However, If you reveal to that doctor that you're supplementing Creatine it will not be concern them.
Edit: see comment below (i.e. better to stop taking creatine at least a week before a test).
EDIT: I don't do 25g though... sounds like a lot...
Precisely and correctly as they said, normal eGFR presumes average musculature and average creatine consumption. If either of these out of the norm, eGFR becomes inaccurate and potentially flagging false positives for damage. Creatinine, the waste product of creatine, raises in a way that can get confused with kidney damage, which is precisely how the confusion about it causing kidney damage or being bad if you have a compromised kidney came about.
In some studies, people with CKD actually improved with creatine supplementation, though notably this was not people with PKD where it could increase cyst growth.
Creatine metabolizes into creatinine which is major indicator of kidney function because not being able to clear creatinine means your kidneys aren’t working. Adding more creatinine to your system decreases your ability to clear it leading to fatigue, edema, high blood pressure etc.
So it isn’t bad for your kidneys: it is bad for everything else.
Creatinine itself doesn't cause fatigue, edema, or high blood pressure. Kidney disease does.
Or more correctly, the myth saved his life.
Perhaps sometimes we should listen to conspiracy theorists. /s
