Caffeine: Athletes' Secret Weapon, and Legal, Too

If Alex Rodriguez had only known. Caffeine is a performance-enhancer that helps athletes go longer and faster, and isn’t a banned substance. Caffeine works by turning fat into extra fuel, releasing calcium stored in muscles, and numbing the brain’s sense of exhaustion. The triple whammy improves performance by an average 5%—up to 25% in the lab—the New York Times reports.

It doesn’t take much to achieve such results: Two cans of Coke can wire a 176-pound man. Overindulgence—measured at nine times that amount—can, however, diminish results. Used right, the boost helps even regular caffeine consumers, but many athletes and coaches still avoid it. “They would see it as against the spirit of the law, even though it’s not,” says an athlete. (More performance-enhancing drugs stories.)