Is creatine safe for your kidneys?

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Why is this a concern?

Considering creatine’s popularity as a sports supplement, it isn’t surprising that concerns have been raised about potential adverse effects — especially on the kidneys.

Why the kidneys?

To store the creatine you ingest, and the creatine your liver produces, your skeletal muscles,[1] your brain,[2] and other tissues transform it into phosphocreatine. And when they use their stores to recycle adenosine triphosphate (ATP), often called life’s energy currency, one of the byproducts is creatinine.

Your kidneys excrete this creatinine unchanged. If their function declines, so does creatinine clearance. Creatinine clearance can be estimated from a blood test or measured through a combination of blood test and 24-hour urine sample.

Creatinine blood levels are the most commonly used indicator of kidney function: it is assumed that if your levels are high, your kidneys haven’t done their job.

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Your skeletal muscles make for >90% of your creatine stores,[1] so the more muscle you have, and the more you use it, the more creatinine you produce.[3][4] Also, greater animal protein intake has been associated with greater muscle mass[5][6] and higher creatinine excretion.[7] And yes, supplemental creatine can increase your blood levels of creatinine beyond the normal ranges;[8][9] but can we really conclude your kidneys are being damaged?

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Concerns have been raised over creatine supplementation because it can increase creatinine levels beyond the normal range — a marker of kidney damage.

The evidence

For people with healthy kidneys

The evidence collected in our creatine Human Effect Matrix shows that creatine supplementation does not affect any measure of kidney health apart from creatinine levels. Moreover, scientific reviews on both the long- and short-term safety of supplemental creatine have consistently found no adverse effects on kidney function.[10][11][12][13][14][15][16][17]

Most healthy people can reap the performance benefits of creatine with just 3–5 g/day, but creatine nonresponders and people with high muscle mass may benefit from 10 g.[17] Doses >10 g/day have been found not to impair kidney function, but there are fewer long-term trials on such high doses.[17]

In healthy adults, doses ≤5 g/day are unlikely to increase creatinine levels significantly,[12][18][14] but higher doses might cause a false positive — an increase in creatinine that may be misinterpreted as a sign of kidney damage.[12][19][8] Most studies, however, have noted only a small increase in creatinine levels even with doses ≈20 g/day.[12][19][20]

Although taking creatine may increase creatinine levels, long- and short-term studies have found that creatine doses ≤10g/day don’t impair kidney health in people with healthy kidneys.

For people with kidney issues

In people whose kidneys don’t function optimally, supplemental creatine seems to be safe, too.

One case study found that a man’s single kidney suffered no harm from 20 g/day for 5 days followed by 5 g/day for 30 days.[21] An RCT in type 2 diabetics with various stages of kidney disease showed no significant decline in kidney function from 5 g/day for 12 weeks.[22] Two clinical trials saw no detriment in people with kidney disease.[23][24]

However, studies in people with suboptimal kidney function are fewer than in healthy people, and they are short-term. People with kidney dysfunction, or at risk for developing kidney dysfunction (e.g., people with diabetes, high blood pressure, or family history of kidney disease; people over sixty; and non-Hispanic blacks), might wish to forgo creatine, or otherwise take only the lowest effective dose (3 g/day)[17] after talking to their doctor.

Finally, let’s mention that, since creatine can increase water retention, it could theoretically harm people whose kidney disorder is being treated with diuretics, which cause water loss.[17]

Limited short-term evidence indicates that people with suboptimal kidney function may safely supplement with creatine. However, long-term studies are lacking.

Pro tip: test before supplementing

While creatine is unlikely to hurt your kidneys, its ability to raise creatinine levels may mask underlying issues. Consider having your creatinine levels tested before you start taking creatine, so as to get a baseline and check up on your kidney function. If you are already taking creatine yet plan to have your creatinine tested, cease supplementation 3 weeks prior to testing so as to prevent a false positive.

Bottom line

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Short- and long-term creatine supplementation does not appear to impair kidney function in people with healthy kidneys.

Limited short-term evidence has found creatine to be safe for people with suboptimal kidney function, but caution is warranted.

When caused by supplemental creatine, elevated creatinine levels are not indicative of kidney damage. Creatine’s ability to raise creatinine levels may mask underlying issues, however, so if you plan to check up on your kidney function by having your creatinine levels tested, stop taking creatine at least 3 weeks before the test.

References
2.^Braissant O, Henry H, Béard E, Uldry JCreatine deficiency syndromes and the importance of creatine synthesis in the brainAmino Acids.(2011 May)
3.^Samra M, Abcar ACFalse estimates of elevated creatininePerm J.(2012 Spring)
4.^Baxmann AC, Ahmed MS, Marques NC, Menon VB, Pereira AB, Kirsztajn GM, Heilberg IPInfluence of muscle mass and physical activity on serum and urinary creatinine and serum cystatin CClin J Am Soc Nephrol.(2008 Mar)
5.^Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SMA systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adultsBr J Sports Med.(2018 Mar)
7.^Alexandrov NV, Eelderink C, Singh-Povel CM, Navis GJ, Bakker SJL, Corpeleijn EDietary Protein Sources and Muscle Mass over the Life Course: The Lifelines Cohort StudyNutrients.(2018 Oct 10)
9.^McCall W, Persky AMPharmacokinetics of creatineSubcell Biochem.(2007)
10.^Poortmans JR, Francaux MAdverse effects of creatine supplementation: fact or fiction?Sports Med.(2000 Sep)
11.^Farquhar WB, Zambraski EJEffects of creatine use on the athlete's kidneyCurr Sports Med Rep.(2002 Apr)
12.^Pline KA, Smith CLThe effect of creatine intake on renal functionAnn Pharmacother.(2005 Jun)
13.^Francaux M, Poortmans JRSide effects of creatine supplementation in athletesInt J Sports Physiol Perform.(2006 Dec)
14.^Persky AM, Rawson ESSafety of creatine supplementationSubcell Biochem.(2007)
15.^Kim HJ, Kim CK, Carpentier A, Poortmans JRStudies on the safety of creatine supplementationAmino Acids.(2011 May)
16.^Gualano B, Roschel H, Lancha AH Jr, Brightbill CE, Rawson ESIn sickness and in health: the widespread application of creatine supplementationAmino Acids.(2012 Aug)
17.^Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HLInternational Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicineJ Int Soc Sports Nutr.(2017 Jun 13)
18.^Ropero-Miller JD, Paget-Wilkes H, Doering PL, Goldberger BAEffect of oral creatine supplementation on random urine creatinine, pH, and specific gravity measurementsClin Chem.(2000 Feb)
21.^Gualano B, Ferreira DC, Sapienza MT, Seguro AC, Lancha AH JrEffect of short-term high-dose creatine supplementation on measured GFR in a young man with a single kidneyAm J Kidney Dis.(2010 Mar)
22.^Gualano B, de Salles Painelli V, Roschel H, Lugaresi R, Dorea E, Artioli GG, Lima FR, da Silva ME, Cunha MR, Seguro AC, Shimizu MH, Otaduy MC, Sapienza MT, da Costa Leite C, Bonfá E, Lancha Junior AHCreatine supplementation does not impair kidney function in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trialEur J Appl Physiol.(2011 May)
23.^Taes YE, Delanghe JR, De Bacquer D, Langlois M, Stevens L, Geerolf I, Lameire NH, De Vriese ASCreatine supplementation does not decrease total plasma homocysteine in chronic hemodialysis patientsKidney Int.(2004 Dec)
24.^Shelmadine BD, Hudson GM, Buford TW et al.The effects of supplementation of creatine on total homocysteineJ Ren Nurs..(2012 Sep)