Based on multiple scientific studies, there is no convincing evidence that creatine is bad for your kidneys in healthy adults. RCT studies and systematic reviews primarily show that creatine can slightly increase serum creatinine, while more direct measures of kidney function usually remain stable. Therefore, it is important to distinguish between an altered blood value and actual kidney damage. This distinction largely determines the entire answer to this question. (Naeini et al., 2025; de Souza e Silva et al., 2019).
Is creatine bad for your kidneys?
The strongest line of research is quite consistent. In the available human RCTs and systematic reviews, no clear deterioration of glomerular filtration, creatinine clearance, albuminuria or proteinuria is observed with standard oral creatine protocols. This applies not only to healthy adults, but also to several controlled subgroups studied, such as postmenopausal women, people with type 2 diabetes, and adults with peripheral arterial disease. (Naeini et al., 2025; de Souza e Silva et al., 2019; Neves et al., 2011; Gualano et al., 2011; Domingues et al., 2020).
The confusion mainly arises around serum creatinine. Creatinine is not a pure damage parameter. It is also a breakdown product of creatine and muscle metabolism. As a result, creatine use can increase serum creatinine without the kidney's filtration function actually deteriorating. If a laboratory subsequently calculates eGFR based on creatinine, that eGFR may appear lower, while in reality there is no evidence of true kidney damage. This is explicitly mentioned in the recent synthesis as an interpretation problem, not as hard evidence of harm. (Naeini et al., 2025).
This pattern is also reflected in individual trials. In the RCT by de Oliveira Vilar Neto et al., serum creatinine increased within the creatine groups and eGFR decreased, but there were no significant differences between the groups. At the same time, more sensitive kidney damage markers such as KIM-1 and MCP-1, as well as albuminuria and proteinuria, remained unchanged. This is more consistent with a laboratory effect than with actual kidney damage. (de Oliveira Vilar Neto et al., 2020).
The most cautious conclusion is therefore: in healthy adults, the evidence is strongly reassuring; for serum creatinine alone, the evidence is mixed; and for people with existing chronic kidney disease or other complex medical situations, the evidence is limited. Precisely there, larger, long-term RCTs are lacking. (Naeini et al., 2025).
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What is creatine?
Creatine is a nitrogen-containing compound that the body can produce itself from amino acids and which also comes from food. In muscle tissue, creatine, especially as phosphocreatine, plays a role in rapid energy buffering and ATP resynthesis during short, intense exercise. For the kidney story, it is particularly important that creatine and creatinine are biochemically related. Part of the ingested or stored creatine is converted into creatinine. As a result, creatine supplementation and creatinine-based kidney measurements can influence each other, without there necessarily being renal damage directly. (Naeini et al., 2025).
In the kidney safety literature used here, it almost always concerns creatine monohydrate in oral form. This is relevant, because statements about creatine kidneys based on this evidence thus mainly refer to creatine monohydrate, and not to all kinds of other creatine forms or combination products. (Naeini et al., 2025).
How much creatine should you take per kg of body weight?
In the literature, two main approaches are used: an absolute daily dosage and a relative dosage per kilogram of body weight. The best-studied relative loading phase is around 0.3 g per kg of body weight per day. After that, the relative maintenance range in systematic protocols is around 0.03 to 0.14 g/kg/d. In absolute terms, a classic loading phase is usually described as approximately 20 grams per day for 5 to 7 days, followed by a maintenance phase of 2 to 5 grams per day. There are also protocols without a loading phase, for example 3 grams per day, where saturation occurs more slowly. (Pashayee-Khamene et al., 2024; Wang et al., 2024).
The kidney-focused RCTs align well with this pattern. There are studies with 0.3 g/kg/d in the first week, followed by 0.15 g/kg/d for eleven weeks, but also trials with 3 or 5 grams per day without a loading phase. Other studies used the classic approach of 20 grams per day for a week and then 5 grams per day for seven to twelve weeks. Based on these studies, there is no consistent signal that standard loading protocols within this range impair kidney function, as long as you do not derive the outcome solely from serum creatinine. (Gualano et al., 2008; Neves et al., 2011; Domingues et al., 2020; de Oliveira Vilar Neto et al., 2020).
Conclusion: is creatine bad for your kidneys?
Based on the available RCTs and systematic reviews, the most defensible conclusion is that creatine is not convincingly associated with kidney function deterioration in healthy adults. The literature does not show a consistent decrease in measured or estimated filtration that holds up when also considering more direct or additional markers such as creatinine clearance, albuminuria, proteinuria, or more sensitive biomarkers. What is observed, however, is that creatine can slightly increase serum creatinine. This can cause creatinine-based eGFR to appear lower, which does not automatically mean that the kidneys are damaged. (Naeini et al., 2025; de Souza e Silva et al., 2019).
Thus, the answer to the question "is creatine bad for your kidneys?" for healthy adults is quite clear: the evidence does not support it. For people with pre-existing chronic kidney disease or other complex medical situations, caution remains logical, especially since less direct RCT data is available for these groups. This is primarily a knowledge gap, not convincing evidence of harm caused by creatine itself. (Naeini et al., 2025).
Sources
Almeida, D., Colombini, A., & Machado, M. (2020). Creatine supplementation improves performance, but is it safe? Double-blind placebo-controlled study. Journal of Sports Medicine and Physical Fitness, 60(7), 1034–1039.
de Oliveira Vilar Neto, J., da Silva, C. A., Meneses, G. C., et al. (2020). Novel renal biomarkers show that creatine supplementation is safe: A double-blind, placebo-controlled randomized clinical trial. Toxicology Research, 9(3), 263–270.
de Souza e Silva, A., Pertille, A., Reis Barbosa, C. G., de Oliveira Silva, J. A., de Jesus, D. V., Ribeiro, A. G. S. V., Baganha, R. J., & de Oliveira, J. J. (2019). Effects of creatine supplementation on renal function: A systematic review and meta-analysis. Journal of Renal Nutrition, 29(6), 480–489.
Domingues, W. J. R., Ritti-Dias, R. M., Cucato, G. G., et al. (2020). Does creatine supplementation affect renal function in patients with peripheral artery disease? A randomized, double-blind, placebo-controlled clinical trial. Annals of Vascular Surgery, 63, 45–52.
Gualano, B., de Salles Painelli, V., Roschel, H., et al. (2011). Creatine supplementation does not impair kidney function in type 2 diabetic patients: A randomized, double-blind, placebo-controlled, clinical trial. European Journal of Applied Physiology, 111(5), 749–756.
Gualano, B., Ugrinowitsch, C., Novaes, R. B., et al. (2008). Effects of creatine supplementation on renal function: A randomized, double-blind, placebo-controlled clinical trial. European Journal of Applied Physiology, 103(1), 33–40.
Lugaresi, R., Leme, M., de Salles Painelli, V., et al. (2013). Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet? Journal of the International Society of Sports Nutrition, 10, 26.
Naeini, E. K., Eskandari, M., Mortazavi, M., et al. (2025). Effect of creatine supplementation on kidney function: A systematic review and meta-analysis. BMC Nephrology, 26, 622.
Neves, M., Jr., Gualano, B., Roschel, H., et al. (2011). Effect of creatine supplementation on measured glomerular filtration rate in postmenopausal women. Applied Physiology, Nutrition, and Metabolism, 36(3), 419–422.
Pashayee-Khamene, F., Heidari, Z., Ghanavati, M., et al. (2024). Creatine supplementation protocols with or without training interventions on body composition: A GRADE-assessed systematic review and dose-response meta-analysis. Journal of the International Society of Sports Nutrition, 21(1), 2380058.
Wang, Z., Qiu, B., Li, R., et al. (2024). Effects of creatine supplementation and resistance training on muscle strength gains in adults <50 years of age: A systematic review and meta-analysis. Nutrients, 16(21), 3665.
