Comment by nerevarthelame

Creatinine can be an indicator that your kidneys are not working well. It's a cheap red flag that can be screened for in a common blood test. But if heightened creatinine is a result of one's creatine supplementation, then there are none of the downsides associated with kidney disease.

Creatinine itself doesn't cause fatigue, edema, or high blood pressure. Kidney disease does.