From the Guidelines
Creatine supplementation is not harmful to kidney function in healthy individuals, and its use does not lead to nephrotoxicity, as evidenced by a study published in 2020 in the American Journal of Kidney Diseases 1. When considering the use of creatine supplements, it is essential to understand the distinction between creatine and creatinine, as creatinine is a waste product filtered by the kidneys and used as a marker for kidney function in blood tests.
- The metabolism of creatine produces creatinine, which can temporarily increase creatinine levels in the blood, but this elevation does not reflect kidney damage.
- A unique situation of using creatine supplementation in a patient with a solitary kidney showed that creatine did not alter kidney function, although creatinine clearance measurements were incorrect, leading to a misclassification of acute kidney injury due to influences of creatine supplementation on creatinine clearance measurements 1.
- The study highlights the importance of considering the potential effects of dietary supplements on kidney function, particularly in individuals with pre-existing kidney disease or impaired kidney function.
- However, for healthy individuals, creatine supplementation poses no risk to kidney health, and staying well-hydrated, following recommended dosages, and considering occasional breaks from supplementation are essential to using creatine safely.
- It is also crucial to note that the concern about creatine and kidneys stems from the fact that creatine metabolism produces creatinine, but studies following creatine users for years have not found evidence of kidney harm in healthy individuals 1.
From the Research
Effects of Creatine on Kidney Function
- Creatine supplementation may increase serum creatinine concentration, but it does not necessarily indicate kidney dysfunction, as creatine is spontaneously converted into creatinine 2.
- Clinical trials with controlled designs do not support the claim that creatine impairs kidney function 2, 3.
- Creatine supplements are safe and do not cause renal disease, but reports of kidney damage associated with its use are scanty 3.
- Creatine may decrease renal function, but only two case reports of this effect have been published 4.
Safety of Creatine Supplementation
- Creatine appears to be well tolerated in short-term trials, with few adverse effects reported 4, 5.
- The most common adverse effect is transient water retention in the early stages of supplementation 5.
- When combined with other supplements or taken at higher than recommended doses for several months, there have been cases of liver and renal complications with creatine 5.
Special Considerations for Individuals with Kidney Disease
- Creatine supplements should not be used in people with chronic renal disease or using potentially nephrotoxic medications 3.
- Individuals with chronic kidney disease may require creatine supplementation due to decreased endogenous production of creatine 6.
- A low-protein diet may lead to creatine deficiency in patients with non-dialysis-dependent chronic kidney disease, making creatine a conditionally essential nutrient 6.