For a serious gym personnel, the more you train, the more your muscles releases this muscle enzyme called Creatine Kinase, due to the temporal injuries you inflict on the muscle tissues with the weights, which causes the CK level to elevate ‘temporarily’. But if your recovery protocols are great enough, then the elevation is gonna drop down in few days, or week(s). As for creatine supplement causing creatine kinase level to rise, that’s mostly untrue. I think most people confuse serum creatinine

Creatine Side Effects, Interactions, and What You Should Know