Creatine: ergogenic aid with antioxidant potential?

Abstract

Creatine is largely used as an ergogenic aid with some evidence regarding its positive effect on lean body mass, strength/power and muscle endurance. However, most studies were not capable of identifying biochemical mechanisms that could explain its effect on fatigue or muscle protein turnover. There is also the possibility that some individuals are non-responsive to this supplement. Another possible effect of creatine that has been recently investigated is its antioxidant action, but few studies explored this subject. Nonetheless, it can be emphasized that the antioxidant effect of creatine works in the organism in the following way: 1) Indirect
action as an energy buffer, due to the increase in muscle phosphocreatine concentrations which would favor a reduced production of metabolites of the purine nucleotide cycle (cycle of Lowenstein) and, as a consequence, a drop in the production of hypoxanthine, xanthine, uric acid, and reactive oxygen species; 2) Direct action (a less powerful action when compared with known antioxidants, such as reduced glutathione). Yet, it could still work in association with them. The objective of this work is to review the available data on the two abovementioned mechanisms.