Creatine

Claims, Benefits: Improves athletic performance.

Bottom Line: Some small studies show that this amino acid boosts muscle strength short-term in young, highly trained subjects. It serves no purpose for casual exercisers, and offers little to most athletes. You're better off with a solid training program.

Full article, Wellness Letter, April 2002:

Creatine: Behind the Hype

Of all ergogenic aids—supplements that are supposed to improve athletic performance—creatine has probably been getting the most attention. Mark McGwire, Sammy Sosa, and the L.A. Lakers take it, along with many other professional baseball, basketball, football, and hockey players, if you believe the reports. Creatine supplementation has been likened to carbo-hydrate-loading, except that the latter boosts performance in endurance (aerobic) events such as marathons, while creatine is used for high-intensity (anaerobic) activities lasting less than one minute, such as sprinting, jumping, and weight lifting.

Creatine is an amino acid, but unlike most amino acids it is not incorporated into protein. The best sources are meat, poultry, and fish. In the body it's found mostly in the muscles (in the form of creatine phosphate), where it plays a unique role in energy production—it helps restore a compound called adeno-sine triphosphate (ATP), which supplies quick energy. On average, people get 1 to 2 grams of creatine a day from food. The body also makes it in the liver, pancreas, and kidneys.

Why few, if any, should try it

• Some small, short studies (most sponsored by companies that make the supplements) have found that creatine may slightly boost short-term muscle strength and the body's ability to perform very short, high-intensity activities. Most have involved only young, highly trained athletes. But some studies have found no benefits.

• If creatine does have an effect, it would help only in activities that require such short, explosive bursts of energy. That would limit its usefulness to only a small group of athletes. It won't help with aerobic performance, and may, in fact, impair it. That's a big drawback, since most sports and types of exercise call for both aerobic and anaerobic energy.

• Reported side effects include diarrhea, dizziness, and cramping, which can impair performance, though these have not occurred in most studies. Weight gain (from water, not muscle) is also a potential problem.

• The long-term health effects of high doses of creatine are unknown, especially for people who have liver or kidney problems or diabetes. Taking creatine supplements may depress the body's own synthesis of the substance, which may not return to normal once you stop taking the supplements. At high doses, kidney damage is a possibility, though probably not if you take them for only a few days.

• Your muscles can store only so much creatine. Most people have adequate levels, so taking the supplements would have little or no effect.

• If creatine did improve performance, the difference would be very small. Such a small edge might be important for some competitive athletes, but it is meaningless for casual exercisers or players.

• The creatine regimen isn't simple (you take it four times a day). It comes in pills, powders, capsules, and liquids, but the powdered form is most common. It's expensive (cheaper brands simply contain less of the stuff). And the powder tastes lousy, even when mixed with a sweet drink.

• And as with any supplement, there's no guarantee that the creatine is pure or correctly labeled, since there's virtually no government monitoring. Chemical contaminants can form
during the processing of creatine supplements, and some of these may be toxic.

Bottom line: There's no reason for recreational athletes to try creatine supplements, and even competitive athletes should think twice before taking them.

UC Berkeley Wellness Letter, April 2002