This systematic review examines the effects of epicatechin (EC), a polyphenol compound, on muscle atrophy in humans, animals, and myoblast cell lines. EC promotes skeletal muscle differentiation and counteracts protein degradation pathways. The review found that EC inhibits myostatin expression and atrogenes (MAFB, FOXO, MuRF1), while stimulating follistatin and myogenic factors (MyoD, Myf5, myogenin). EC also interferes with mitochondrial biosynthesis, activates the AKT/mTOR signaling pathway, and improves skeletal muscle performance, especially when combined with physical exercise. Despite positive findings, there is a lack of standardized protocols and clinical evidence to fully support its therapeutic implementation. The review highlights the need for further research to standardize protocols and conduct rigorous clinical trials to validate EC's therapeutic applicability in muscular atrophy.This systematic review examines the effects of epicatechin (EC), a polyphenol compound, on muscle atrophy in humans, animals, and myoblast cell lines. EC promotes skeletal muscle differentiation and counteracts protein degradation pathways. The review found that EC inhibits myostatin expression and atrogenes (MAFB, FOXO, MuRF1), while stimulating follistatin and myogenic factors (MyoD, Myf5, myogenin). EC also interferes with mitochondrial biosynthesis, activates the AKT/mTOR signaling pathway, and improves skeletal muscle performance, especially when combined with physical exercise. Despite positive findings, there is a lack of standardized protocols and clinical evidence to fully support its therapeutic implementation. The review highlights the need for further research to standardize protocols and conduct rigorous clinical trials to validate EC's therapeutic applicability in muscular atrophy.