context: In their quest to run farther, jump higher, and outlast the competition, many athletes have turned to a variety of performance-enhancing drugs and supplements. Creatine is the most popular of these substances, believed to enhance muscle mass and help athletes achieve bursts of strength. var s_context; s_context= s_context || {}; s_context['wb.modimp'] = 'vidfloat'; if(webmd.useragent && webmd.useragent.ua.type === 'desktop'){ webmd.ads2.disable Initial Load(); webmd.ads2.disable Ads Init = true; $(function() { webmd.p.pim.increment(); $('.responsive-video-container').insert After('.module-social-share-container'); require(['video2/1/responsive-player/video-loader'], function(video Loader) { video Loader.init({ autoplay: webmd.useragent.ua.type === 'desktop' && ! !s_sensitive, chron ID: $('article embeded_module[type=video][align=top]:eq(0)').attr('chronic_id'), continuous Play: true, cp Options: { flyout: true }, display Ads: true, mode: 'in-article', sticky: true }) }); }); } else { $(function(){ $('.responsive-video-container').remove(); }); } Part of the reason for creatine's popularity might be its accessibility. Creatine powder, tablets, energy bars, and drink mixes are available without a doctor's prescription at drug stores, supermarkets, nutrition stores, and over the Internet. Although creatine is a natural substance, it hasn't been well-studied over the long term. Researchers still aren't sure what effects it might have on the body, although there is evidence that in the short term, creatinine is safe for high-intensity resistance training. Creatine is a natural substance that turns into creatine phosphate in the body. Creatine phosphate helps make a substance called adenosine triphosphate ( ATP). ATP provides the energy for muscle contractions. The body produces some of the creatine it uses. It also comes from protein-rich foods such as meat or fish. Back in the 1970s, scientists discovered that taking creatine in supplement form might enhance physical performance. In the 1990s, athletes started to catch on, and creatine became a popular sports supplement. The supplement is particularly popular among high school, college, and professional athletes, especially football and hockey players, wrestlers, and gymnasts. Creatine is thought to improve strength, increase lean muscle mass, and help the muscles recover more quickly during exercise. This muscular boost may help athletes achieve bursts of speed and energy, especially during short bouts of high-intensity activities such as weight lifting or sprinting. However, scientific research on creatine has been mixed. Although some studies have found that it does help improve performance during short periods of athletic activity, there is no evidence that creatine helps with endurance sports. Research also shows that not everyone's muscles respond to creatine; some people who use it see no benefit. Despite the popularity of creatine among young people, there has been very little research conducted in children under age 18. Of those studies, a few have suggested a positive effect but the overall evidence is inconclusive. In one study, teenage swimmers performed better after taking creatine; in another study, it helped high school soccer players sprint, dribble, and jump more effectively. Researchers are studying whether creatine might also be useful for treating certain health conditions caused by weakened muscles, including: Heart failure and heart attack Huntington's disease Neuromuscular disorders, including muscular dystrophy and amyotrophic lateral sclerosis ( ALS or Lou Gehrig's disease) Creatine is also being studied as a way to lower cholesterol in people with abnormally high levels. Although early research has been promising, it's too early to say for sure whether creatine is effective for any of these conditions. Just because creatine is natural, doesn't necessarily mean that it is safe. Supplements aren't held to the same standards by the FDA as medications, which means you can't always know exactly what's in your supplement, or in what amounts. Researchers still don't know the long-term effects of taking creatine supplements, especially in young people. Adolescents who take creatine often do so without their doctor's advice, which can cause them to take more than the recommended dose. Although most healthy people can take it with no problem, creatine can, in rare cases, have adverse effects, particularly when used in excess. Side effects can include: Weight gain Anxiety Breathing difficulty Diarrhea Fatigue Fever Headache Kidney problems Nausea, vomiting Rash Stomach upset Certain drugs, including diabetes medications, anti-inflammatories like ibuprofen and naproxen, and diuretics, can have dangerous interactions with creatine. Taking the stimulants caffeine and ephedra with creatine can increase the risk of side effects. Creatine isn't recommended for people with kidney or liver disease, or diabetes. Others who should avoid taking it are children under age 18 and women who are pregnant or nursing. Also don't use creatine if you are taking any medication or supplement that could affect your blood sugar, because creatine may also affect blood sugar levels. If you do take creatine, drink enough water to prevent dehydration. No matter how healthy you are, let your doctor know before you take creatine or any other supplement.