Creatine and Kidney Health: Creatinine, eGFR and What Safety Studies Show

Questions about creatine and kidney health are complicated by one laboratory fact: creatinine is both a common kidney marker and a breakdown product related to creatine metabolism. Starting creatine can increase serum creatinine, which can make a creatinine-based estimated GFR look worse even when true filtration has not changed.

That means a higher creatinine value after supplementation is not automatically kidney damage. It also does not mean kidney disease should be ignored. The correct interpretation depends on the person, baseline renal function and which filtration marker is being used.

Why creatine can raise serum creatinine

Creatine and phosphocreatine naturally degrade to creatinine. Supplementing creatine increases the body's creatine pool, so a modest increase in creatinine production is biologically plausible. Many routine eGFR equations infer kidney filtration from serum creatinine. If creatinine rises for metabolic reasons, the equation can report a lower eGFR without equivalent loss of filtration.

Almeida 2026 meta-analysis: 26 studies and multiple kidney markers

A 2026 systematic review and meta-analysis included 26 studies and 1,036 participants. It found that creatine supplementation increased serum creatinine and reduced creatinine-based eGFR. However, directly measured Cr-EDTA GFR and common kidney-damage markers such as albuminuria and proteinuria did not significantly worsen.

This distinction is central. The creatinine signal is real; the evidence did not show the same deterioration when kidney function was assessed with measures less dependent on creatinine metabolism.

What the 2025 meta-analysis found

A separate 2025 systematic review reached a similar practical conclusion: creatine caused a modest increase in serum creatinine but no significant overall change in GFR. Together, these analyses argue against diagnosing creatine-related renal injury from serum creatinine alone.

Can creatine cause kidney damage in healthy adults?

At standard studied doses, the available controlled evidence does not show a consistent kidney-damaging effect in healthy adults. That is more precise than saying creatine “cannot affect the kidneys.” Long-duration trials are less abundant than short- and medium-term studies, and people with significant pre-existing kidney disease are not the same population as healthy gym users.

Why kidney test results can appear to disagree

Kidney measure	What creatine can do	How to interpret it
Serum creatinine	Can increase modestly	Creatinine is a creatine breakdown product, so a rise is not automatically evidence of structural kidney injury.
Creatinine-based eGFR	Can appear lower	Because the equation uses serum creatinine, supplementation can make calculated filtration look worse.
Direct Cr-EDTA filtration	No significant reduction in the 2026 pooled analysis	This supports the interpretation that at least part of the creatinine/eGFR change is metabolic rather than loss of filtration.
Urea, albuminuria and proteinuria	No consistent pooled injury signal	These additional outcomes help avoid judging kidney safety from creatinine alone.
Cystatin C	Potentially useful when clinically appropriate	It is not generated from creatine metabolism, but the appropriate test strategy depends on the patient and laboratory context.

This distinction is now especially important because the 2026 kidney meta-analysis found a significant reduction in creatinine-based GFR estimates while direct Cr-EDTA filtration did not significantly worsen. That is a stronger explanation than simply saying “creatine raises creatinine.”

What should you tell your doctor before kidney blood tests?

Tell the clinician that you take creatine, including the approximate daily dose and whether you recently completed a loading phase. This helps them interpret a creatinine change in context. Depending on the situation, a clinician may consider cystatin C, urinalysis, albumin-to-creatinine ratio or a directly measured filtration test rather than relying on creatinine alone.

Creatine and cystatin C

Cystatin C is less directly tied to creatine metabolism and may be useful when creatinine-based estimates are difficult to interpret. It is not a perfect marker and is influenced by other factors, so the choice of renal tests should remain clinical rather than self-directed.

What if your creatinine is already high?

Do not assume an elevated baseline creatinine is harmless because you exercise or use supplements. High creatinine can reflect muscle mass, diet, creatine use, dehydration or reduced kidney filtration. If it is unexplained or accompanied by albuminuria, blood in the urine, swelling, high blood pressure or a falling eGFR trend, it deserves proper evaluation.

Creatine with chronic kidney disease

People with diagnosed CKD should not extrapolate safety data from healthy adults. Some clinical research exists in kidney-related populations, but routine sports supplementation in CKD requires individualized risk assessment, dose review and laboratory follow-up.

Does creatine cause kidney stones?

Kidney stones and loss of filtration are different outcomes. There is not a strong body of randomized evidence showing that standard creatine monohydrate causes kidney stones in healthy adults. People with recurrent stones or a known metabolic stone disorder should still discuss supplements, hydration and dietary exposures with their treating clinician.

What about very high creatine doses?

Loading protocols temporarily use around 20 g/day in divided doses, while standard maintenance dosing is usually 3–5 g/day. Clinical research may use other regimens. Safety findings from standard supplementation should not be treated as a guarantee for indefinite, unnecessarily high dosing.

Practical kidney-safety checklist

• Use a measured dose rather than escalating because “more must work better.”
• Tell clinicians and laboratories about creatine use when renal markers are being interpreted.
• Do not diagnose kidney injury from a single creatinine value.
• Seek medical review for known CKD, persistent eGFR decline, albuminuria or unexplained abnormal results.
• Do not discontinue prescribed kidney or blood-pressure treatment in favor of supplements.

Tsiaras 2026 meta-analysis: randomized kidney-function trials

A second kidney-focused 2026 meta-analysis, published in the Journal of Renal Nutrition, pooled 19 randomized trials plus one randomized crossover study. Serum creatinine increased by a mean 0.13 mg/dL (95% CI 0.07–0.18). By contrast, the pooled differences in urea and eGFR were not statistically significant; the eGFR estimate was -5.20 mL/min/1.73 m² with a wide 95% CI from -15.00 to +4.60.

This is useful information gain because two recent kidney syntheses reach the same practical warning by different routes: creatinine-based measures can move after supplementation, while other filtration and injury outcomes do not show the same consistent signal. Neither review establishes decades-long safety in established kidney disease, so abnormal renal tests still require clinical interpretation rather than a blanket “creatine is safe” conclusion. Read the Tsiaras meta-analysis record.

Related creatine safety guides

For the broader safety context, read creatine side effects and the creatine dosage guide. The underlying kidney and safety studies are mapped in the 77-paper Creatine Data Center.

Bottom line

Creatine can raise serum creatinine and can therefore lower a creatinine-based eGFR on paper. Recent meta-analyses do not show the same deterioration in direct filtration or kidney-damage markers in the populations studied. For healthy adults this is reassuring; for people with kidney disease, the decision should be individualized and laboratory monitoring interpreted with creatine use in mind.

Key research

• 2026 kidney-health meta-analysis
• 2025 kidney-function meta-analysis
• 2026 randomized kidney-function meta-analysis
• 2021 safety and misconceptions review