Is creatine safe? The supplement is popular with athletes, but should you take it?

The health benefits of creatine are many, and include strength and muscle enhancement, improved bone, brain and heart health, and help against certain neuromuscular conditions such as multiple sclerosis (MS) and muscular dystrophy. 

Despite such advantages, some myths and misunderstandings prevail concerning creatine's safety profile that experts keep working to clear up. Among the most common misconceptions is that creatine is dangerous to take as a supplement. While that can be true for some people or in very high doses, under most conditions, supplemental creatine is considered safe.  

What is creatine? 

Creatine is an amino acid that's produced in one's kidneys, liver and pancreas and is stored for strength and energy primarily in one's muscles. Beyond the natural production of the amino acid, about half the body's supply of creatine ideally comes from the foods one eats. The richest dietary sources of creatine are red meat and seafood, "so people who consume limited animal proteins, such as vegans or vegetarians, may benefit from supplementation," explains Tara Schmidt, MEd, lead registered dietitian for the Mayo Clinic Diet. 

The supplement is also extremely popular among athletes and bodybuilders because it supports muscle strength and performance, especially during exercise and other physical activity. Once a divisive topic, creatine as a dietary supplement is now considered one of the most proven dietary supplements available. 

Such supplementation is available in pill, powder or liquid form and as an energy bar.  

Is creatine bad for you?

Though creatine has gotten the aforementioned bad rap in the past, research has shown that it is safe to consume small to moderate doses of a creatine supplement daily.

Some research suggests that creatine may worsen kidney function in people who already have a kidney disorder, but other studies are mixed, and those with healthy kidneys shouldn't be harmed by creatine when taken in recommended doses, per the Mayo Clinic. At higher doses, however, the supplement has the potential for serious side effects, including kidney damage. 

When taken in excess, there is also "potential for weight gain from water retention, dizziness, nausea and vomiting, diarrhea and excessive sweating," explains Perri Halperin, MS, RD, clinical nutrition coordinator for the Mount Sinai Health System. And if taken at high doses for too long, "the body may stop making its own creatine," she adds. But again, such side effects are rare when taking the recommended dosage.

The one type of creatine that isn't known to be as safe or unsafe is its topical application form. Creatine creams are thought to have anti-aging properties, though supportive research is not robust and some topical users report redness, itching and sometimes even serious skin reactions.

Is creatine safe?

Because creatine supports one's muscles especially, it has a vital role in heart health since the heart is an organ made up almost entirely of cardiac muscle. Creatine also plays a role in heart contraction and energy metabolism. Because of these factors and numerous studies, creatine supplementation is considered safe for one's heart and has other cardiovascular benefits as well such as reducing fatigue which can help one's heart function more efficiently. 

Even still, some groups of people are cautioned against taking creatine as a supplement. "There is not enough evidence to know if it is safe in women who are breastfeeding or pregnant, or in people with diabetes, liver disease, Parkinson’s disease or bipolar disorder," explains Schmidt.

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How much creatine is considered safe?

Based on current evidence, "there is not a consensus on the upper limit of creatine intake," explains Stefany Veldhuizen, MS, RDN, LDN, registered dietitian at Northwestern Medicine at Central DuPage Hospital. "However, 2-3 grams of creatine a day in the form of creatine monohydrate is generally recognized as safe." Even doses of 5-10 grams taken daily over several years have been shown to be safe.

Regardless of one's intended dose or frequency of use, "it is always a good idea to consult your registered dietitian before starting supplements," advises Veldhuizen.