In people with healthy kidneys the research does not point to damage from creatine at usual doses. What creatine does do is raise the creatinine in your blood, and that is a different substance. The confusion between creatine and creatinine is the entire reason this rumour has run for thirty years.
Two words separated by a couple of letters. Half a century of supplement panic.
What is the difference between creatine and creatinine?
Creatine is the substance you take and your muscles use to deliver energy quickly. Creatinine is the waste product formed when creatine breaks down spontaneously. Your kidneys filter that waste product out, and labs use the amount in your blood as a measure of kidney function.
Take creatine and there is more creatine in your system. So more of it breaks down into creatinine.
Your kidney filters just as well but is handed more. The number on your result goes up. Your kidney function does not go down.
What else creatine does to your blood values sits in creatine and your blood values.
What does the research say about creatine and kidney damage?
Controlled studies in people with healthy kidneys show no deterioration in kidney function at usual doses. A 2023 narrative review in Nutrients examined the concern directly and concluded that the rise in creatinine does not necessarily indicate kidney dysfunction, because creatine converts spontaneously into creatinine (PMID 36986197).
The title of that paper says plenty. The authors asked whether it is time for a requiem for the idea of creatine-induced kidney failure.
The nuance that remains: in people with existing kidney disease, less is known about long term use. If you have a known kidney condition, discuss creatine with your doctor before starting.
How much will my creatinine rise on creatine?
In practice you usually see a modest rise that stays within or just above the reference range. How much exactly varies by person and tracks your dose, your muscle mass and how long you have been taking it. A loading phase of 20 grams a day produces a larger jump than a maintenance dose.
The point is not the exact percentage. The point is that the rise is an expected consequence of the conversion, not of a kidney failing to keep up.
Inconveniently, this effect stacks on top of the muscle mass effect. A muscular lifter who also supplements creatine has two independent reasons for a higher creatinine, and neither of them is kidney damage.
Picture a 100 kilo lifter taking 5 grams of creatine a day who gets a creatinine of 115 back. Two innocent explanations are already on the table before you need to think about his kidneys at all.
How do you prove it is the creatine and not your kidneys?
There are two routes and both are simple. Measure cystatin C alongside, because that protein is not influenced by creatine or muscle mass. Or stop creatine for three to four weeks and measure again. If your eGFR stays at the low number, the supplement was not the reason.
| Situation | What you see | What it probably means | Next step |
|---|---|---|---|
| Creatinine high, cystatin C normal | Large gap between the two eGFR results | Muscle mass and creatine explain the number | Repeat in 6 to 12 months |
| Creatinine high, cystatin C also high | Both eGFR results low | This is probably not about your supplement | Book an appointment with your GP |
| Creatinine high after a 4 week wash-out | Value holds steady | Creatine was not the explanation | Have urine checked for protein and discuss it |
| Creatinine falls after wash-out | Value drops back toward your old level | The supplement was raising the number | Restart freely, mention it at your next draw |
That second row is the only one that counts. Every other row is reassurance, that one is a reason to look further.
Why cystatin C works so much better here is covered in cystatin C in muscular athletes.
So what should you watch with creatine?
Drink enough, because creatine pulls water into your muscle cells and your fluid needs rise slightly. Do not combine significant dehydration with prolonged use of anti-inflammatories. And mention your creatine use when you have blood drawn, because otherwise the reviewer reads your result without that context.
That last piece of advice is the one most often forgotten. A doctor who knows you take creatine reads a creatinine of 110 very differently.
The 360 Health test runs cystatin C as standard, so you get the check without having to ask. The full overview of your kidney values sits in kidney values in athletes.
My own position: creatine is one of the best researched supplements available, and the kidney panic around it is largely a measurement artefact. Check it rather than quitting on the strength of a rumour.
References
- de Souza e Silva A, et al. Is It Time for a Requiem for Creatine Supplementation-Induced Kidney Failure? A Narrative Review. Nutrients. 2023. PMID 36986197.
- Difference between kidney function by cystatin C versus creatinine and association with muscle mass and frailty. J Am Geriatr Soc. 2024. PMID 38819605.
- Nierstichting. Blood testing for creatinine and kidney function. Accessed 2026.
Disclaimer
Every blood test result includes a professional assessment from a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. A blood test is a tool to walk into the conversation with your GP better informed, not a diagnosis in itself. Discuss any abnormal value with your GP.
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