Creatine pills may aid memory and cognition.

The popular muscle-building supplement creatine can boost performance on mental tests. Students preparing for exams might benefit from taking creatine in much the way that some competitive athletes do, an Australian neurochemist suggests.

Creatine, an amino acid produced by the body and also obtained from meat in a person's diet, helps cells store ready-to-use energy. When taken during weight training, pills containing synthetic creatine accelerate gains in muscle strength. Creatine's popularity among athletes and body builders fuels a market of more than $200 million per year for the pills in the United States.

Increased blood flow to the brain accelerates metabolism when someone confronts a challenging mental task, but an energy debt in taxed brain cells can last for several seconds. To see whether extra creatine could help meet the brains demands during quick thinking, Caroline Rae of the University of Sydney and her colleagues gave a daily pill to each of 45 university students who were vegetarians. The researchers suspected that creatine might help vegetarians more than omnivores, who acquire the compound from their diets.

For 6 weeks, half the volunteers received pills containing 5 grams of creatine. The rest received sham pills. Researchers tested all volunteers with a battery of memory and timed analytical tasks at the beginning and end of the trial. After 6 weeks' wait, the researchers conducted an identical trial, except that volunteers got whichever treatment--creatine or placebo--they hadn't received the first time. Neither the volunteers nor the administrators of the tests were told who was taking which pill at which time.

In both trials, volunteers receiving creatine scored better than placebo-treated volunteers on measures of memory and analytical skills, Rae and her colleagues will report in the Oct. 22 Proceedings of the Royal Society of London B. In one test, for example, volunteers taking creatine could recall an average of 8.5 consecutive numerical digits, but those receiving the placebo pill remembered only 7 digits.

The Australian government funded the research. Past studies had suggested that creatine supplements can protect against the effects of certain neurological diseases.

The new findings are "truly remarkable," says Markus Wyss of Roche Vitamins in Basel, Switzerland. Roche does not currently sell creatine supplements, he says.

"This is the first study to show a beneficial effect of creatine supplementation on mental performance. If confirmed, the findings may ... justify much broader use of creatine," Wyss says. "Nevertheless, [larger] studies need to be performed before the potential impact on human health can be fully judged."

If people use creatine to enhance memory and mental performance, they might take it for years at a stretch, Wyss says. The long-term safety of creatine supplementation hasn't been well tested, but the compound can exacerbate health problems in people with diabetes or kidney dysfunction.

Ronald L. Terjung of the University of Missouri in Columbia questions whether nonvegetarians would enjoy the creatine benefits observed in the study. He also says that, despite the study's design, volunteers may have known when they were getting the real supplements. Creatine can cause bad breath, flatulence, and weight gain from excess water retention--cues that might have encouraged volunteers to unconsciously push harder on the tests, he suggests.