The Claim
Six weeks of combined creatine monohydrate and guanidinoacetic acid supplementation at 10 g/day and 2 g/day, respectively, results in a statistically significant decrease in estimated glomerular filtration rate (eGFR) by 7.5 mL/min/1.73m², which is attributable to increased creatinine production rather than true kidney impairment.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Taking 10 grams of creatine monohydrate and 2 grams of guanidinoacetic acid daily for six weeks lowers the estimated glomerular filtration rate by 7.5 mL/min/1.73m² due to higher creatinine levels, not because the kidneys are damaged.
See the scientific wording
Six weeks of combined creatine monohydrate and guanidinoacetic acid supplementation (10 g/day + 2 g/day) leads to a statistically significant decrease in estimated glomerular filtration rate (eGFR) by 7.5 mL/min/1.73m², but this change is likely an artifact of increased creatinine production and does not reflect true kidney impairment.
Supplementing with creatine and guanidinoacetic acid causes the body to make more creatinine, a waste product that kidney tests measure. Higher creatinine levels trick the formula used to estimate kidney function into showing a lower number, even though the kidneys are filtering just as well as before.
What the research says
1 studyTaking creatine and GAA together made a kidney test look worse, but that’s because the supplements made more creatinine — not because the kidneys got damaged. All other health markers stayed normal.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.