Creatinine is by-product of creatine. It is formed from creatine and excreted in the urine. In contrast to creatine, creatinine does not have any positive effect on physical performance during high-speed workouts and does not support muscle growth.
Creatinine or the creatinine level is used as a parameter for determining renal function during routine medical examinations. The normal creatinine level is dependent on the individual’s age, sex and physique, which is related to weight and muscle mass. For more information, see Standard creatinine level and What is creatinine?