Does Creatine Damage Your Kidneys? What the Research Shows

No, creatine does not damage the kidneys in healthy people. A 2025 systematic review and meta-analysis of 21 studies found creatine supplementation causes a small, statistically significant rise in a blood marker called creatinine, but no significant change in glomerular filtration rate (GFR), which is the actual measure of how well your kidneys are filtering.

If you've seen warnings online that creatine is "hard on your kidneys," here's where that confusion comes from and what the research measuring real kidney function, not just a lab number, has actually found.

Does creatine damage your kidneys?

Not based on the evidence in healthy people. A 2025 systematic review and meta-analysis by Naeini and colleagues, published in BMC Nephrology, pooled 21 studies on creatine supplementation and kidney health. Twelve of those studies, covering 440 participants, were eligible for a meta-analysis of serum creatinine specifically. The result was a small but statistically significant increase in serum creatinine (a mean difference of 0.07 µmol/L), while GFR itself showed no significant change across the pooled studies. In plain terms, one marker nudged up slightly while the thing that marker is supposed to estimate, actual kidney filtration, didn't move.

Why does creatine raise your creatinine levels, then?

Because of how creatinine is made, not because of kidney strain. Creatine and phosphocreatine stored in muscle break down at a fairly steady, ongoing rate into creatinine, which the kidneys then filter out of the blood. Taking creatine supplements increases the total creatine pool in your muscles, which means slightly more creatinine gets produced as a byproduct and shows up on a blood test.

Standard blood panels and the eGFR formulas doctors use both treat creatinine as a stand-in for kidney function, built on the assumption that it comes from ordinary muscle turnover. Supplementing with creatine breaks that assumption a little, which is exactly why a lifter's blood work can show a higher creatinine number without any actual drop in kidney performance. It's a measurement quirk, not a red flag, though it's also why a doctor unfamiliar with sports supplements might misread it.

What does long-term research say?

The same thing the 2025 meta-analysis found, just from decades earlier. A review by Poortmans and Francaux, published in 1999 in Medicine & Science in Sports & Exercise, looked at athletes who had been using creatine long-term, including some for up to five years, and found no impairment in measured kidney function. That's two separate bodies of evidence, over 25 years apart, using different methods, landing on the same answer for healthy people.

Is creatine safe if you have kidney disease or other risk factors?

That's genuinely less clear, and it's worth being honest about. Most of the studies behind the "creatine doesn't harm healthy kidneys" conclusion excluded people who already had chronic kidney disease, diabetes affecting kidney function, or similar conditions. The research not finding harm in healthy people doesn't automatically extend to someone whose kidneys are already compromised. If that's your situation, or you take medications that affect kidney function, check with a doctor before adding creatine rather than assuming the general population research applies.

Does pairing creatine with a high-protein diet add extra risk?

Not according to the evidence available in people with healthy kidneys. High protein intake on its own hasn't been shown to damage healthy kidneys either, and there's no research suggesting the combination of creatine and a high-protein diet creates a compounding risk in people without existing kidney issues. The same caveat carries over, though: the "no risk" conclusion is specific to healthy kidneys, and anyone with kidney risk factors should treat both decisions as something to run by a doctor.

Worrying about a supplement's safety is a reasonable instinct, but once that's settled, the more useful question becomes whether it's actually earning its place in your routine. Creatine's real benefit shows up as better performance in your training, an extra rep or a bit more weight, not as something you can feel directly. Ori tracks every set, rep, and weight you log, so you can see whether creatine is actually moving your numbers instead of guessing from how a session felt.

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FAQ

Does creatine damage your kidneys? The research in healthy people says no. A 2025 systematic review and meta-analysis of 21 studies found creatine supplementation produced a small, statistically significant rise in serum creatinine but no significant change in glomerular filtration rate (GFR), the actual measure of how well kidneys are filtering.

Why does creatine raise your creatinine levels on a blood test? Creatine and phosphocreatine break down into creatinine at a steady rate inside muscle tissue, and that creatinine gets filtered out by the kidneys. Taking creatine supplements adds to that pool, which nudges the number up on a standard blood test, even though it reflects a bigger creatine pool, not kidney injury.

What does long-term research say about creatine and kidney function? A review by Poortmans and Francaux, published in 1999 in Medicine & Science in Sports & Exercise, looked at athletes using creatine long-term, in some cases up to five years, and found no impairment in actual kidney function. A 2025 meta-analysis reached the same conclusion using direct GFR measures, over two decades later.

Is creatine safe if you already have kidney disease? That's not something the existing research can answer confidently, since most of these studies excluded people with pre-existing kidney disease, diabetes affecting the kidneys, or similar risk factors. If any of that applies to you, talk to a doctor before starting creatine rather than assuming the healthy-population research covers your situation.

Does combining creatine with a high protein diet add extra risk to your kidneys? There's no research showing that combination causes harm in people with healthy kidneys. Both creatine and high protein intake have been studied individually without turning up kidney damage in healthy people, but the same caveat applies: if you have existing kidney risk factors, that's a conversation for a doctor, not a guess based on general population research.