Probiotic supplementation may help improve muscle strength and muscle mass, especially in older adults, but it does not replace the need for adequate protein intake. Specific probiotic strains like Lactobacillus paracasei PS23 show promise in enhancing muscle strength and reducing inflammation.
What the research shows
Multiple high-quality systematic reviews and meta-analyses indicate that probiotics can improve muscle strength and muscle mass in adults, particularly older adults. Probiotic supplementation showed significant improvements in muscle strength (e.g., handgrip strength, gait speed) and muscle mass, although effects on total lean mass were inconsistent. Lactobacillus paracasei PS23, both live and heat-killed forms, demonstrated benefits in enhancing lower limb muscle strength, reducing inflammation, and accelerating recovery after muscle damage. Evidence also suggests that probiotics may modulate the gut-muscle axis, influencing muscle metabolism and inflammation. However, the optimal strains, doses, and duration of probiotic supplementation remain to be clarified. Probiotics are not a substitute for protein intake but may complement nutritional strategies to support muscle health.
Best studied probiotic strains
Lactobacillus paracasei PS23
Heat-killed PS23 showed more pronounced benefits in some outcomes. Supplementation duration was 6-12 weeks in elderly populations.
Lactobacillus (general)
Effects are strain-specific and more research is needed to identify the most effective strains.
Who may benefit
Safety
Probiotic supplementation, including Lactobacillus paracasei PS23, was well tolerated in clinical trials with no significant adverse effects reported. Heat-killed probiotics may offer a safe alternative with similar benefits.
Limitations
Most studies focus on older adults; evidence in younger populations is limited. Optimal probiotic strains, doses, and treatment durations are not fully established. Probiotics alone do not replace the need for adequate protein intake or other nutritional and exercise interventions. Some meta-analyses showed no significant effects on total lean mass. More high-quality 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 |
| 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 |
| Effect of spp. Supplementation for Improving Muscle Health: A Systematic Review and Meta-Analysis. Journal of medicinal food |
Meta-analysis | 2025 | 40719617 |
| 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 |
| Effects of Probiotics, Prebiotics, and Synbiotics on Sarcopenia Parameters in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrition reviews |
Meta-analysis | 2025 | 39405177 |