Creatine monohydrate is one of the most studied sports supplements, but the kidney question keeps popping up. The reason is understandable: Serum creatinine, a value used to estimate kidney function, may increase while taking it. The wrong step is to automatically treat every increase in creatinine as an injury.
It’s a perfect misunderstanding for social media: two almost identical words, a value highlighted in red in the analyzes and the feeling that the case is closed. In reality, the two most recent meta-analyses tell a less alarming and more interesting story. Creatinine moves slightly; filtration indicators, in the healthy adults studied, do not show a significant worsening. To understand why, we need to start from what the exam really measures.
The real question, therefore, is not whether the integrator can change a number on the report. He can do it. The question is whether that change corresponds to a loss of function, and whether the results obtained in healthy people can be applied to those who already have a pathology.
Creatine and creatinine are not the same thing
Creatine participates in the rapid recycling of ATP in muscles and other tissues. Some is converted into creatinine and eliminated through the kidneys. Creatinine is therefore both a product of metabolism and an indirect marker used in formulas that estimate eGFR, the glomerular filtration rate.
These formulas work well as screening tools, but are influenced by muscle mass, nutrition, and creatine intake. A muscular athlete can have a higher value than a sedentary person without having less efficient kidneys.
What the 2025 meta-analysis shows
The systematic review published in 2025 included 21 studies. Twelve studies contributed to the creatinine meta-analysis, with 177 participants in the creatine group and 263 in the control groups. The authors observed a small increase in creatinine, more evident in interventions of one week or less (mean difference 0.12 mg/dL) (1).
The decisive fact is that glomerular filtration was not significantly different. The authors interpret the change in creatinine as a predictable metabolic consequence, not as evidence of renal damage. The quality and duration of the studies, however, do not allow us to erase all uncertainty in the very long term.
What the 2026 meta-analysis adds
The 2026 synthesis selected 19 randomized studies and one crossover study. Creatinine was on average 0.13 mg/dL higher (95% CI 0.07–0.18). For urea, the mean difference was -0.60 mg/dL and the confidence interval crossed zero. The difference in eGFR of -5.20 mL/min/1.73 m² was also not statistically significant because the range was -15.00 to 4.60 (2).
Simply put: the biomarker most directly linked to creatine metabolism moves slightly; the other indicators do not show a significant worsening. However, the authors call for more randomized studies lasting more than one year.
To whom do these results apply?
The conclusions are strongest for healthy adults using creatine monohydrate at controlled doses. It is not correct to automatically transfer them to the person presenting:
In these cases the decision must be clinical. “There is no evidence of harm in healthy adults” does not mean “safe for any pathology”.
Dose and form with more data
The International Society of Sports Nutrition review lists creatine monohydrate as the form with the most studies (3). For daily use, the literature often takes 3–5 grams per day. A loading phase of approximately 20 grams, divided into several intakes for 5–7 days, accelerates saturation but is not necessary.
Higher doses do not guarantee better results and increase the likelihood of gastrointestinal disorders. A Creapure creatine monohydrate allows you to identify the raw material; the declared dose, traceability and the absence of opaque mixtures remain essential.
How to read exams without alarmism
- Tell your doctor the dose, duration and date of last intake.
- Do not interpret a single creatinine without comparing it to previous values.
- Evaluate, when indicated, urinalysis, albumin-creatinine ratio and eGFR trend.
- In doubtful cases, the doctor may consider markers less influenced by muscle mass, such as cystatin C.
Stopping the supplement yourself a few days before the analysis can make the data less understandable. It is more useful to state the usage and let the practitioner choose how to interpret it.
When a medical evaluation is needed
Persistent swelling, marked reduction in urine, blood in the urine, lower back pain, unexplained nausea or very high blood pressure cannot be managed by changing brands or drinking excessive amounts of water. They require an evaluation.
A laboratory value is not a diagnosis
In healthy adults, creatine monohydrate may slightly increase creatinine without significantly reducing renal filtration. The two most recent meta-analyses converge on this point, while reporting the need for longer data. The correct answer is not to ignore the tests, but to interpret them knowing that supplementation modifies creatinine metabolism.
This article is for informational purposes and does not replace your doctor’s evaluation.
Sources
- Systematic review and meta-analysis on creatine supplementation and kidney function. 2025. PubMed.
- Meta-analysis of randomized trials on renal biomarkers during creatine supplementation. 2026. PubMed.
- Antonio J et al. Common questions and misconceptions about creatine supplementation. JISSN, 2021. Full text.
- Persky AM et al. Risk assessment of creatine monohydrate. 2006. PubMed.
