Effect of creatine supplementation on kidney function: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of clinical intervention studies
PubMed 41199218 · doi:10.1186/s12882-025-04558-6
What was done
Systematic review and random-effects meta-analysis of literature published between January 2000 and March 2025 assessing the effect of creatine monohydrate supplementation on kidney function. The primary outcomes evaluated were serum creatinine levels and glomerular filtration rate (GFR), with subgroup analyses performed across supplementation durations.
What was found
Twenty-one studies met inclusion criteria for the systematic review, and 12 studies (177 creatine participants, 263 control participants) were pooled for the meta-analysis of serum creatinine. Creatine supplementation was associated with a small, statistically significant increase in serum creatinine (MD: 0.07 µmol/L; 95% CI: 0.01 to 0.12; p = 0.03). Subgroup analyses by duration showed a statistically significant creatinine increase in interventions lasting ≤ 1 week (MD: 0.12 µmol/L; 95% CI: 0.03 to 0.21) and > 12 weeks (numerical values not reported in abstract), but not in studies lasting 1 to 12 weeks (MD: 0.04 µmol/L; 95% CI: -0.09 to 0.17). Meta-analysis demonstrated no statistically significant difference in GFR between creatine and control groups (numerical estimates and confidence intervals not reported in abstract).
Why it matters
This review helps clarify that observed increases in serum creatinine during creatine use likely represent benign metabolic conversion to creatinine rather than true nephrotoxicity, given the absence of measurable GFR impairment.
Limits
The total pooled sample size was relatively small (440 participants across 12 analyzed trials). The abstract omits numerical values, effect sizes, and confidence intervals for GFR outcomes and the > 12-week creatinine subgroup. Details on specific GFR measurement methods (measured vs. estimated) and baseline renal health of the participants were not reported in the abstract.