Abstract

Protein (PRO) and creatine (Cr) supplementation are both purported dietary strategies to enhance resistance training (RT) gains in muscular strength and lean tissue mass (LTM). PROs that contain all essential amino acids, have a high concentration of leucine, and are rapidly absorbed provide the greatest increase in muscle PRO synthesis. Cr acts as a pleiotropic molecule within the muscle and plays a critical role as an energy buffer. Coingestion of PRO with Cr may act synergistically and further enhance RT adaptations. The purpose of this narrative review is to summarize recent evidence exploring PRO and Cr supplementation combined with RT on muscular strength and LTM. PRO and Cr supplemented individually appear to have a small but positive effect on RT gains in LTM (PRO = 0.3 kg; Cr = 0.99 kg) and strength (PRO = 2.49 kg; Cr = upper body 4.43 kg, lower body 11.35 kg) compared with placebo (PLA). Cosupplementation of PRO and Cr has been shown to further enhance RT gains in LTM (Cr + PRO = 4.0 kg; PRO = 2.3 kg) and whole-body strength (Cr + PRO = 20.5 kg; PRO = 14.4 kg) compared with PRO alone; however, individual studies did not find any further benefit of coingestion compared with Cr alone. In summary, for individuals engaged in RT, achieving a daily PRO intake via supplementation (>1.6-2.0 g/kg/d) and Cr (∼0.1 g/kg/d) individually is effective to augment gains in LTM and strength. Coingestion of Cr and PRO further enhances RT gains compared with PRO alone; however, if ingesting sufficient daily PRO, only Cr supplementation appears to be effective.