Is creatine bad for your kidneys? What the research shows

For healthy adults taking normal doses, creatine has not been shown to damage the kidneys. Controlled studies that measure kidney function directly find no harm, even though creatine can raise creatinine, a blood marker that is often read as a sign of kidney trouble. The evidence is much thinner for people who already have kidney disease, so that group should decide with a doctor.

By Creatine Today · Editorial policy

Does creatine damage your kidneys?

Not in healthy people at normal doses, based on the research we have. The International Society of Sports Nutrition reviewed the evidence in 2017 and concluded that creatine is safe and well tolerated in healthy people, with studies using up to 30 g a day for up to 5 years. In one study it cites, college football players took creatine for 21 months and showed no meaningful differences from non-users in markers of kidney function.

A 2023 review asked directly whether it is time to retire the idea of creatine-induced kidney failure. Its authors found that a few case reports and animal studies raised concerns, but controlled human trials did not support them. A 2025 meta-analysis of 21 studies came to a similar conclusion: creatine slightly raised serum creatinine, but GFR did not change significantly.

The everyday dose matters. The research behind these conclusions mostly used 3–5 g a day, sometimes after a short loading phase of about 20 g a day. Taking more than that does not add benefit for most people.

Why does creatine look like a kidney problem on blood tests?

Creatine and creatinine are different molecules, but they are closely linked. Your muscles slowly turn a small part of their creatine into creatinine every day. Your kidneys then filter that creatinine out of the blood.

Doctors use blood creatinine to estimate how well the kidneys filter, a number called eGFR. When you take creatine, your body has more creatine to break down, so creatinine can rise even if your kidneys are working normally. The lab result can then look like reduced kidney function. This is the main reason the kidney myth started.

We explain this in detail, including what to tell your doctor and which other tests can help, in our guide to creatine, creatinine, and blood tests.

Can creatine cause kidney stones?

There is no good evidence that it does, but there is also very little research on the question. We could not find a controlled trial that measured kidney stones as an outcome in people taking creatine. The large safety reviews do not list kidney stones as a known effect.

If you have had kidney stones before, the safest approach is to follow the fluid and diet advice your doctor has given you and to mention creatine at your next visit. Do not assume that creatine will cause stones, and do not assume it is proven safe for you either.

Should you take creatine with kidney disease?

This is a question for your doctor, not for a general guide. Most creatine research has been done in people with healthy kidneys. The 2023 review noted that more studies in people with existing kidney disease are still needed. If you have chronic kidney disease, are on dialysis, have had a kidney transplant, or take medicines that affect the kidneys, talk to your nephrologist or primary care clinician before you start.

The same applies if you take pain relievers such as ibuprofen every day, because those medicines can also affect the kidneys. Our side effects guide covers this in more detail.

Can you take creatine with one kidney?

The only direct evidence is a single case. In 2010, researchers followed a 20-year-old man with one kidney and mildly reduced kidney function. He took 20 g a day for 5 days and then 5 g a day for 30 days. His kidney function, measured with an accurate lab method, did not change. His serum creatinine went up slightly, which on its own would have suggested a problem that was not there.

One person is not enough to say creatine is safe for everyone with a single kidney. If you have one kidney, ask your doctor. If you both decide to try it, a baseline blood test and a follow-up test, with your doctor aware that you take creatine, is a reasonable plan.

Are there any reports of kidney injury?

Yes, a few, and they are worth knowing about. In 2025, doctors described a 17-year-old who developed acute kidney injury after a 6-day high-dose creatine loading regimen. A case report cannot prove that creatine caused the problem, and it does not change what controlled trials show in healthy adults. It does support two practical points: avoid very high doses, and be more careful with creatine in teenagers.

See a doctor if you notice pain in your side or lower back, much less urine than usual, dark or bloody urine, or swelling in your legs, whether or not you take creatine. Do not try to explain these symptoms away as a supplement effect.