Is Creatine Bad for Your Kidneys? Creatinine, Lab Tests and the Research

For healthy adults taking normal doses, creatine is not bad for your kidneys. Randomized trials that measured kidney filtration directly, in healthy lifters on high-protein diets and in adults with type 2 diabetes, found no difference between creatine and placebo. What creatine can do is nudge up creatinine, the blood marker most routine kidney tests are built on. So a lab result can look off while your kidneys are fine. If you already have kidney disease or reduced kidney function, make creatine a conversation with your clinician first.

The whole scare runs on one extra syllable. Creatine is the supplement. Creatinine is the waste product your kidneys clear. Mix them up, and a harmless bump on a lab report starts to look like organ damage.

Is creatine bad for your kidneys?

Not in healthy people taking recommended doses. A 2021 evidence review in the Journal of the International Society of Sports Nutrition describes more than 20 years of research showing no adverse effects of recommended creatine doses on kidney health in healthy individuals. The International Society of Sports Nutrition (ISSN) position stand likewise found no compelling evidence that creatine harms kidney function in healthy people.

The strongest evidence comes from studies that skipped the guesswork. Instead of estimating kidney function from creatinine, they measured filtration directly with a radioactive tracer (⁵¹Cr-EDTA clearance). A 12-week randomized trial in resistance-trained men eating a high-protein diet and a 12-week randomized trial in adults with type 2 diabetes both found no difference in measured filtration between creatine and placebo. A 2025 meta-analysis of 21 studies reached the same overall picture: a small rise in blood creatinine and no significant change in filtration rate.

If your kidneys already have a problem, that research does not answer your question. Your clinician should (more on that below).

Creatine vs creatinine: why blood tests can look off

Creatine is a compound your body makes and stores in muscle, where it helps recycle quick energy for hard efforts. (For the full rundown, see what creatine monohydrate does.) According to the NIH Office of Dietary Supplements (ODS), your liver and kidneys make about 1 g of creatine a day, and foods such as beef supply roughly 2 g per pound. Used creatine becomes creatinine, which your kidneys filter out. Step by step:

1. Creatine is stored in muscle as creatine and phosphocreatine, whether it came from your own production, meat or a scoop.
2. Some of it breaks down into creatinine on its own, without an enzyme, as the 2021 review explains.
3. Creatinine moves into the blood, and healthy kidneys filter it into urine.
4. Blood creatinine also tracks muscle mass and diet. More muscle, more meat or a creatine supplement can all push the number up.

Routine kidney checks usually report an estimated glomerular filtration rate (eGFR), and blood creatinine is the most widely used marker behind it. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) notes that creatinine is affected by muscle mass and that creatinine-based estimates may be unreliable with extremes of body size, muscle mass or diet. It names bodybuilders and people on vegetarian or low-meat diets. The 2025 meta-analysis authors put it bluntly: estimating kidney function from creatinine alone in creatine users "can be deceptive."

Why did my creatinine go up?

The usual suspects are the creatine itself, more muscle, or more meat. A genuine kidney problem is also on the list, and only your clinician can rule it in or out. When creatinine alone may mislead, NIDDK lists alternatives: a cystatin C blood test, which is generally less swayed than creatinine by factors other than kidney function (although steroid use, thyroid problems, body fat and inflammation can shift it), or a measured clearance or measured GFR test. Measured GFR is labor-intensive and rarely done outside research, so your clinician will pick the test that fits.

What do studies that measured kidney function find?

When researchers measured filtration directly, creatine did not move it.

Creatine and kidney function: trials with measured filtration, plus the 2025 meta-analysis

Study	Who was studied	Protocol	Kidney result
Lugaresi et al., 2013 (randomized, double-blind)	26 resistance-trained men eating at least 1.2 g protein per kg daily (12 creatine, 14 placebo analyzed)	20 g/day for 5 days, then 5 g/day; 12 weeks	Measured GFR rose from 101.4 to 108.8 with creatine vs 103.3 to 106.7 mL/min/1.73 m² with placebo (p = 0.64). Creatinine clearance, urea, electrolytes and urine protein and albumin were essentially unchanged.
Gualano et al., 2011 (randomized, double-blind)	25 men and women over 45 with type 2 diabetes in an exercise training program (13 creatine, 12 placebo, per the 2025 meta-analysis's study table)	5 g/day creatine monohydrate or placebo; 12 weeks	Measured GFR went from 90.4 to 96.1 with creatine vs 97.9 to 96.4 mL/min/1.73 m² with placebo (p = 0.58). Creatinine clearance, urea, electrolytes, proteinuria and albuminuria were unchanged.
Naeini et al., 2025 (systematic review and meta-analysis)	21 studies; 12 pooled for creatinine (177 creatine vs 263 control), 5 pooled for GFR (69 vs 74)	Creatine protocols in human studies published 2000 to March 2025	Small, statistically significant rise in serum creatinine; no significant difference in GFR, whether estimated or directly measured.

The Lugaresi trial is a useful stress test: it combined daily creatine with a high-protein diet (1.2 to 3.1 g per kg), two things people blame on the kidneys, and filtration still matched placebo. The researchers chose the tracer method because creatine's conversion to creatinine can falsely suggest reduced kidney function when only creatinine is checked.

The diabetes trial extends the picture beyond healthy lifters, and it confirmed the creatine reached muscle: phosphocreatine rose from 44 to 70 mmol/kg with creatine and slipped from 52 to 46 with placebo. Filtration held steady anyway. The 2025 meta-analysis authors read the small creatinine rise as metabolic turnover rather than kidney impairment, and concluded the GFR results suggest preserved kidney function.

Where did the kidney worry come from?

Two things, according to the 2021 review: confusion between creatine and creatinine, and a 1998 case report in The Lancet. In it, Pritchard and Kalra described a young man who had lived with a kidney disease (focal segmental glomerulosclerosis with relapsing nephrotic syndrome) for 8 years and had taken the immunosuppressant cyclosporine for 5 years. After he took creatine, 15 g a day for a week and then 2 g a day for 7 weeks, his blood creatinine rose, a clearance figure calculated from it suggested his kidneys were declining, and he was encouraged to stop.

The review points out what that report left out. It was already known that creatine intake raises blood creatinine, and the maintenance dose was only slightly more creatine than a typical meat eater gets from food: roughly a large steak's worth, with meat supplying about 0.7 g per 6-ounce serving. The same review notes that when researchers reviewed a small number of later case reports linking creatine to kidney problems, those cases were confounded by medications, pre-existing kidney disease, other supplements, inappropriate doses (in one example, around 100 times the recommended amount) or anabolic steroid use. Rare reports do describe kidney injury in people with no known kidney disease, such as a previously healthy 18-year-old who developed biopsy-confirmed acute kidney injury while taking creatine and recovered fully within 25 days of stopping. New vomiting, swelling or much less urine than usual needs prompt medical care, whatever the cause.

A case report describes one person and everything else going on in their life. A randomized trial compares groups that differ only by the supplement, which is why the trials above carry the weight.

Who should talk to a doctor before taking creatine?

The reassuring research covers healthy adults and, in one trial, adults with type 2 diabetes. Check with your clinician before starting creatine if any of these apply:

• Kidney disease or reduced kidney function, including a past abnormal kidney test
• A single kidney
• Diabetes that has affected your kidneys
• Medicines that affect the kidneys or need kidney monitoring
• Pregnancy or breastfeeding
• Being under 18

Expert sources give the same advice for kidney disease. The ISSN position stand notes the suggestion that people with pre-existing kidney disease consult their physician before supplementing, and Mayo Clinic says research on creatine in people with kidney disease is limited. Bring your product label and dose to that conversation; "some powder, most days" is hard for anyone to assess.

How much creatine is safe for your kidneys?

The studied daily dose is 3–5 g. ODS describes two common adult protocols: an optional loading phase of 20 g a day, split into four 5 g servings for 5–7 days, followed by 3–5 g a day, or simply 3–6 g a day from the start. The healthy-lifter kidney trial used the first pattern. Weighing whether to load at all? Our guide to the creatine loading phase walks through the tradeoffs.

At the high end, the ISSN position stand reports intakes of up to 30 g a day for up to 5 years as safe and well tolerated in healthy people and several patient groups. Treat that as the edge of what has been studied, not a target. For context, at ODS's figure of about 2 g per pound, a 5 g scoop holds roughly the creatine in two and a half pounds of beef.

On duration, ODS cites evidence that several years of use is safe, while the 2025 meta-analysis notes that kidney-specific data beyond a year are still sparse. For long-term daily use, the 3–5 g maintenance dose keeps you inside the best-studied range.

Quick answers

What organ is creatine hard on?

The kidneys get the blame because they clear creatinine, but controlled trials in healthy adults at recommended doses have not shown kidney harm. The effects people notice are more ordinary: a 1–2 kg weight gain within a month in some strength-training studies (ODS), early water retention, which the 2021 review calls the most common side effect, and reported nausea or diarrhea.

Is creatine safe to take daily?

For healthy adults, yes. A daily 3–5 g is how the studies dosed it, and ODS considers creatine safe for healthy adults, with evidence supporting several years of use. Our guide to whether creatine is safe covers the full side-effect picture, and you can keep the same scoop going on rest days too.

Should you mention creatine before a blood test?

Yes. Tell your clinician you take creatine and how much, so they can read your creatinine in context and decide whether a cystatin C test or a measured clearance would help (NIDDK). Do not stop and restart creatine on your own to change a result; let your clinician decide what the numbers need.

Using Infinite Labs Creatine Monohydrate

If creatine fits your plan, keep it simple: creatine monohydrate is the most widely used and studied form, according to ODS, and it is the form the healthy-lifter kidney trial used. Infinite Labs Creatine Monohydrate is a strong pick for exactly that routine:

• 5 g per scoop, the same daily maintenance dose used after loading in the kidney trial, and within the 3–5 g range studied.
• 60 servings, or about two months at one scoop a day.
• Unflavored powder, so it fits whatever you already drink. Follow the mixing directions on the container.
• Allergen note: the label states that this product contains wheat, so skip it if you need to avoid wheat.

Certificates of analysis are available on request. If you are in the check-with-your-clinician group above, bring the label along to that appointment.

The takeaway

For healthy kidneys at normal doses, the research is reassuring: trials that measured filtration directly found no harm, and a small creatinine rise likely reflects creatine turnover, not kidney damage. If you have kidney disease, reduced kidney function or another item on the list above, talk to your clinician before you start. Either way, tell whoever orders your blood work that you take creatine, so your numbers are read in context.

Sources

• Naeini EK et al. Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. BMC Nephrology, 2025.
• Lugaresi R et al. Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet? J Int Soc Sports Nutr, 2013.
• Gualano B et al. Creatine supplementation does not impair kidney function in type 2 diabetic patients. Eur J Appl Physiol, 2011.
• Pritchard NR, Kalra PA. Renal dysfunction accompanying oral creatine supplements. The Lancet, 1998.
• Taner B et al. The effects of the recommended dose of creatine monohydrate on kidney function. NDT Plus, 2011.
• Antonio J et al. Common questions and misconceptions about creatine supplementation. J Int Soc Sports Nutr, 2021.
• Kreider RB et al. ISSN position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr, 2017.
• NIDDK: Clinical Measurements and eGFR Accuracy.
• NIH Office of Dietary Supplements: Dietary Supplements for Exercise and Athletic Performance.
• Mayo Clinic: Creatine.

This article is educational and is not medical advice. Infinite Labs Creatine Monohydrate is not intended to diagnose, treat, cure, or prevent any disease.