Creatine isn’t harming your kidneys The idea that it does stems from a common metabolic byproduct: creatinine When you supplement with creatine, some of it naturally metabolizes into creatinine (which standard lab tests flag as a possible sign of kidney dysfunction) So if you’re supplementing with creatine, higher blood creatinine is expected and harmless (it’s not kidney damage) For a much more accurate picture of kidney function, consider measuring cystatin C - Watch our deep dive episode on c