This is Part 3 in my series on creatine supplements. Today’s post focuses on the relationship between creatine supplements and kidney health.
For background information, see:
? Part 1: Creatine Supplements – The Basics of What Clinicians Need to Know
? Part 2: Creatine Supplements in Special Populations
These systematic reviews published in 2025 form the basis for this discussion:
- Matczak M, et al. The impact of creatine supplementation on the development of kidney disease – literature review. Quality in Sport. 2025;38:57864.
- Villa A, Trotta L, Faraci G. The impact of creatine supplementation on renal function: A case report and literature review. 2025.
Why Might Creatine Supplements Impact Kidney Health?
The breakdown product of creatine supplements is creatinine. This means that people taking creatine supplements will have higher levels of creatinine in their blood.
Because creatinine is used to estimate glomerular filtration rate (eGFR), higher levels of creatinine will result in a lower eGFR value.
But does this mean that creatine supplementation harms the kidneys?
According to the case report by Villa et al. (2025), most case reports of healthy adults presenting with low eGFR while using creatine supplements show recovery of kidney function once supplementation is stopped. This suggests that while eGFR may appear lower, it reflects increased circulating creatinine rather than actual kidney damage.
Have All Case Reports Concluded That Creatine Doesn’t Harm the Kidneys?
No. Both Villa et al. and Matczak et al. reference a case involving a 20-year-old healthy individual who developed creatine-induced interstitial nephritis after prolonged, high-dose creatine supplementation.
The authors of the original report hypothesized that this could have been due to impurities in the supplement or metabolites of creatine triggering immune-mediated kidney inflammation.
Additionally, there are several case reports of individuals experiencing kidney injury after using creatine in combination with other substances, such as anabolic steroids. These are difficult to interpret given the multi-substance exposure.
What About Experimental Studies?
While case reports can raise important clinical questions, they represent lower levels of evidence. To evaluate kidney safety more reliably, it’s important to review findings from randomized controlled trials (RCTs).
In the review by Matczak et al., the authors summarized RCTs published between 1997 and 2020. Overall, creatine supplements were not associated with kidney function decline, in either short-term or long-term trials.
I took a closer look at three of the RCTs included in the Matczak review. Below are the references and main conclusions, highlighting that only Domingues et al. directly investigated kidney safety, while the others assessed kidney function as a secondary outcome.
1. Domingues et al., 2020
Study: Does creatine supplementation affect renal function in patients with peripheral artery disease? Ann Vasc Surg. 2020;63:45–52.
Dose: 20 g/day for 1 week, then 5 g/day for 7 weeks
Outcome: Serum creatinine, creatinine clearance
Conclusion:
“Eight weeks of creatine supplementation is safe and does not compromise the renal function of patients with peripheral arterial disease.”
Results Summary:
Creatinine clearance pre 108 ± 59 vs post 117 ± 52, p = 0.366.
2. Sales et al., 2020
Study: Creatine supplementation (3 g/day) and bone health in older women: A 2-year randomized, placebo-controlled trial. J Gerontol A Biol Sci Med Sci. 2020;75:931–938.
Dose: 3 g/day for 24 months
Outcome: Serum creatinine
Conclusion:
“Creatine supplementation for more than 2 years did not improve bone health in older postmenopausal women with osteopenia, nor did it affect lean mass or muscle function in this population.”
Results Summary:
Serum creatinine pre 0.71 (0.69–0.73) vs post 0.76 (0.72–0.79), p = 0.001, with a similar change in the placebo group (p = 0.435 for difference between groups).
3. Roschel et al., 2021
Study: Supplement-based nutritional strategies to tackle frailty: A multifactorial, double-blind, randomized placebo-controlled trial. Clin Nutr. 2021;40:4849–4858.
Dose: 6 g/day of creatine for 16 weeks
Outcome: Cr-EDTA clearance (gold-standard measure of kidney function)
Conclusion:
“Neither protein (whey and soy), leucine, nor creatine supplementation enhanced resistance training-induced adaptations in pre-frail and frail elderly.”
Results Summary:
Cr-EDTA clearance:
- Whey: pre 78.3 → post 75.65
- Whey + creatine: pre 79.34 → post 70.41
- Creatine only: pre 69.92 → post 74.79
- Placebo: pre 74.95 → post 72.51
Summary of Findings
Both Sales et al. and Roschel et al. included large cohorts (n = 200) and followed participants for extended periods (2 years and 4 months, respectively).
Both reported non-significant increases in creatinine over time, with no significant difference between creatine and placebo groups.
These studies used low-to-moderate doses (3–6 g/day) and showed no evidence of kidney harm. However, neither demonstrated meaningful improvement in bone or muscle outcomes, suggesting that while creatine may not be harmful, it may also not provide clear clinical benefit in these groups.
Key Limitations of Current Research (My Perspective)
- Most studies to date have been conducted in people without known kidney disease.
- We lack evidence on how creatine supplementation might impact people with CKD.
- Because early-stage kidney disease is often asymptomatic, individuals may have unrecognized CKD and unknowingly place themselves at risk.
- There is theoretical plausibility that if kidneys are already damaged, increasing solute load through creatine supplementation could accelerate decline.
- In the long-term frailty trial (Sales et al.), which included a population I would be most interested in supporting with supplementation, no benefit was found. Given potential risk and uncertain benefit, I would refrain from recommending creatine supplements in my patient population with or at risk for kidney disease.
Key Takeaways
- While creatine supplements have been well studied, with several high-quality, placebo-controlled, long-term trials showing safety in the general population.
- However, these same studies have not shown clear benefit on bone or muscle health among older adults or people with frailty.
- No studies have specifically evaluated safety in individuals with diagnosed kidney disease.
- For patients with reduced kidney function, caution is warranted until more evidence becomes available.
But what about populations who have already lost kidney function—those with end-stage kidney disease receiving renal replacement therapy?
? Keep reading: Part 4: Creatine Supplements in End-Stage Kidney Disease
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