Creatine is a compound mainly produced in the liver and then transferred to the body where it is used as a source of energy for muscle activity. Some creatine is spontaneously transformed into creatinine once in the muscle. The quantity of both creatine and creatinine is dependent on muscle mass, males usually have greater concentrations than females. Creatine is an available dietary supplement. If you take creatine, you may have greater values than if you do not take the supplement.