The Gut–Muscle Axis in Sarcopenia: Mechanisms, Evidence Gaps and Translational Challenges

Sarcopenia is an age-related skeletal muscle disorder characterized by reduced muscle mass, strength, and physical performance, as well as increased risk of disability, hospitalization, and mortality. Emerging evidence suggests that gut microbiota alterations may contribute to muscle decline via a microbiota–gut–muscle axis, acting as a context-dependent modulator rather than a primary causal driver. This narrative review synthesizes mechanistic, clinical, and translational evidence linking gut