Creatine safety and side effects

Summary

What is it? Creatine is a compound made from amino acids that muscles use to make energy in short, hard efforts. People take it as a powder, most often as creatine monohydrate ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}.

Why would I need this page? When you want to know whether creatine causes harm, and what is known about the dose, the kidneys, dehydration and age.

Is it safe? In healthy adults, the evidence points to few problems. The 2017 position stand of the International Society of Sports Nutrition (ISSN) says that weight gain is the only side effect that studies report consistently, and that doses of 0.3 to 0.8 g per kg of body weight a day, up to 30 g a day, for up to 5 years did not cause clinically significant harm ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. This is an expert opinion, not a systematic review, and a supplement trade group paid for it ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. A 2025 meta-analysis of controlled trials found no significant change in kidney filtration ^{[2]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025}. The evidence is thinner for children, for people with kidney disease, and for very long use.

FAQ

What side effects does creatine have? Weight gain is the only side effect that the position stand lists as consistent ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. Early in a loading phase, the body holds about 0.5 to 1.0 L more water, in step with the weight gain ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. A 2021 review says this early water gain is the most common side effect, and that longer studies did not find a lasting rise in water relative to muscle mass ^{[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}.

Does creatine cause dehydration or muscle cramps? The position stand says well-controlled studies do not show more dehydration, muscle cramps, muscle injuries or stomach upset ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. A 2021 review by many of the same authors reaches the same view for dehydration and cramps ^{[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}.

Is creatine bad for the kidneys? Not in the studies so far. A 2025 meta-analysis found a small rise in serum creatinine, a waste product that the kidneys clear, and no significant change in the glomerular filtration rate (GFR), the measure of how well the kidneys filter ^{[2]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025}. A narrative review of controlled trials agrees ^{[4]Is It Time for a Requiem for Creatine Supplementation-Induced Kidney Failure? A Narrative Review. Longobardi I, Gualano B, Seguro AC, et al. Nutrients, 20231 author declares ties to industry}. Few of the people had kidney disease. See Creatine and kidney function: what the evidence says.

Is creatine safe for children and teenagers? The evidence is limited. The ISSN says it is acceptable for young athletes in supervised, competitive training who keep to recommended doses, and that label warnings for people under 18 are probably not needed ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. A 2021 review calls the evidence limited and says it appears safe and possibly helpful ^{[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}. Both reviews share authors, and no independent safety trial in children was found.

Are other forms of creatine safer? No. The position stand says other forms have no proven advantage over monohydrate ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}, and a 2022 systematic review found no consistent gain from them over placebo and few trials against monohydrate ^{[5]Efficacy of Alternative Forms of Creatine Supplementation on Improving Performance and Body Composition in Healthy Subjects: A Systematic Review. Fazio C, Elder CL, Harris MM. J Strength Cond Res, 2022}.

Article

What the position stand is

The 2017 ISSN position stand is a long narrative review. A narrative review does not use a fixed search method, so its authors choose the studies. The authors write the official position of the ISSN. The Council for Responsible Nutrition, a trade group of supplement makers, paid for the work. Several authors report grants from, consulting for, or jobs at companies that sell creatine ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. The position stand is therefore useful as a summary of what a group of experts believes, and weaker as proof.

What it says about safety

The position stand also says that some case reports of high creatinine or kidney problems in people who took creatine had no careful check of the cause. It adds that rats with kidney cysts did worse on very high doses of creatine ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}.

Doses used

The position stand describes loading, about 0.3 g per kg of body weight a day for 5 to 7 days, then 3 to 5 g a day to keep the stores full. A slower plan is 3 g a day for 28 days ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry}. A 2021 review describes the same plan ^{[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}.

Limits of this evidence

1. The main source is an opinion paper paid for by a trade group, and its second source shares authors with it ^{[1]International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Kreider RB, Kalman DS, Antonio J, et al. J Int Soc Sports Nutr, 2017Paid for by industry7 authors declare ties to industry[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}.
2. We found no second source for the claim of 5 years of use at high doses. Few people in the kidney meta-analysis had kidney disease ^{[2]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025}.
3. A 2021 review calls the evidence in children limited ^{[3]Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. Antonio J, Candow DG, Forbes SC, et al. J Int Soc Sports Nutr, 20219 authors declare ties to industry}.
4. Creatine raises serum creatinine a little because the body turns about 2% of creatine into creatinine each day. A blood test that uses serum creatinine alone can read too high ^{[4]Is It Time for a Requiem for Creatine Supplementation-Induced Kidney Failure? A Narrative Review. Longobardi I, Gualano B, Seguro AC, et al. Nutrients, 20231 author declares ties to industry}.

Talk to a doctor before you start a supplement, especially if you take medicines or are pregnant.

Verification

Checked on 2026-11-10. The 2017 position stand and the 2021 ISSN review were read in full text, and the 2022 review of other forms as an abstract. The other sources were read for the main creatine page. The two ISSN papers share authors (J. Antonio, D. G. Candow, R. B. Kreider, T. N. Ziegenfuss) and do not check each other.

See also

• Creatine
• Creatine and kidney function: what the evidence says