Where it comes from: Creatine is a nitrogen-containing organic acid that is naturally produced from amino acids in the kidney and liver. Small amounts are also found in meat. Creatine was first identified in the 1800s and, in the 1970s, Soviet researchers found that taking creatine supplements may improve athletic performance. Within the next 20 years, creatine had become a popular natural way to enhance performance and build lean body mass.

What it’ll do for you: “Although hundreds of studies have been conducted to see whether creatine can improve athletic performance, there is still not a definite answer,” says Dr. Mark Kantor, an associate professor of nutrition and food science at the University of Maryland. When creatine is added to a workout regimen, the data suggest that supplements can improve athletic performance in high intensity events of short duration, such as 50-yard or 100-yard sprints. The benefits seem most likely to occur when exercising for 30 seconds or less. Some studies also indicate that creatine can improve muscle strength and help weight lifters improve performance during resistance training. For example, it may help weight lifters complete more repetitions per set, and recover more rapidly between sets.

“Taking creatine can make muscles look bigger,” Kantor points out. “Some of this is due to an increase in the muscle itself, but some increase occurs simply because more water is being taken up by the muscles.”

Logically, creatine supplements have been largely investigated as a possible treatment for muscular, neuromuscular, neurological and neurodegenerative diseases (such as arthritis, congestive heart failure, Parkinson’s disease, disuse atrophy, gyrate atrophy, McArdle’s disease, Huntington’s disease, Lou Gehrig’s disease and others). A Harvard study found that creatine is twice as effective as certain prescription drugs in extending the lives of mice with the Lou Gehrig’s disease. Similarly, vegetarians who took 5 grams of creatine per day for six weeks showed a significant improvement on various tests of intelligence. The group who took the supplements was able to repeat longer sequences of numbers from memory and had higher overall IQ scores than the control group. A study of young adults found that only two grams a day failed to prove any improvements. Turns out, five or more grams of creatine can make you stronger and smarter.

It’s also been found that patients with chronic heart failure have low levels of creatine in their hearts. More studies are needed but some so far have reported that creatine supplements may improve heart muscle strength, body weight and endurance in patients with heart failure. Other studies found that the supplement may also help increase bone density, depression and high cholesterol.

Suggested intake: Most popular among adolescent athletes—particularly football players, wrestlers hockey players, gymnasts and lacrosse players—many experts worry the supplement is often taken in excess of recommended doses. In the professional world, reports found that 25 percent of pro baseball players and up to 50 percent of footballers use creatine supplements.

How much is a safe amount? “I suggest no more than 20 grams of creatine per day,” says Kantor. “Creatine ‘loading’ is often done by taking four 5-gram doses of creatine daily.” Food sources do not contain much creatine, and the amounts added to energy drinks are usually very small, so Kantor says dietary supplements—within that 20-gram limit—are the best choices. Creatine monohydrate is the preferred form.

Research shows that 5 to 20 grams per day appears to be very safe and poses few risks of adverse side effects, while also effectively improving physiological response to resistance exercise, increasing the maximal force production of muscles. Note: Experts recommend good hydration (drink water!) during creatine use.

Associated risks/scrutiny: The muscular results may not be noticeable for everyone. According to Dr. Ronald Cox, a professor at the University of Miami, 20 to 30 percent of creatine users are actually non-responders and will see no benefit.

“I caution men from believing that creatine is a magic bullet that will definitely build muscles or make you a better athlete,” warns Kantor. “Creatine supplements do not take the place of hard workouts with lots of sweating. The best way to build muscles or become a faster athlete is by training, not by taking supplements.” Kantor also points out that the quality of dietary supplements in the marketplace is not well monitored. There have been many cases of supplements containing impurities or not containing the actual amounts of the ingredients listed on the label. When it comes to dietary supplements, stick to bigger well-known brands such as GNC.

Side effects can include loss of appetite, stomach discomfort, mild headache, anxiety, diarrhea and nausea. There was once concern that creatine supplements could affect hydration status, heat tolerance, kidney damage and lead to muscle cramping, recent studies have discredited these concerns though it’s still suggested that those taking creatine supplements, hydrate themselves well.

The Mayo Clinic warns that those with allergies to creatine may develop asthmatic symptoms including rash, itching and shortness of breath.

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