Efficacy and safety of probiotic/synbiotic supplementation for osteoporosis: a meta-analysis of randomized controlled trials

Objectives To evaluate the efficacy and safety of probiotic/synbiotic supplementation for osteoporosis. Methods PubMed, Embase, Web of Science, and Cochrane databases were used to screen studies up to October 2025. Data pooling used standardized mean differences (SMD) or risk ratios (RR) with 95% confidence intervals (CI). Sensitivity analysis assessed result stability. Review Manager 5.4 and STATA 15.1 were used to analyze. Publication bias was assessed by Egger’s test and funnel plots. Evidence for each outcome was evaluated and graded according to GRADE. Results Ten randomized controlled trials (RCTs) with 732 patients were included. Significant improvements in lumbar spine bone mineral density (BMD) (SMD: 0.85; 95% CI: 0.01, 1.69; P = 0.049) and parathyroid hormone (SMD: −1.21; 95% CI: −2.19, −0.23; P = 0.02) existed in the probiotic/synbiotic group. No increase in adverse event risk was observed (RR: 1.03; 95% CI: 0.86, 1.23; P = 0.78). No significant effects were found on total hip BMD, osteocalcin, C-terminal telopeptide, alkaline phosphatase, or osteoprotegerin. No publication bias was detected. Conclusion Probiotic/synbiotic supplementation may be safe and effective as an adjunctive treatment for osteoporosis, improving bone density without increasing adverse reactions. Larger, multicenter RCTs are needed to confirm these findings. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/view/CRD42024540614 , identifier CRD42024540614.