🟢 Strong Evidence
The widespread belief that creatine supplementation damages kidney function has been definitively challenged by recent systematic evidence. A 2025 systematic review and meta-analysis published in the Journal of the International Society of Sports Nutrition examined 21 rigorous studies and found that while creatine supplementation does increase serum creatinine levels, it produces no measurable decline in actual kidney function markers. The misconception persists because doctors and patients misinterpret what rising creatinine means in the context of supplementation.
Key takeaways
- Creatine supplementation raises serum creatinine but does not impair measured kidney function, according to 21 pooled clinical trials
- The rise in creatinine reflects increased substrate production, not reduced filtration—the kidney remains healthy
- A safety review of 685 human trials involving over 26,000 participants found no credible evidence of kidney harm from creatine use
Study at a Glance
| Source | Journal of the International Society of Sports Nutrition |
| Study type | Systematic review and meta-analysis |
| Studies pooled | 21 clinical trials |
| Population | Healthy participants receiving creatine supplementation |
| Primary outcome | Serum creatinine, measured GFR, cystatin C, proteinuria |
Creatine and Kidney Function: The Lab Values Tell the Story
Mean changes from pooled meta-analysis of 21 studies; only serum creatinine increased, while all true markers of kidney health remained unchanged
Source: 2025 Systematic Review and Meta-Analysis | Journal of the International Society of Sports Nutrition | Georgian Medical Journal News
The Biochemistry Behind the Misunderstanding
The myth originates from a real but misinterpreted observation. Creatine is stored in skeletal muscle primarily as phosphocreatine, an energy substrate that degrades spontaneously at a rate of approximately 2% per day. This degradation produces creatinine, a waste product filtered and excreted by the kidneys. When someone supplements creatine and increases total body creatine stores, they inevitably produce more creatinine—this is basic chemistry.
The problem lies in how clinicians interpret standard kidney function tests. Serum creatinine and estimated glomerular filtration rate (eGFR) both assume that creatinine production is constant. The eGFR equation uses creatinine as a proxy for kidney filtering capacity. When supplementation increases creatinine production without affecting the kidney’s actual filtration rate, the equation produces an artificially depressed eGFR—a mathematical artifact, not a physiological change.
What the Meta-Evidence Shows: No Kidney Damage
The 2025 meta-analysis of 21 studies published in the Journal of the International Society of Sports Nutrition demonstrates that true markers of kidney health remain unchanged despite the rise in serum creatinine. Researchers found that creatine supplementation was associated with a mean increase in serum creatinine of 0.07 micromol/L—a small but statistically significant change. However, there were no measurable changes in measured glomerular filtration rate, cystatin C (an alternative marker of kidney function), proteinuria (protein in urine), or albuminuria (albumin in urine). These four markers reflect actual kidney function independent of creatinine metabolism.
The practical implication is straightforward: the creatinine rose because the substrate supply increased, not because the kidney became less efficient at filtering. As the source report states it, creatinine production increased “at the same filtration rate.”
A systematic review of 21 controlled trials found that creatine supplementation raised serum creatinine by 0.07 micromol/L but produced no changes in measured glomerular filtration rate, cystatin C, proteinuria, or albuminuria—the actual markers of kidney health.
— 2025 Systematic Review and Meta-Analysis, Journal of the International Society of Sports Nutrition
The Largest Safety Registry: 26,000 Participants, Zero Evidence of Harm
The largest safety analysis of creatine supplementation to date, conducted by Kreider et al. and published in 2025, reviewed 685 human clinical trials involving more than 26,000 total participants. This analysis represents the most comprehensive evidence base on creatine safety in the published literature. Across this enormous dataset, no credible evidence emerged of kidney damage attributable to creatine supplementation. This finding aligns with and substantially reinforces the clinical trial evidence on dietary supplement safety.
The persistence of the kidney-damage myth despite this evidence suggests a communication gap between research and clinical practice. Many physicians and patients rely on outdated information or misinterpret laboratory results without understanding the biochemistry underlying them.
What this means
Frequently asked questions
Does creatine supplementation actually raise creatinine levels?
Yes. According to the 2025 meta-analysis, serum creatinine increases by a mean of 0.07 micromol/L in people taking creatine supplements. This occurs because creatine stored in muscle degrades into creatinine at a higher rate when total body creatine stores increase. However, this increase reflects more substrate production, not reduced kidney filtration.
Why don’t doctors use cystatin C instead of creatinine to assess kidney function in supplementing patients?
Cystatin C is an alternative marker of glomerular filtration rate that does not depend on muscle metabolism and is unaffected by creatine supplementation. It is less commonly used in routine practice because it is more expensive and less standardized across laboratories. However, if a patient taking creatine supplements has an elevated creatinine, requesting a measured GFR or cystatin C can provide clarity about true kidney function.
Are there any populations for whom creatine supplementation poses a kidney risk?
The large safety review by Kreider et al. focused on healthy participants. People with pre-existing kidney disease should consult their nephrologist before supplementing, as their reduced filtration capacity may warrant caution. However, the evidence reviewed covered over 26,000 healthy individuals with no credible evidence of renal harm, even in long-term supplementation studies.
The creatine-kidney myth persists despite overwhelming evidence to the contrary, illustrating how laboratory findings can be misinterpreted when the underlying biochemistry is not fully understood. As clinicians and patients become more familiar with the distinction between serum creatinine elevation and actual kidney dysfunction, this misconception should gradually fade from both medical and public discourse. For now, the data are clear: creatine supplementation raises creatinine levels but does not damage kidney function in healthy individuals.
Source: Kreider et al., 2025, Journal of the International Society of Sports Nutrition
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