Probiotic supplementation may improve muscle strength and muscle mass to some extent, but it does not replace the need for adequate protein intake. Probiotics can be a supportive strategy, especially for older adults or those with muscle loss, but protein remains essential for muscle health.
Multiple high-quality meta-analyses and randomized controlled trials indicate that probiotics can improve muscle strength and muscle mass, particularly in older adults. Probiotic supplementation showed significant improvements in muscle strength (e.g., handgrip strength, gait speed) and muscle mass in some studies, although effects on total lean mass were generally not significant. Specific strains such as Lactobacillus paracasei PS23 have demonstrated benefits in reducing inflammation and accelerating recovery after muscle damage. The evidence suggests probiotics may support muscle health via the gut-muscle axis, potentially through mechanisms involving reduced inflammation and improved metabolism. However, probiotics alone do not significantly increase muscle mass without adequate protein intake. Nutritional strategies combining protein and probiotics may optimize muscle function, especially in aging populations. More research is needed to identify the best strains, doses, and combinations with protein.
Heat-treated PS23 showed more pronounced benefits in elderly adults.
Effects are strain-specific and combined with other nutritional interventions.
Probiotic supplementation, including Lactobacillus paracasei PS23, was well tolerated in clinical trials with no significant adverse effects reported. Heat-killed probiotic forms also appear safe and effective.
Most studies do not specify probiotic strains or doses clearly, limiting strain-specific recommendations. Effects on total lean mass are inconsistent. Evidence on prebiotics and synbiotics is limited and mixed. Many studies focus on older adults, so generalizability to younger populations is uncertain. Probiotics should not replace adequate protein intake, which is essential for muscle health. More high-quality RCTs are needed to confirm optimal strains, doses, and combinations with protein.