

Touted as Mark McGwire's not-so-secret weapon in his home run hitting arsenal, Androstenedione has been touted to increase levels of the male hormone testosterone.

Now comes the first evidence that the risks may far outweigh any benefits reports CBS News Correspondent John Roberts.

Researchers at the University of Iowa studied 20 men who took the manufacturer's recommended dose of 300mg/day, and found Androstenedione did not raise testosterone levels nor did it increase strength.

It did, however, lower levels of good cholesterol, raising the risk for heart disease.

Harvard researcher Joel Finkelstein, who is conducting a larger study of Androstenedione for Major League Baseball, says there appear to be other side effects. "Androstenedione increases estrogen levels in men, and it is possible that that could lead to such things as breast enlargement."

Critics of the supplement say that it is enough evidence to take Androstenedione off the market. Its use is already banned by the Olympics, the NCAA and NFL. Major League Baseball, which allows players to take Androstenedione, is expected to revisit the issue when its own study is completed later this summer.