Creatine is found almost entirely in skeletal muscle, where the compound helps to fuel the energy bursts needed for explosive contractions such as those in weight training. Athletes take creatine supplements to give their muscles as much creatine as their cells can handle, expecting to gain extra energy, train longer and harder - and bulk up. And many studies have indicated creatine works. Athletes who take it get stronger and bigger, although some of the increased size may be the result of water retention. Training with steroids produces greater strength gains, but the male hormone supplements are illegal for use as a training aid, not to mention potentially dangerous.
Risks range from heart disease to baldness.
Creatine, on the other hand, is widely available and legal. The Food and Drug Administration lists it as a food supplement and allows it to be sold with no more restrictions than those on vitamins. Teen athletes can buy it at their local health food store - possibly their local supermarket. Many teens do, but no one knows how many. Yesalis, who studies athletes' quests for better bodies through chemistry, would like government agencies such as the Centers for Disease Control and Prevention to add questions on substances such as creatine to their health habits surveys.