On the plus side, using an ‘A’ through ‘F’ grading scale, the Mayo Clinic gives creatine an ‘A’ based on evidence suggesting this popular sports nutrition ingredient can help increase muscle mass, strength and total work during exercise.
But, according to the National Institutes of Health U.S. National Library of Medicine, creatine use does not seem to improve endurance exercise or the performance of highly trained athletes. It also might not be as effective for older adults.