Creatine Long-Term Safety: How Long Studies Lasted and What They Found
How long creatine studies lasted, who was studied, what health markers were checked, what reviews concluded, and where the evidence stops, including rare case reports and unanswered questions.
Content last updated . This page has not been medically reviewed.
Quick answer
For creatine monohydrate, the longest human studies described in the reviews we read lasted up to about 5 years, and they reported no clinically important harm in the people and markers studied. A 2017 position stand from a sports nutrition society concluded that supplementation "up to 30 g/day for 5 years" was safe and well tolerated in healthy people and some patient groups. [1] That statement comes from authors with industry ties, covers monohydrate only, and is not a guarantee for any individual. This page is information only; amounts below are amounts used in studies, not advice. A clinician or pharmacist can say what suits a person.
How the evidence is labeled
Evidence in adequately nourished people means trials in people with no deficiency. Mixed means studies disagree. Insufficient evidence means too little to say. Proper evidence not found means we looked and found nothing usable.What the long studies looked at
We read these through review articles, not the original papers, so details such as group size come only from what the reviews reported.| Population | Amount used in the study | Length | What was checked and found | Source |
|---|---|---|---|---|
| American college football players | 5 to 10 g/day | 21 months | No significant effect on creatinine or creatinine clearance [1] | Position stand, 2017 |
| Healthy athletes | up to 10 g/day | 10 months to 5 years | No effect on creatine clearance or glomerular filtration rate versus controls [1] | Position stand, 2017 |
| Professional basketball players | 5 g/day | three competitive seasons | No clinically significant changes in health markers or side effects [1] | Position stand, 2017 |
| People with type 2 diabetes | not stated here | 12 weeks | No effect on kidney function [1] | Position stand, 2017 |
| Female-only studies, ages 16 to 67 (29 studies, 951 people) | 1 to 30 g/day | 4 days to 365 days | No deaths or serious adverse events reported [2] | Review, 2025 |
| Adolescents and active youth (5 studies) | varied | not stated in the abstract | No serious adverse events attributed to creatine [3] | Systematic review, 2026 |
| Healthy people and people with chronic kidney disease (26 trials, 1036 people) | varied | varied | Blood creatinine rose; authors judged this likely altered creatinine handling, not kidney injury [4] | Meta-analysis, 2026 |
Label: evidence in adequately nourished people for the athlete rows; mixed to insufficient evidence for patient groups and youth because of few studies. The adolescent review itself calls for larger studies with longer follow-up. [3]
What reviewers concluded
- The position stand said the only consistently reported side effect was weight gain. [1]
- It also said adverse event reports for supplements, including in children, rarely mentioned creatine and showed no consistent pattern. [1]
- A 2021 review of common concerns said that after more than 20 years of research with no adverse kidney effects at recommended amounts, the kidney concern still persists. [5]
- A 2026 review of kidney disease says concerns persist for people with impaired kidney function. [6] Even the position stand notes some suggest people with existing kidney disease see a physician first, as a precaution. [1]
Limits and uncertainty
- Beyond 5 years: Proper evidence not found. The reviews we read describe no human safety study longer than the periods in the table, and our PubMed searches found none.
- Rare case reports exist. One report describes a 17-year-old who developed acute kidney injury after a 6-day high-dose loading regimen. [7] A single case cannot show cause, but it is why youth, kidney and hydration questions go to a clinician. See warning signs.
- Pregnancy: direct randomized trials of safety in human pregnancy are not available. [2]
- Children and teens: the position stand considered supervised use in young athletes acceptable; it also notes label advisories against use under 18. [1] The 2026 youth review asks for more data. [3]
- Heat and cramps: a systematic review found no evidence that creatine hinders heat loss or fluid balance. [8]
- Product quality is separate from ingredient safety; see contamination and sport supplements.
Who should ask a clinician first
Anyone with kidney or liver disease, taking regular medicines, pregnant or breastfeeding, a teen, or having surgery should ask first. See medicines, kidney questions, side effects and the creatine overview. For supplements before surgery see supplements before surgery.Frequently asked questions
Is creatine safe long term?
Studies lasting up to about 5 years reported no clinically important harm in the people studied, but the reviewers have industry ties and not everyone was studied. [1]
How long have people been studied?
Up to about 5 years in the longest studies reviewed. [1] Proper evidence not found for longer.
Does creatine hurt the kidneys over time?
A 2026 meta-analysis found blood creatinine rose without change on a direct filtration measure. [4] People with kidney disease should ask first. [6]
Is long-term creatine safe for teens?
The evidence is limited: five studies in a 2026 review reported no serious events but call for more. [3]
Has anyone been seriously harmed?
Rare case reports exist, such as one 17-year-old with kidney injury after high-dose loading. [7] They do not prove cause.
References
- Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr 2017 (full text read via PMC5469049; prepared at the request of the Council for Responsible Nutrition and the ISSN; several authors declare industry ties). Read 2026-10-23.
- Antonio J, Brown AF, Candow DG, et al. Part II. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2025 (narrative review, full text read via PMC11703406; several authors declare creatine-industry ties). Read 2026-10-23.
- Rubinchuk A, Dulkoski Z, Persaud NA, Wallen M. Evaluating the Safety of Creatine Monohydrate in Adolescents: A Systematic Review of Renal, Hepatic, and Cardiometabolic Outcomes. Cureus 2026 (abstract read). Read 2026-10-23.
- de Souza Almeida A, da Silva LOD, Takahasi BNA, et al. Impact of creatine supplementation on kidney health: a systematic review and meta-analysis. Int Urol Nephrol 2026 (abstract read). Read 2026-10-23.
- Antonio J, Candow DG, Forbes SC, et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2021 (narrative review, full text read via PMC7871530; several authors declare creatine-industry funding or advisory roles). Read 2026-10-23.
- Pereira JP, Leal VO, Trigueira P, et al. Creatine supplementation in patients with kidney disease - harm or benefit? Nephrol Dial Transplant 2026 (narrative review, abstract read). Read 2026-10-23.
- Filler G, Maung E, Diaz Gonzalez de Ferris ME, et al. Acute kidney injury with cast nephropathy following creatine loading in a 17-year-old. Pediatr Nephrol 2025 (single case report, abstract read). Read 2026-10-23.
- Lopez RM, Casa DJ, McDermott BP, et al. Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses. J Athl Train 2009 (abstract read). Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.