This systematic review investigates the effects of epicatechin (EC) on muscle atrophy in humans, animals, and myoblast cell lines. EC, a polyphenol found in tea and other foods, has shown potential in promoting skeletal muscle differentiation and counteracting protein degradation pathways. The review analyzed studies from Embase, PubMed/MEDLINE, Cochrane Library, and Web of Science, revealing that EC inhibits myostatin expression and atrogenes like MAFbx, FOXO, and MuRF1, while promoting follistatin and myogenic factors such as MyoD, Myf5, and myogenin. EC also enhances mitochondrial biogenesis, stimulates AKT/mTOR signaling, and improves skeletal muscle performance, especially when combined with physical exercise. However, the review highlights inconsistencies in study design, lack of standardized protocols, and limited clinical evidence, which hinder definitive conclusions about EC's therapeutic application. The review emphasizes the need for further research to standardize EC administration and explore its molecular mechanisms in muscle atrophy. Despite these limitations, EC shows promise as a potential treatment for muscle atrophy due to its beneficial effects on muscle function and regeneration. Future studies should focus on optimizing EC dosing, exploring its interactions with other compounds, and conducting rigorous clinical trials to validate its therapeutic potential.This systematic review investigates the effects of epicatechin (EC) on muscle atrophy in humans, animals, and myoblast cell lines. EC, a polyphenol found in tea and other foods, has shown potential in promoting skeletal muscle differentiation and counteracting protein degradation pathways. The review analyzed studies from Embase, PubMed/MEDLINE, Cochrane Library, and Web of Science, revealing that EC inhibits myostatin expression and atrogenes like MAFbx, FOXO, and MuRF1, while promoting follistatin and myogenic factors such as MyoD, Myf5, and myogenin. EC also enhances mitochondrial biogenesis, stimulates AKT/mTOR signaling, and improves skeletal muscle performance, especially when combined with physical exercise. However, the review highlights inconsistencies in study design, lack of standardized protocols, and limited clinical evidence, which hinder definitive conclusions about EC's therapeutic application. The review emphasizes the need for further research to standardize EC administration and explore its molecular mechanisms in muscle atrophy. Despite these limitations, EC shows promise as a potential treatment for muscle atrophy due to its beneficial effects on muscle function and regeneration. Future studies should focus on optimizing EC dosing, exploring its interactions with other compounds, and conducting rigorous clinical trials to validate its therapeutic potential.