Pea-Derived Protein Supplementation in Sports and Exercise Nutrition: A Narrative Review of Muscle Protein Synthesis and Training Adaptations

Background: Plant-derived proteins are increasingly prominent in sports nutrition, yet pea protein (Pisum sativum) is often confounded with multi-ingredient blends or fortified formulations. This narrative review evaluates human and preclinical evidence on pea protein in skeletal muscle anabolism, exercise recovery, and training adaptations. Methods: MEDLINE, Scopus, and Web of Science were searched up to September 2026. Thirty-three studies (24 human, 8 animal, 1 in vitro) were stratified by experimental model, intervention directness (isolated pea protein vs. blends/adjuncts), and physiological endpoints. Results: Isolated pea protein stimulates postprandial muscle protein synthesis (MPS) under specific conditions, despite lower early peak leucine and essential amino acid concentrations than whey. Longitudinal resistance-training trials report improvements in muscle mass and strength with pea protein; however, available data do not establish an added benefit over training alone or formal equivalence/non-inferiority to whey. Preclinical models suggest potential anti-atrophic bioactivity of specific pea peptides. Conclusions: Isolated pea protein supports postprandial MPS and resistance-training adaptations. However, current evidence is insufficient to establish equivalence to dairy proteins. Powered trials with prespecified non-inferiority margins are needed.