Can creatine (creatine monohydrate) supplements increase serum creatinine levels, indicating impaired renal function?

From the Guidelines

Yes, creatine supplements can raise creatinine levels in the blood, as creatine is converted to creatinine in the body as part of normal metabolism, leading to higher creatinine levels, as noted in recent studies 1. This elevation is generally temporary and occurs because the body is processing more creatine than usual. The increase in creatinine is usually modest, ranging from 0.2 to 0.6 mg/dL above baseline, and depends on the dosage of creatine taken. Key points to consider include:

• The effect of creatine supplements on creatinine levels is important to know if you're getting blood tests, as elevated creatinine is normally used as a marker for kidney function, with studies indicating that serum creatinine levels can be influenced by various factors including muscle mass and diet 2.
• When the elevation is due to creatine supplementation rather than kidney problems, it's considered a benign finding, and recent guidelines suggest that minor increases in serum creatinine should not lead to discontinuation of certain medications without other indications 3.
• If you're taking creatine supplements and need to have kidney function tests, it's advisable to inform your healthcare provider about your supplement use, and you might consider temporarily stopping creatine supplementation 1-2 weeks before scheduled blood work if accurate creatinine measurement is important for your medical care. Some important considerations in the context of kidney function and creatinine levels include:
• The definition and stages of chronic kidney disease (CKD), with CKD being defined as an abnormality of kidney structure or function, present for >3 months, with health consequences, and five stages based on estimated GFR calculated using serum creatinine and standard equations 1.
• The evaluation of patients with CKD, which includes a thorough history, physical examination, laboratory, and serologic workups, with markers of kidney damage including measurement of albuminuria and urinary sediment, and abnormal histology on kidney biopsy or structural abnormalities on imaging also qualifying as CKD 1.

From the Research

Creatine Supplements and Creatinine Levels

• Creatine supplements may increase serum creatinine levels, but this does not necessarily indicate kidney dysfunction, as creatine is spontaneously converted into creatinine 4, 5.
• The increase in serum creatinine levels due to creatine supplementation can lead to overdiagnosis of chronic renal failure, especially if clinical laboratories rely solely on serum creatinine to estimate glomerular filtration rate 5.
• Studies have shown that creatine supplementation does not significantly alter serum creatinine levels in healthy individuals 6.

Safety of Creatine Supplementation

• Creatine supplementation appears to be safe for healthy adults when used at recommended doses, but may be associated with an increased risk of renal dysfunction in individuals with pre-existing kidney disease or those taking nephrotoxic medications 7, 4.
• There is limited evidence on the long-term use of creatine supplementation in doses exceeding 10 gm/day, and the safety of creatine in children and adolescents has not been established 7.
• Reports of kidney damage associated with creatine supplementation are scarce, and most studies suggest that creatine supplements do not cause renal disease 5, 6.

Assessment of Kidney Function

• Serum creatinine is a commonly used biomarker for assessing kidney function, but its use may be limited in individuals taking creatine supplements, as it can lead to false indicators of renal dysfunction 7, 8.
• More accurate equations, such as the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, have been introduced to estimate kidney function, and may be useful in managing healthcare for patients with chronic kidney disease 8.