The Gut Microbiota-Muscle Axis: Lactobacillus as a Potential Modulator of Skeletal Muscle Health

Skeletal muscle constitutes one of the largest tissue compartments in the human body and plays fundamental roles in locomotion, posture maintenance, and metabolic regulation. Muscle homeostasis requires a precise balance between protein synthesis and degradation pathways; disruption of this equilibrium leads to pathological conditions, including sarcopenia and muscle atrophy, which frequently coexist with metabolic disorders such as obesity, Type 2 diabetes mellitus, and metabolic syndrome. Recent advances have identified the gut microbiota as an important regulator of skeletal muscle health, positioning probiotics as potential therapeutic interventions. Among probiotic candidates, Lactobacillus species have been associated with improvements in muscle health through pleiotropic mechanisms, including attenuation of inflammatory signaling, enhancement of mitochondrial biogenesis, modulation of muscle protein turnover, and restoration of the intestinal microbial balance by enriching beneficial bacteria while suppressing pathogenic species. These multifaceted effects translate to improved exercise performance, amelioration of metabolic dysfunction, and prevention of muscle wasting. This review comprehensively evaluates the current evidence supporting Lactobacillus supplementation as a strategy to increase skeletal muscle health and function, examines the underlying molecular mechanisms, and identifies critical research priorities, including strain-specific characterization, well-controlled human clinical trials, and mechanistic investigations, to optimize probiotic-based interventions for muscle-related disorders.