Is Creatine Bad for Your Kidneys? What the Research Shows

Is creatine bad for your kidneys? It is one of the most common worries about the most researched supplement in sports nutrition, and it usually starts the same way: someone gets routine blood work, sees a creatinine number flagged as high, and wonders if their daily scoop is to blame. The answer for healthy people is reassuring, but the reason behind that lab flag is worth understanding before you panic or quit.

Here is what controlled trials and the latest meta-analysis show about creatine and kidney function, why creatine can raise a lab marker without harming your kidneys, and who should talk to a doctor first.

Is Creatine Bad for Your Kidneys? Why People Worry

The concern has two roots. First, a few case reports in the late 1990s described kidney problems in people taking creatine. Those reports got wide media coverage, even though case reports cannot show cause and effect.

Second, and more important today, is a naming problem. Creatine and creatinine sound almost identical, and creatinine is one of the main numbers doctors use to judge kidney health. When creatine users see a high creatinine result, it is easy to connect the dots in the wrong direction.

Creatine vs Creatinine: The Lab Test Problem

Your muscles store creatine and use it to recycle energy during hard efforts. Every day, a small portion of that creatine breaks down into creatinine, a waste product your kidneys filter out. Because creatinine is produced at a fairly steady rate, labs use your blood creatinine, along with age and sex, to calculate an estimated glomerular filtration rate (eGFR). That estimate is a stand-in for how well your kidneys are filtering.

Here is the catch. Supplementing creatine increases the amount stored in muscle, which can increase how much creatinine is produced. Blood creatinine may tick up, and the calculated eGFR may drift down, even though actual filtration has not changed. Muscular people can show the same pattern simply because they carry more muscle.

A 2025 systematic review and meta-analysis in BMC Nephrology found a pattern consistent with this. Across the 12 studies in its creatinine analysis (21 in the full review), creatine was linked to a small but statistically significant rise in serum creatinine, significant in studies of a week or less and in those longer than 12 weeks but not in studies of 1 to 12 weeks, with no significant change in glomerular filtration rate. The authors described the creatinine rise as modest and transient, likely reflecting metabolic turnover rather than kidney impairment, and advised interpreting high creatinine in supplement users with caution.

What the Research Shows About Creatine and Kidney Function

The high-protein lifter study

One of the most useful trials, by Lugaresi and colleagues in 2013, tested the scenario people worry about most: lifters already eating a lot of protein who add creatine on top. Resistance-trained young men eating at least 1.2 g of protein per kg per day (intakes ranged up to 3.1 g/kg) were randomized to creatine or a dextrose placebo for 12 weeks. The creatine group loaded with 20 g per day for 5 days, then took 5 g per day.

Instead of relying on creatinine estimates, the researchers measured filtration directly with ⁵¹Cr-EDTA clearance, a gold-standard method. Twenty-six participants were included in the final analysis. Filtration rate did not differ between groups (roughly 101 to 109 mL/min/1.73 m² with creatine versus 103 to 107 with placebo), and creatinine clearance, urea, electrolytes and urine protein were essentially unchanged. The study was publicly funded by Brazilian research agencies, and the authors reported no conflicts of interest.

The limits matter too. It was a small, 12-week study in healthy young men. The authors noted their results may not apply to people who have, or are at risk of, kidney problems.

The bigger picture

That result fits the wider literature. A 2021 review in the Journal of the International Society of Sports Nutrition, written to address 12 common questions about creatine including kidney safety, concluded that creatine is relatively well tolerated, especially at recommended doses of 3–5 g per day or about 0.1 g per kg of body weight.

Who Should Be Careful

"Safe for healthy people" is not the same as "safe for everyone." Talk to your healthcare provider before using creatine if any of these apply:

• You have kidney disease or have been told your kidney function is reduced.
• You take medications that affect the kidneys, such as regular high-dose NSAID pain relievers, or medications your doctor monitors with kidney labs.
• You are pregnant or nursing, since research in these groups is limited.
• You have upcoming blood work. Tell your doctor you take creatine so a higher creatinine reading is interpreted in context. Your doctor may choose a test that is less affected by muscle, such as cystatin C.

How to Take Creatine Sensibly

For most people, 3–5 g of creatine monohydrate per day is all you need. Loading is optional; our creatine dosage guide covers when it makes sense. Drink normally, stick to the dose on the label, and skip the "more is better" mindset.

Form matters less than people think. Creatine monohydrate is the most studied form by far, which is why we use it. See creatine HCl vs monohydrate for a full comparison.

At CleanForm, we focus on quality. Pürest Creatine™ is micronized creatine monohydrate with nothing added. According to CleanForm, it is made with solvent-free processing and contains lower levels of manufacturing byproducts such as DCD, DHT, creatinine and cyanide than competitors' creatine. Every lot is screened for heavy metals including lead, arsenic, cadmium and mercury, and Certificates of Analysis are available for each batch.

Creatine and Kidneys FAQ

Does creatine raise creatinine levels?

It can. Creatine breaks down into creatinine, so supplementing may modestly raise blood creatinine. The 2025 meta-analysis found this rise without a significant change in filtration rate.

Should I stop creatine before a blood test?

Ask your doctor. Some people pause creatine for a short time before kidney labs, while others simply let their doctor know they take it. Either way, make sure whoever reads your results knows.

Is it safe to take creatine every day long term?

For healthy adults at standard doses, research has not shown harm to kidney function. Most kidney-specific trials run weeks to months, so if you plan to use it for years, routine checkups with your doctor are a sensible habit.

Is creatine safe with a high-protein diet?

In the Lugaresi trial, lifters eating 1.2 to 3.1 g of protein per kg per day showed no difference from placebo in directly measured kidney function after 12 weeks.

The Bottom Line

For healthy people, the evidence does not support the idea that creatine is bad for your kidneys. Creatine can nudge up blood creatinine, which can make a standard kidney estimate look worse than it is, but a trial that measured filtration directly found no harm, and a 2025 meta-analysis found no significant change in filtration rate. Take 3–5 g per day, choose a clean, tested monohydrate, tell your doctor you use it before blood work, and get medical advice first if you have a kidney condition.

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Sources: 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;10:26. Kabiri Naeini E, et al. Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. BMC Nephrol. 2025;26. Antonio J, et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr. 2021;18:13.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement.