Postbiotics and Skeletal Muscle Health: Molecular Mechanisms and Translational Perspectives

Recent evidence implicates the gut microbiota in muscle physiology and function via the gut–muscle axis, which portrays bidirectional communication between microbial colonies, their metabolites and muscle tissue. Age-related muscle decline, including sarcopenia and muscle atrophy, has been associated with shifts in gut microbiota composition and lower levels of microbial metabolites, such as short-chain fatty acids (SCFAs), thereby expanding muscle health research toward microbiota-based therapies. Postbiotics, defined as preparations of inanimate microorganisms and/or their components, are gaining attention as a novel approach to combating muscle decline through modulation of microbiota–host communication, yet a comprehensive review of this topic is currently lacking. Preclinical studies demonstrate that postbiotics may exert anabolic effects while attenuating catabolism, inflammation, and cellular senescence, with associated improvements in grip strength, endurance capacity, and muscle morphology. Although clinical evidence remains limited, available studies indicate that postbiotics may have beneficial effects on muscle strength, endurance, and overall physical performance in humans. By synthesizing recent preclinical and clinical evidence, this review addresses an important gap in the literature, offering a comprehensive and mechanistically informed perspective on the potential role of postbiotics in modulating muscle health, particularly in the context of sarcopenia- and atrophy-associated muscle phenotypes.