Creatine, a common component of many sports supplements, has a reputation for causing gastrointestinal distress. Taken properly, however, it should not result in diarrhea.
Creatine occurs naturally in the human body and is present in foods such as seafood and beef, according to Cleveland Clinic. Some people take supplements to offset age-related muscle and cognitive losses. Creatine is also a laboratory-created chemical found in many sports supplements sold in the U.S. and is popular with athletes, particularly those engaged in high-intensity sports.
Creatine Side Effects
According to a meta-analysis published in June 2020 that reviewed the side effects of creatine supplements, symptoms that were gastrointestinal (GI) in nature were the most commonly reported side effects. These include symptoms such as nausea, vomiting, diarrhea, bloating, and indigestion. However, after comparing the side effects of study participants who received a placebo instead, the study authors found no evidence that creatine supplements have a significant effect on GI symptoms.
In addition to the risk of diarrhea, creatine use has been anecdotally linked to health issues, such as muscle cramps, liver problems, and kidney dysfunction. However, these reports appear to be isolated and have not been corroborated by well-controlled studies, according to a review published in December 2024.
This same review noted that athletes and those who are physically active who supplement with creatine benefit from its water-attracting (osmotic) properties, which may help athletes stay hydrated for increased strength, endurance, and resistance to fatigue.
“We all have a store of creatine in our muscles that helps supply our muscles with energy, called ATP,” says Will Bulsiewicz, MD, a gastroenterologist in Mount Pleasant, South Carolina. “People who regularly consume creatine find they store more water in their muscles, provided they are hydrating adequately.”
It is this osmotic attribute of creatine, though, that can lead to gastrointestinal distress. Creatine draws water into whatever space it occupies, which includes muscles but also the bowel.
“If you take creatine as directed, you really should not have creatine-associated diarrhea,” Dr. Bulsiewicz says. He says this includes taking the right dose.
“The problem occurs when people load up on creatine,” says Bulsiewicz. “Often, when they are just starting a regimen of creatine supplementation, people will take up to four times the amount indicated.” This can lead to extra water in the intestine, which can cause diarrhea.
Short-term creatine-related diarrhea should not be a big problem. However, if you have diarrhea that lasts for more than two days without improvement, you should seek medical attention, according to Mayo Clinic. To help ease symptoms and cope with diarrhea, Mayo Clinic recommends drinking clear liquids such as water, broth, and juice, as well as avoiding foods that can make diarrhea worse, such as foods that have lots of fat, fiber, or seasoning.
What’s a Safe Dose of Creatine?
It is not uncommon for people to use a larger-than-usual dose, or loading dose, for the first five to seven days, according to the Office of Dietary Supplements (ODS). The typical loading dose for both men and women is 20 grams (g) per day, split into four doses. A maintenance phase follows with a dose of 3 to 5 g per day.
A loading phase isn’t always necessary and may lead to side effects because of the higher dose, according to Cleveland Clinic. Taking the recommended daily dose of 3 to 5 g per day is a safer way to increase your creatine levels, says Cleveland Clinic, though it does take longer to reach a level of creatine saturation.
The ODS considers creatine to be safe for healthy adults to take on a short-term basis and says evidence suggests that taking creatine for several years is also safe. Side effects of creatine supplements are uncommon, according to the NIH, and can likely be minimized by staying hydrated.
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