While much of the public attention has been focused on androstenedione, other performance- enhancing supplements are also gaining popularity, says Jeffrey Stout, PhD, assistant professor of exercise science and director of the human performance laboratory at Creighton University in Omaha, Neb. Chief among these other supplements is creatine. "The body synthesizes creatine, and it is stored in muscles. But, we have found that supplementation can increase creatine levels," he says.
Creatine can be supplemented by increasing dietary sources, with fish being the best dietary source. "But, it is probably more efficient to use supplements," Stout says. "I have no doubt that creatine is safe and that supplementation can improve performance." But, he says, the impact varies from person to person. For example, "an elite athlete will probably not get a big boost, but an intermediate level athlete will demonstrate an improvement. A vegetarian is likely to show the greatest impact because they don't take in much dietary creatine," he says.
Jose Antonio, PhD, associate professor of health at the University of Delaware, says the biggest problem with supplement use is "that most of the advice about taking them comes from the high school graduate behind the counter at the health food store." He urges athletes and nonathletes who are considering taking supplements to seek advice from "physicians or scientists or someone trained in nutrition. Don't rely on the person behind the cash register."