Study
Effect of creatine supplementation on kidney function: a systematic review and meta-analysis
Pooling 12 studies with 177 creatine and 263 control participants, creatine raised serum creatinine by 0.07 (95% CI 0.01 to 0.12, p = 0.03) while glomerular filtration rate showed no significant change.
Elham Kabiri Naeini and colleagues searched PubMed, Scopus, Web of Science and Google Scholar for human studies published from January 2000 to March 2025. Twenty-one studies entered the systematic review. Twelve entered the serum-creatinine meta-analysis, covering 177 creatine-group and 263 control participants. Five studies covering 69 creatine and 74 control participants were pooled for glomerular filtration rate. Included designs were RCTs, non-randomised trials, cohorts, case-control and pre-post studies. A random-effects model was used.
Doses across included studies ran from 5 g/day to 20 g/day, with weight-based regimens at 0.03 to 0.3 g/kg/day. Follow-up ranged from 5 days to a mean of 2.9 years in one football-player cohort. Populations included healthy sedentary men, football players, postmenopausal women, army volunteers and adults over 45 with type 2 diabetes.
Serum creatinine rose slightly with creatine: mean difference 0.07, 95% CI 0.01 to 0.12, p = 0.03, I-squared = 69.73%. The increase was significant at follow-up of 1 week or less (MD 0.12, 95% CI 0.03 to 0.21) and not significant between 1 and 12 weeks (MD 0.04, 95% CI -0.09 to 0.17). Glomerular filtration rate showed no significant change (I-squared = 33.17%). The authors describe the creatinine rise as small, modest and transient, and a marker artefact rather than kidney damage.
However, researchers and clinicians should interpret elevated serum creatinine levels in the context of supplementation with caution and consider more specific renal function markers for accurate assessment.
The abstract does not report units for the 0.07 mean difference consistently, and the paper does not give an exact effect estimate, confidence interval or p-value for the GFR outcome, so the reassuring GFR result is stated but not quantified. Heterogeneity for serum creatinine was substantial (I-squared = 69.73%). The pool mixes RCTs with observational and pre-post designs, which carry confounding and selection bias. Most trials were small, single-centre and short; the authors state long-term safety data beyond one year remain sparse. Most trials did not report the creatinine assay type or calibration method, which may itself explain part of the heterogeneity. Methodological reporting was often missing, including sequence generation, allocation concealment, dropouts and trial registration. Funnel plots showed asymmetry for both outcomes, though trim-and-fill did not change the pooled results. No participants with pre-existing kidney disease are represented in a way that supports safety claims for that group. No funding; authors declare no competing interests.
Cited by
1 encyclopedia entries reference this study.