Does Creatine Damage Your Kidneys? What the Evidence Actually Shows

The claim that creatine damages kidneys is one of the most persistent myths in sports nutrition. It has survived for nearly three decades despite being contradicted by every systematic review ever published on the topic. As of mid-2026, there are now five independent meta-analyses examining creatine's effect on kidney function. Not one has found evidence of renal damage.

The myth persists for a specific, identifiable reason: creatine raises a lab marker that doctors use to estimate kidney function. If you do not understand why that marker goes up, and what it does and does not tell you, the blood work looks alarming. This article explains the mechanism, reviews all five meta-analyses, and covers the situations where genuine caution is warranted.

The Creatinine Problem

Creatine, the supplement, is metabolized in muscle tissue into creatinine, a waste product. The kidneys filter creatinine out of the blood and excrete it in urine. For decades, doctors have used serum creatinine levels as a proxy for kidney function, higher creatinine generally means the kidneys are filtering less efficiently.

The problem: supplementing with creatine increases creatinine production directly. More creatine going in means more creatinine coming out. Serum creatinine rises not because the kidneys are struggling, but because there is simply more creatinine being produced. The kidneys are doing their job normally. There is just more of it to do.

This is not a subtle distinction. It is the entire basis of the myth. Every concerned Reddit post, every cautious doctor, every alarming blood test result in a creatine user, almost all of them trace back to this single measurement artifact.

The Gold Standard Test

The question is not whether creatinine goes up with creatine supplementation. It does. That is expected, benign, and well-documented. The question is whether actual kidney filtration capacity (glomerular filtration rate (GFR)) changes.

GFR can be estimated from creatinine (eGFR), but that estimate is confounded by the very thing we are trying to evaluate: if creatinine is elevated for non-renal reasons, the creatinine-based eGFR will underestimate kidney function. It will look like the kidneys are worse than they actually are.

The clean test uses an external marker, Cr-EDTA, inulin, or cystatin C, that is not affected by creatine supplementation. These markers measure actual filtration rate without the confound. And this is where the 2026 meta-analysis made its most important contribution.

Five Meta-Analyses at a Glance

The Five Meta-Analyses

1. de Souza e Silva et al. (2019), Journal of Renal Nutrition

An early dedicated meta-analysis pooled controlled trials and found no meaningful changes in markers of kidney function during creatine supplementation (PMID: 42035842). Sample size was limited (6 studies in quantitative analysis), but the direction was clear: no signal of renal harm.

2. Naeini et al. (2025), BMC Nephrology

The study that established the framework used throughout this article. Twenty-one studies in systematic review, twelve in meta-analysis (177 creatine users, 263 controls). Key result: creatine supplementation produced a small but statistically significant increase in serum creatinine (MD: 0.07 µmol/L). Critically, GFR showed no significant change (PMID: 41199218).

The authors concluded: "Creatine supplementation is associated with a modest, transient increase in serum creatinine levels, likely due to metabolic turnover rather than renal impairment."

Subgroup analysis by duration revealed an interesting pattern. The creatinine increase was significant in the first week (loading phase), disappeared from weeks 1-12, and became significant again after 12 weeks. This suggests the body partially adapts to the additional creatinine load over time but reaches a new steady state with long-term use. At no point did GFR change.

3. Tsiaras et al. (2026), Journal of Renal Nutrition

Published April 2026 in the Journal of Renal Nutrition, a nephrology journal, notably, not a sports medicine journal. This meta-analysis of RCTs confirmed no adverse effects of creatine supplementation on kidney function and added the clinical context of responsible supplementation guidelines (J Renal Nutrition, 202600082-8/abstract)).

4. de Souza Almeida et al. (2026), International Urology and Nephrology

Published July 2026, this is the most comprehensive meta-analysis to date: 26 RCTs, 1,036 participants. It is also the first to do something that should have been done years ago: stratify GFR results by measurement method (PMID: 42507286).

The results split cleanly along methodological lines:

• Serum creatinine: Significantly increased (MD: 0.14 mg/dL; 95% CI: 0.05-0.22; P =.002). Expected. Not concerning.
• GFR by creatinine-based methods (eGFR): Appeared to decrease (MD: -10.75 mL/min; 95% CI: -17.48 to -4.02; P =.002). This looks alarming: a 10.75 mL/min drop would be clinically significant. But wait.
• GFR by Cr-EDTA (gold standard, not confounded by creatinine): No significant change. Actual kidney filtration was preserved.

This is the cleanest demonstration of the creatinine artifact to date. When you measure kidney function using a marker that creatine supplementation inflates, function looks worse. When you measure it using a marker that is independent of creatine metabolism, function is unchanged.

The authors explicitly stated that this was the first meta-analysis to "rigorously stratify glomerular filtration rate results by measurement method, effectively isolating methodological artifacts from true kidney injury."

Creatinine vs Actual Kidney Function: The Key Distinction

The 1998 Case That Started It

The kidney myth has an origin story, and it is worth telling because it illustrates how a single case report can create a medical myth that outlasts decades of contradictory evidence.

In 1998, Pritchard and Kalra published a letter in The Lancet describing a 25-year-old male whose renal function worsened while taking creatine (PMID: 9643752). The patient had pre-existing focal segmental glomerulosclerosis, a kidney disease that causes progressive scarring and impairment regardless of what supplements you take.

One patient. Pre-existing kidney disease. Published in a high-impact journal. And from there, the warning propagated through medical education, clinical practice, and popular culture for the next 28 years.

Five meta-analyses later, the evidence is unambiguous: the general warning was not justified by the original case, and it has not been supported by any controlled research since.

The ISSN Position

The International Society of Sports Nutrition has issued two major position stands on creatine: Kreider et al. (2017) and the 2026 update by Kerksick et al. Both conclude that creatine supplementation is safe and well-tolerated in healthy individuals across short-term loading (up to 20 g/day for 5–7 days) and long-term maintenance (3–5 g/day for up to five years), with no evidence of adverse renal effects (PMID: 28615996; PMID: 41870601).

This is the professional organization whose members are researchers and clinicians specializing in sports nutrition. Their consensus, based on reviewing over 500 studies, is that creatine is the single most effective and thoroughly studied ergogenic supplement available, and it does not hurt your kidneys.

The 685-Trial Safety Review (2025)

Kreider et al. published a separate comprehensive safety analysis in 2025, evaluating side effects reported across 685 human clinical trials on creatine supplementation and cross-referencing them with worldwide adverse event report databases. No consistent renal safety signal was identified (JISSN, 2025).

Six hundred eighty-five trials. Zero consistent signal of kidney damage.

When Caution Is Actually Warranted

The safety data (all five meta-analyses, the ISSN position, the 685-trial review) applies to people with normal kidney function. The evidence is meaningfully less clear for specific populations:

Pre-existing Chronic Kidney Disease (CKD)

The de Souza Almeida 2026 meta-analysis included some data from CKD patients, but the evidence base for this population remains thin. In CKD, the kidneys are already working below capacity. Adding any metabolic load, even a benign one, requires caution because the margin of safety is smaller.

Most nephrologists recommend avoiding creatine in CKD patients until more data is available. This is a precautionary recommendation based on limited evidence, not a finding of harm. The distinction matters: "we do not have enough evidence to confirm safety" is different from "we have evidence of danger."

Single Kidney

People with a solitary kidney (congenital, surgical, or donated) have reduced total nephron mass. The remaining kidney typically compensates by increasing its filtration capacity, but the reserve margin is narrower. No controlled creatine study has been conducted in this population. Precautionary avoidance is reasonable.

Concurrent Nephrotoxic Medications

NSAIDs (ibuprofen, naproxen), certain antibiotics (aminoglycosides, vancomycin), and some other medications can stress the kidneys directly. Adding creatine on top of nephrotoxic drugs may not cause harm, but the combination has not been studied, and there is no reason to take unnecessary risks with kidney function.

Dehydration

Creatine draws water into muscle cells through osmosis. Chronic inadequate fluid intake during creatine supplementation could theoretically concentrate the kidneys' workload. The evidence for this concern is largely theoretical, but drinking adequate water during creatine use is both prudent and effortless.

What to Tell Your Doctor

This is the single most practically useful piece of information in this article: if you take creatine, tell your doctor before any blood test.

Elevated creatinine in an unsuspecting physician's hands leads to a predictable cascade: concern, repeat testing, possibly a referral to nephrology, anxiety for the patient, and, in the worst case, unnecessary discontinuation of a supplement that was providing real benefits.

One sentence prevents all of that: "I take creatine monohydrate, 5 grams a day, which is expected to raise my creatinine level."

If your doctor wants a clean assessment of kidney function that is not confounded by creatine, they can order cystatin C-based GFR estimation. Cystatin C is a protein filtered by the kidneys that has nothing to do with creatine metabolism. It provides an accurate GFR estimate even in creatine users.

Practical Blood Work Guide for Creatine Users

If you take creatine and get regular blood work, here is exactly what to expect, what to tell your doctor, and when to actually worry:

The sentence that prevents unnecessary panic: "I take creatine monohydrate, 5 grams daily, which will raise my creatinine level. Can you order a cystatin C-based GFR if you need to assess my kidney function?"

Print that out and hand it to your phlebotomist if you do not want to have the conversation.

The 2025–2026 Meta-Analysis Update

Three meta-analyses published in 2025–2026 represent the strongest evidence base to date on creatine and kidney safety.

Naeini et al. (2025, BMC Nephrology) analyzed studies from 2000 to March 2025 and confirmed that creatine supplementation produces a small increase in serum creatinine (MD: 0.07 µmol/L), but this reflects increased creatine turnover in muscle, not kidney damage. When kidney function was measured using methods not affected by creatine metabolism (such as Cr-EDTA clearance or cystatin C), no impairment was detected (Naeini et al., 2025).

A 2026 meta-analysis (International Urology and Nephrology, 26 studies, 1,036 participants) found that creatine raised serum creatinine by 0.14 mg/dL and appeared to reduce creatinine-based eGFR by 10.75 mL/min. But when GFR was measured using Cr-EDTA clearance, there was no reduction. The authors explicitly cautioned against interpreting creatinine-based eGFR changes as evidence of kidney harm.

Neither review found increases in proteinuria, albuminuria, or urinary creatinine excretion: markers that would indicate actual kidney tissue damage.

Cystatin C: The Better Kidney Test for Creatine Users

Standard creatinine-based kidney tests (eGFR) are unreliable in people taking creatine. Cystatin C is a protein produced by all nucleated cells at a constant rate, unlike creatinine, it is not affected by muscle mass, diet, or creatine supplementation.

Cystatin C-based eGFR (eGFRcys) provides a more accurate picture of kidney function in creatine users. A combined creatinine-and-cystatin C equation (CKD-EPI 2021) is the gold standard. If your creatinine-based eGFR comes back borderline after starting creatine, asking for a cystatin C add-on resolves the ambiguity without unnecessary alarm.

Most major commercial labs offer cystatin C. The conversation with your doctor: "I take creatine monohydrate, which raises creatinine independently of kidney function. Can we add cystatin C to confirm my actual filtration rate?" The 2025 Naeini meta-analysis specifically recommended cystatin C or measured GFR as confirmatory tests.

Dose-Response and Saturation Physiology

Most safety data covers 3–5 g/day maintenance. Some athletes take 10+ g/day continuously, this dose range has very little dedicated safety data. The ISSN position stand addresses 3–5 g/day, and loading at 20 g/day for 5–7 days has been extensively studied.

The physiology is important: at 3–5 g/day, intramuscular creatine stores reach saturation within 3–4 weeks. Taking more does not increase muscle creatine beyond this saturation point: the excess is excreted as creatinine. Higher doses produce more waste with no additional benefit.

The 2026 meta-analysis found no dose-dependent worsening of kidney markers, but most studies used 3–5 g/day. The evidence supports safety at the standard dose, it does not validate substantially higher chronic dosing.

Hydration: Separating Fact From Gym Lore

A persistent myth is that creatine dehydrates you or stresses kidneys through water manipulation. The physiology says the opposite.

Creatine draws water into muscle cells (intracellular hydration), increasing body weight by 1–2 kg in weeks 1–2. This is not dehydration: total body water actually increases. A 2025 safety review (Longobardi et al., Frontiers in Nutrition) concluded that the dehydration myth is unsupported by literature. Studies measuring hydration during creatine use, including in heat stress, found no increased risk of dehydration, heat illness, or cramping.

Adequate water intake (2.5–3.5 L/day, adjusted for sweat) is standard advice for any active person, not a creatine-specific requirement.

Special Populations

Competitive Athletes

Athletes have elevated baseline creatinine and AST from training, making blood work harder to interpret. Establishing baseline values before starting creatine (and flagging creatine use on every lab order) prevents false alarms.

Older Adults (65+)

Age-related GFR decline means older adults clear creatinine more slowly. Cystatin C-based GFR should be preferred in this population. RCTs by Candow et al. have shown creatine combined with resistance training is safe and effective for maintaining muscle mass in older adults.

Single Kidney

Individuals with one functioning kidney have reduced nephron mass and compensatory hyperfiltration. No specific creatine study exists for this population. Medical oversight is warranted: not because creatine is nephrotoxic, but because the safety margin is reduced.

Adolescents

A 2026 systematic review (Cureus) evaluated creatine safety in adolescents across five studies and found no renal safety signals. The American Academy of Pediatrics recommends physician supervision for supplementation in athletes under 18, but has not issued a contraindication.

Frequently Asked Questions

Will creatine damage my kidneys?

No. Across six meta-analyses and hundreds of studies, creatine monohydrate at 3–5 g/day has not been shown to impair kidney function in healthy adults. The 2026 meta-analysis of 1,036 participants found no change in actual kidney filtration when measured by methods unaffected by creatine. Serum creatinine rises, but that is a measurement artifact.

No. Across six meta-analyses and hundreds of individual studies, creatine monohydrate at 3–5 g/day has not been shown to impair kidney function in healthy adults. The 2026 meta-analysis of 1,036 participants confirmed no changes in actual kidney filtration when measured by methods unaffected by creatine metabolism. The serum creatinine elevation caused by creatine supplementation is a measurement artifact, it reflects increased creatine turnover, not kidney damage.

My eGFR dropped after starting creatine. Should I stop?

Not necessarily. If your eGFR was calculated from creatinine, the drop is likely a mathematical artifact. Creatine raises serum creatinine, and the eGFR formula uses creatinine as its input, so the estimate falls even though true filtration is unchanged. Ask your doctor for a cystatin C-based eGFR to confirm your actual kidney function.

Not necessarily. If your eGFR was calculated using a creatinine-based formula (which most standard panels use), the drop is likely a mathematical artifact. Creatine increases serum creatinine, and the eGFR formula uses creatinine as its input, so the output (eGFR) decreases even though your actual kidney filtration rate has not changed. Ask your doctor for a cystatin C-based eGFR test to confirm your true filtration rate.

Can I take creatine with pre-existing kidney disease?

This is the one group where genuine caution applies. People with eGFR below 60 mL/min (CKD Stage 3 or higher) have reduced kidney capacity. Creatine is not nephrotoxic, but any substance that raises the kidney's excretory workload deserves oversight when function is already compromised. Consult your nephrologist before starting creatine if you have diagnosed kidney disease.

This is the one population where genuine caution is warranted. People with eGFR below 60 mL/min (CKD Stage 3 or higher) have reduced kidney capacity. While creatine is not nephrotoxic, any substance that increases the kidney's excretory workload deserves medical oversight when kidney function is already compromised. Consult your nephrologist before starting creatine if you have diagnosed kidney disease.

Does creatine cause kidney stones?

There is no published evidence linking creatine to kidney stones. Stones form from calcium oxalate, uric acid, or struvite, none of which are metabolically related to creatine. Adequate hydration, which is recommended for all creatine users, actually lowers stone risk. If you have a stone history, creatine is not contraindicated, but maintaining high fluid intake matters.

There is no published evidence linking creatine supplementation to increased kidney stone risk. Kidney stones form from calcium oxalate, uric acid, or struvite: none of which are metabolically related to creatine. Adequate hydration (which is recommended for all creatine users) actually reduces kidney stone risk. If you have a history of kidney stones, creatine is not contraindicated, but maintaining high fluid intake is important regardless of supplementation.

How much water should I drink while taking creatine?

There is no creatine-specific water requirement. The standard guideline for active adults, 2.5 to 3.5 liters of total fluid daily adjusted for sweating, applies. Creatine increases intracellular water in muscle, which is why weight rises 1–2 kg initially, but it does not cause dehydration. Drinking excessively beyond thirst cues is unnecessary.

There is no creatine-specific water requirement. The standard recommendation for active adults (2.5 to 3.5 liters of total fluid per day, adjusted upward for heavy sweating) applies. Creatine increases intracellular water retention in muscle (which is why body weight increases by 1–2 kg initially), but it does not cause dehydration. The kidneys excrete the additional creatinine, and adequate hydration supports this process. Drinking excessive water beyond thirst cues is unnecessary and can dilute electrolytes.

Is creatine safe for women?

Yes. The safety data applies equally to men and women. Women metabolize creatine through the same pathways and excrete creatinine identically. Multiple meta-analyses have included female participants without finding sex-specific safety signals. The perceived bloating concern is minor: the 1–2 kg increase is intracellular water inside muscle, not subcutaneous water that changes visible appearance.

Yes. The safety data applies equally to men and women. Women metabolize creatine through the same pathways and excrete creatinine through the same renal mechanisms. Several meta-analyses have included female participants without finding sex-specific safety signals. The concern that creatine causes "bloating" in women is largely a perception issue: the 1–2 kg weight increase from intracellular water retention occurs in muscle tissue, not subcutaneously, and does not change body composition or visible appearance in the way that subcutaneous water retention would.

Who should be cautious with creatine and kidney health?

Creatine does not harm healthy kidneys, but people with existing kidney disease should only use it under medical supervision. For healthy adults, creatine at standard doses poses no kidney risk. The groups below should get a physician's guidance, primarily because reduced kidney capacity or confounded lab readings change the calculation.

Pre-existing kidney disease. People with CKD Stage 3 or higher (eGFR below 60) have reduced excretory capacity. Creatine is not nephrotoxic, but any substance that raises the kidney's workload deserves oversight when function is already compromised.

A single functioning kidney. Those with one kidney (from donation, congenital absence, or surgery) have reduced nephron mass and compensatory hyperfiltration. No dedicated study exists for this group, so medical clearance is prudent.

Upcoming blood work without disclosure. Creatine raises serum creatinine, which can look like kidney impairment on standard panels. Always tell your doctor you take creatine so a cystatin C test can confirm true kidney function if needed.

Non-standard forms or extreme doses. Safety data covers creatine monohydrate at 3–5 g/day. Doses well above this or unstudied novel forms lack the evidence base that makes standard creatine reassuring.

The Bottom Line

Five meta-analyses. Over 1,000 participants in the most recent one. Twenty-eight years of controlled research following an overblown case report. Six hundred eighty-five clinical trials cross-referenced with adverse event databases. The ISSN position stand based on 500+ studies.

The evidence says the same thing at every level: creatine supplementation at recommended doses does not damage the kidneys of healthy adults.

Creatine does raise serum creatinine. That is a lab marker going up for a known, benign, metabolic reason, not a sign of damage. The 2026 de Souza Almeida meta-analysis demonstrated this definitively by showing that GFR measured by gold-standard methods (not confounded by creatinine) does not change.

The kidney myth is dead. It has been killed five times by five independent research groups. The only thing keeping it alive is the gap between what the published evidence says and what people remember hearing from a trainer or a doctor in 2003.

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Written by Tao Wu. This article is based on five peer-reviewed meta-analyses, the ISSN position stand, and a 685-trial safety review. YourHealthier sells creatine supplements. See our editorial policy for how we research and write.

Last updated: September 19, 2026

If you have kidney disease or take medications that affect kidney function, check with your healthcare provider before using creatine, since reduced clearance changes the calculation. Everything above is educational rather than medical advice. These statements have not been evaluated by the Food and Drug Administration, and creatine is not intended to diagnose, treat, cure, or prevent any disease.

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References

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Naeini EK, et al. Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. *BMC Nephrology*. 2025;26(1):622. PubMed: 41199218

Tsiaras A, et al. The effect of creatine supplementation on kidney function: a systematic review and meta-analysis of randomized controlled trials. *Journal of Renal Nutrition*. 2026. Link00082-8/abstract)

de Souza e Silva A, et al. Effects of creatine supplementation on renal function: a systematic review and meta-analysis. *Journal of Renal Nutrition*. 2019;29(6):480-489. PubMed: 42035842

Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation. *JISSN*. 2017;14:18. PubMed: 28615996

Kerksick CM, et al. The emerging and evolving evidence supporting creatine as an ergogenic aid. *JISSN*. 2026. PubMed: 41870601

Kreider RB, et al. Safety of creatine supplementation: analysis across 685 clinical trials. *JISSN*. 2025. Link

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Pereira JP, et al. Creatine supplementation in patients with kidney disease — harm or benefit? *Nephrology Dialysis Transplantation*. 2026. PubMed: 42545747

Naeini EK, et al. Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. *BMC Nephrology*. 2025;26(1):622. PubMed: 41199218