The Power of Creatine: It’s Real but Subtle

For years, scientists and doctors insisted there were no safe shortcuts when it came to building muscle. Illegal anabolic steroids may provide a boost but they also increase the risk of acne, liver failure, heart disease and other conditions, along with turning some users into aggressive jerks. The pills and powders peddled in vitamin shops may be legal, but there has never been any scientific proof that they work.

Then came creatine monohydrate, which for the last decade has been the most popular dietary supplement among jocks in the United States. Nutrition Business Journal, a trade publication, estimated creatine sales at $260 million in 2000, and observers say the magic muscle powder’s popularity continues to grow.

Baseball sluggers Barry Bonds of the San Francisco Giants and the Chicago Cubs’ Sammy Sosa have acknowledged using creatine supplements. Chances are, some of the guys at your local gym are swallowing the stuff too. But creatine also made headlines recently when an editorial in a medical journal raised new questions about its safety. What the heck is creatine, anyway, and can it boost your biceps without endangering the rest of your body?

Creatine is high-grade muscle fuel. Your body naturally produces this amino acid to spark bursts of energy, like when you raise a barbell or run sprints. A typical diet provides a gram or two each day; meat and fish are good sources. Creatine is stored in muscle, but reserves are exhausted quickly during intense exercise. That’s why lifting heavy weights and running at top speed causes us to tire quickly.

Scientists, however, figured out that consuming high doses of creatine can elevate stored levels of this critical fuel. In theory, a muscle that’s well-stocked with creatine should be able to work extra long. For a weightlifter, that means more repetitions, which should lead to more brawn.

Since the early 1990s, dozens of studies have been published examining whether creatine lives up to its promise. In most cases, it has come up a winner. “It appears that creatine can be effective for improving performance and increasing strength and power in athletes,” said physiologist Melvin H. Williams, a professor emeritus of exercise science at Old Dominion University and co-author of “Creatine: The Power Supplement” (Human Kinetics, 1999).

If you decide to try creatine, don’t expect a Popeye-like eruption of vigor next time you hit the gym. The effects of creatine on human performance are real, but subtle. According to University of Connecticut kinesiologist William Kraemer, most studies have shown that adding creatine supplements to your diet may produce a 5% to 10% increase in power. That would mean, for example, that a guy who can normally bench-press 150 pounds eight times before pooping out might be able to squeeze out an extra repetition or two.

It’s easy to see why a competitive athlete would want to gain a little more power--perhaps the difference between a home run that barely clears the fence or a ball caught at the edge of the outfield. But is it worth it to you?

First, there’s the cost. Some creatine devotees begin a regimen by taking 20 grams a day for a week, then downing a “maintenance dose” of 5 grams a day thereafter. I shopped around on the Internet and found prices as low as 20 cents per 5-gram dose. Because pure creatine is relatively cheap to produce, however, manufacturers frequently blend it with other supplements to jack up the price. I found one product that would cost about $150 a year if used daily. (The Food and Drug Administration doesn’t closely monitor the purity and potency of creatine or any other dietary supplement, so you can never be sure you’re purchasing a high-quality product.)

Creatine supplements are worthless for about 20% to 25% of people, since their muscle cells are naturally brimming with the stuff, says Kraemer. For the rest of us, taking more than the recommended dose is a waste of money since only small amounts are needed to reach capacity. “Once you’re loaded up, your body has no place to put it,” says Williams, so the unused creatine is passed in the urine. If you’re an endurance athlete, such as a long-distance runner, creatine supplements won’t give you a stronger kick; aerobic power relies on other energy sources.

Then there are those lingering safety issues, though evidence that creatine is dangerous is largely circumstantial.

In 1997, three college wrestlers died during weight-loss workouts over a six-week period. When reports surfaced that one of the young men had been using creatine, speculation mounted that the supplement may have led to fatal levels of dehydration, since the amino acid is known to draw water from the blood and into muscle cells. The Centers for Disease Control and Prevention investigated the incidents and found no evidence that creatine played a role in the deaths.

More recently, an editorial published in the August issue of the journal Neurosurgery questioned whether creatine, as well as the herbal stimulant ephedra, might be responsible for an increase in the number of deaths from heatstroke among football players in the United States since 1995.

The authors, University of West Virginia neurosurgeon Julian Bailes and two other physicians, wrote that the number of football players who die of heatstroke each year has risen about fourfold in this country since Congress passed a 1994 law allowing companies to sell dietary supplements without first proving that they are safe. Since then, sales of supplements have soared.

Bailes and his colleagues offer no proof that any of the players who dropped dead at football summer camps were using creatine. In an interview, however, he points out that anecdotal reports of side effects among creatine users include muscle cramping, gastrointestinal problems and dehydration--reason enough, he says, to avoid the supplements if you’re exercising in hot weather.

“I don’t think people ought to be taking supplements of any kind in extreme environments,” Bailes says.

That seems like reasonable advice. Yet, last year, Kraemer and several colleagues published a study in Medicine and Science in Sports and Exercise in which they had 20 men pedal stationary bicycles for half an hour in a heat chamber cranked up to 98 degrees Fahrenheit and 80% humidity. Half of the men were dosed with creatine. But when the researchers measured heart rate, blood pressure and how much sweat the men produced, they found no difference between the two groups.

Scientists have reviewed the medical literature for evidence that creatine poses a serious health threat. And, says Kraemer, “nobody’s found a boogeyman.” Still, most studies involving creatine have been conducted over a few days or weeks, and researchers say studies that last longer are needed before anyone can say whether using the supplements for years has any ill effects on health.

Regardless of your motivation for trying creatine--looking good in a muscle T-shirt, perhaps--keep in mind that it won’t re-form your physique unless you lift weights on a regular basis. Other than Popeye’s spinach, there’s no substitute for hard work.

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Massachusetts freelance writer Timothy Gower can be reached by e-mail at tgower@attbi.com. The Healthy Man runs the second Monday of the month.