Creatine and kidney function: what the evidence says
Summary
What is it? A look at whether creatine harms the kidneys. The main source is a 2025 systematic review and meta-analysis of 21 studies, 12 of which reported data that could be pooled [1]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 meta-analysis pools the results of many studies into one overall estimate.
Why would I need it? Creatine raises the level of serum creatinine in the blood. Doctors use this level to judge the kidneys, so a blood test can make a creatine user look as if they have a kidney problem. The question is whether the rise means real harm.
Is it useful? Creatine raised serum creatinine a little, and it did not change the glomerular filtration rate (GFR), the direct measure of how well the kidneys filter [1]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 authors conclude that creatine is likely safe for the kidneys of healthy people at usual doses [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. Two limits matter. The studies were small, short and mostly rated "some concerns" for risk of bias [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. And almost none of the people had kidney disease, so the result does not show that creatine is safe for them [2]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.
FAQ
Does creatine damage the kidneys? In this meta-analysis it did not: GFR showed no significant change in 5 studies (69 people on creatine, 74 controls) [1]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 reached the same conclusion [2]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.
Why does creatine raise serum creatinine? Creatinine is a waste product made from creatine. The body turns about 2% of its creatine into creatinine each day, so more creatine means more creatinine in the blood, without any harm to the kidneys [2]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. The 2025 authors say the same [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
How big is the rise? Small: a mean difference of 0.07 (95% CI 0.01 to 0.12, p = 0.03) over controls in 14 comparisons [1]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 abstract gives the unit as µmol/L, and the main text gives no unit. A rise of 0.07 µmol/L would be too small to measure, so the unit is probably wrong in the abstract. Read the number only as "small" [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
Does the rise go away? Not clearly. The abstract calls it "transient", but the rise was significant again in studies longer than 12 weeks [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
Can I take creatine if I have kidney disease? This review cannot tell you. Only one included study had a group with a chronic disease that puts the kidneys at risk: 25 adults over 45 with type 2 diabetes [1 Table 1]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 says the evidence for people with kidney disease is very limited, and that people with very low kidney function should avoid creatine [2]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. Ask a doctor first.
Should I get my kidneys tested if I take creatine? If a test uses serum creatinine alone, it can read too high in a creatine user. The 2025 authors advise using more specific markers [1]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 names cystatin C and urine tests for blood cells, albumin and protein [2]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.
Article
What was studied
The authors searched PubMed, Scopus, Web of Science and Google Scholar for studies from January 2000 to March 2025. They included randomized trials, other trials and observational studies in people of any age or health, with any dose and form of creatine taken by mouth. They found 21 eligible studies. Twelve, with 14 comparisons for creatinine and 5 studies for GFR, had the numbers needed for pooling [1]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 review was not registered ("Clinical trial number: not applicable") [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
| Group | Studies in Table 1 |
|---|---|
| Healthy adults, young and sedentary or active | 7 |
| American football players | 2 (both observational) |
| Postmenopausal women | 1 |
| Adults over 45 with type 2 diabetes | 1 |
| Army volunteers | 1 |
Source: [1 Table 1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. Table 2 lists 10 randomized trials and 2 observational studies [1 Table 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.
What the evidence says
Serum creatinine
The meta-analysis pooled 14 comparisons: 177 people took creatine and 263 were controls. Creatine raised serum creatinine by a mean of 0.07 (95% CI 0.01 to 0.12; p = 0.03) [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. Results differed a lot between studies (I² = 69.7%; a value above 50% means the studies disagree a lot) [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
| Length of follow-up | Mean difference (95% CI) | Significant? |
|---|---|---|
| Up to 1 week | 0.12 (0.03 to 0.21) | Yes |
| 1 to 12 weeks | 0.04 (-0.09 to 0.17) | No |
| More than 12 weeks | not given in the text | Yes, according to the authors |
Source: [1]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 authors explain the early rise as a quick change in creatine and creatinine levels, and the later rise as a steady higher turnover of creatine. They think neither shows kidney damage [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. This explanation is the authors' view. The review did not test it.
Glomerular filtration rate
Five studies measured GFR before and after: 69 people on creatine and 74 controls. The pooled difference was not significant [1]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 text gives no number and no confidence interval for it. The heterogeneity was moderate (I² = 33.2%) [1]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 GFR studies included both estimated GFR (from blood markers) and directly measured GFR [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025. Measured GFR is the more exact test, and a narrative review of controlled trials describes studies that used it and found no difference between creatine and placebo, for example in older adults with type 2 diabetes [2]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.
Doses and lengths in the studies
| Study | People | Creatine | Length |
|---|---|---|---|
| Gualano 2008 | 9 vs 9, healthy sedentary men | 0.3 g per kg a day for 1 week, then 0.15 g per kg a day | 12 weeks |
| Mihic 2000 | 15 vs 15, healthy adults | 20 g a day | 5 days |
| Gualano 2011 | 13 vs 12, adults over 45 with type 2 diabetes | 5 g a day | 12 weeks |
| Domingues 2020 | 14 vs 15, healthy adults | 20 g a day for 1 week, then 5 g a day | 8 weeks |
| Kreider 2003 | 54 football players vs 44 controls | 0.1 g per kg a day | 0 to 21 months, in three groups |
| Mayhew 2002 | 10 football players vs 13 | 5 to 20 g a day | on average 2.9 years |
Source: [1 Table 1]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 table shows 6 of the 12 studies. The studies used mostly creatine monohydrate; some do not name the form [1 Table 1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
Limits of this evidence
- Small and short studies. Most were small, single-centre trials of short to medium length. There is little data beyond one year [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
- Risk of bias. Ten randomized trials were rated "some concerns", mainly because the reports did not say how people were assigned or how dropouts were handled. The two observational studies were rated moderate risk [1 Table 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.
- Possible publication bias. Funnel plots for both outcomes were uneven, which can mean that small studies with no effect were not published. A trim-and-fill check did not change the result [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
- Different blood tests. Creatinine tests differ in how much creatine disturbs them. Most trials did not report which test they used, so the review could not check this [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
- Few people with kidney disease. A narrative review names this as a main gap. It also notes that few studies lasted longer than 16 weeks, and that there is little data on other forms of creatine. It also reports that one other form, creatine ethyl ester, is less stable and raises serum creatinine [2]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.
- Missing details. Dose and training status were often missing, so the review could not compare doses [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
- Numbers that do not match. The abstract says 12 studies, while the Results mention 14 and 16 sets of results. The unit of the creatinine difference is unclear. The abstract calls the rise "transient" while the subgroup result shows a rise after 12 weeks [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
- Conflicts of interest. The authors declared none [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025.
Talk to a doctor before you start a supplement, especially if you take medicines or are pregnant.
Verification
Checked on 2026-11-10. The 2025 meta-analysis and the narrative review were read in full text. The 2017 position stand was read for its passages on kidney safety. The two second sources are not fully independent: the narrative review's authors ran at least two of the included trials (Gualano 2008 and 2011), and one author reports grants, lecture fees and a seat on the advisory board of a creatine maker.
| Claim | Result | What the check found |
|---|---|---|
| Creatine raises serum creatinine a little | Verified | The narrative review reports a higher serum creatinine in the creatine groups of some trials [2]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 |
| The rise is not kidney damage | Verified | About 2% of the body's creatine turns into creatinine each day [2]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. In one trial serum creatinine rose while cystatin C stayed the same [2]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 |
| GFR does not change | Verified | Controlled trials that measured GFR found no difference [2]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. The position stand also found no compelling evidence of harm to the kidneys [3]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 |
| Creatine is likely safe for the kidneys in healthy people at usual doses | Verified | In the position stand's view, doses of 0.3 to 0.8 g per kg a day for up to 5 years caused no adverse health risk [3]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 narrative review advises up to 20 g a day [2]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 |
| Creatine is safe in clinical populations | Partly verified | Both second sources say the evidence is limited for people with kidney disease. The position stand notes that some experts advise them to ask a doctor first [3]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 narrative review says people with very low kidney function should avoid creatine [2]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 |
| The rise is significant at up to 1 week and after 12 weeks, but not between | Not verified | Neither second source reports the same split. The narrative review mentions a rise of serum creatinine at only one time point in some trials [2]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 |
| Serum creatinine alone can mislead in creatine users | Verified | The narrative review gives the same advice [2]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 |
| The rise is "transient" | Contradicted | The abstract says so, but the paper's own subgroup result shows a significant rise after 12 weeks [1]Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025 |
See also
Sources
Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. Naeini EK, Eskandari M, Mortazavi M, et al. BMC Nephrol, 2025
Meta-analysis · About this source