A controversy swirled around Major League Baseball this week as Mark McGwire of the St. Louis Cardinals acknowledged taking a muscle-building substance called androstenedione. The 6'5'', 250-pound McGwire, who is closing in on Roger Maris' home-run record, maintains that androstenedione is a "natural" substance. Major League Baseball allows players to take androstenedione, which is available over the counter, but the NFL, the International Olympic Committee, and the NCAA ban it. What is androstenedione? Is Mark McGwire taking a performance-enhancing steroid?
Officially no, unofficially yes--it all depends on the fine print of steroid classification. The Food and Drug Administration, which monitors such substances for the U.S. government, classifies androstenedione as a "dietary supplement." In other words, the FDA views androstenedione more as a food than as a drug. However, McGwire is right to say that androstenedione occurs "naturally" in the body. Many steroids, including estrogen, are found naturally in the body.
But steroids experts believe that androstenedione has slipped through the FDA's cracks. Its chemical structure resembles that of compounds defined as steroids (i.e., "drugs") by the FDA. Also, androstenedione stimulates the production of testosterone (like "official" steroids) to increase lean muscle mass and hasten the healing process after injury. Medical experts believe that the use of androstenedione, like the use of steroids, can also cause side-effects such as sterility, though notably few studies exist on the subject.
The unofficial evidence persuaded the NFL, the IOC, and the NCAA to classify androstenedione as a steroid and to ban it. However, Major League Baseball plays by the FDA's rules: It prohibits "all illegal drugs and controlled substances, including steroids or prescription drugs, for which the individual in possession of the drug does not have a prescription." FDA "dietary substances" are allowed under this definition, so Mark McGwire is in the clear--until the majors ban androstenedione.
This item was written by Kate Galbraith. Explainer thanks Don H. Catlin, M.D., the Director of the UCLA Olympic Analytical Laboratory.