Probiotic supplementation may improve muscle mass and strength but does not replace the need for protein intake. Protein remains important for muscle health, especially in older adults.
What the research shows
Multiple high-quality systematic reviews and meta-analyses indicate that probiotics can enhance muscle mass and muscle strength in adults, particularly older adults. Probiotic supplementation showed significant improvements in muscle mass and strength but did not significantly affect total lean mass. Specific strains such as Lactobacillus paracasei PS23 have demonstrated benefits in improving muscle strength and reducing inflammation in elderly populations. The gut-muscle axis is a promising area, with probiotics potentially modulating inflammation, metabolism, and muscle recovery. However, probiotics alone do not replace protein intake, which is essential for muscle mass maintenance and growth. High-protein diets have been shown to improve muscle mass, especially in women and with interventions lasting at least 12 weeks. Evidence supports combined nutritional strategies including protein and probiotics for optimal muscle health. Safety profiles of probiotics are generally good, with no major adverse effects reported in the studies analyzed. Limitations include heterogeneity in probiotic strains, doses, and study populations, as well as a need for more research on mechanisms and long-term effects.
Best studied probiotic strains
Lactobacillus paracasei PS23
Heat-treated PS23 showed more pronounced benefits in reducing inflammation and increasing testosterone levels.
Lactobacillus spp.
Effects are strain-specific and more research is needed to identify optimal strains and doses.
Who may benefit
Safety
Probiotic supplementation was generally safe with no significant adverse effects reported in the analyzed studies. Both live and heat-killed forms of Lactobacillus paracasei PS23 were well tolerated.
Limitations
Studies vary in probiotic strains, doses, duration, and populations studied. Most evidence focuses on older adults; effects in younger populations are less clear. Muscle mass improvements are modest and probiotics do not replace the need for adequate protein intake. More large-scale, long-term RCTs are needed to confirm findings and clarify mechanisms.
PubMed sources
| Study | Type | Year | PMID |
|---|---|---|---|
| Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials. Journal of cachexia, sarcopenia and muscle |
Meta-analysis | 2023 | 36414567 |
| Understanding the gut microbiota and sarcopenia: a systematic review. Journal of cachexia, sarcopenia and muscle |
Systematic Review | 2021 | 34523250 |
| Enhancement of Lower Limb Muscle Strength and Reduction of Inflammation in the Elderly: A Randomized, Double-Blind Clinical Trial Comparing PS23 Probiotic with Heat-Treated Supplementation. Nutrients |
Randomized Controlled Trial | 2025 | 39940321 |
| Effect of spp. Supplementation for Improving Muscle Health: A Systematic Review and Meta-Analysis. Journal of medicinal food |
Meta-analysis | 2025 | 40719617 |
| Live and Heat-Killed Probiotic PS23 Accelerated the Improvement and Recovery of Strength and Damage Biomarkers after Exercise-Induced Muscle Damage. Nutrients |
Randomized Controlled Trial | 2022 | 36364825 |
| The Effects of Pro-, Pre-, and Synbiotics on Muscle Wasting, a Systematic Review-Gut Permeability as Potential Treatment Target. Nutrients |
Systematic Review | 2021 | 33805286 |
| Effect of Probiotic Supplementation on Body Fat, Skeletal Muscle Mass, and Body Mass Index in Individuals ≥45 Years Old: A Systematic Review. In vivo (Athens, Greece) |
Systematic Review | 2025 | 40294995 |
| Effect of host and gut microbiota-altering interventions on sarcopenia or its defining parameters: a systematic review and meta-analysis of nutrition-based intervention studies. Aging clinical and experimental research |
Meta-analysis | 2025 | 41269489 |