Comparative analysis of the efficacies of probiotic supplementation and glucose-lowering drugs for the treatment of type 2 diabetes: A systematic review and meta-analysis

Systematic review and meta-analysis of randomized studies in adults with type 2 diabetes from multiple countries. The evidence base included 14 probiotic arms (N=842) and 11 glucose-lowering drug arms (N=2001), with outcomes spanning glycemic control, insulin resistance, lipids, and blood pressure.

Oral probiotic supplementation was evaluated in multiple formulations, including capsules, sachets, synbiotic food, soy milk, kefir, and fermented milk products. Reported doses ranged from 1×10^7 to 3×10^10 cfu, or from 120 g/day to 600 mL/day of fermented products, typically given for 6 to 12 weeks, and compared with glucose-lowering drugs in the review.

Glucose-lowering drugs generally produced larger reductions in fasting blood glucose and HbA1c than probiotics, with GLP-1 receptor agonists and SGLT-2 inhibitors showing the strongest glycemic effects. Probiotic supplementation still showed beneficial metabolic effects, especially milder improvements in glycemic indices, insulin resistance, and lipid profiles. Probiotics were also associated with reductions in systolic and diastolic blood pressure, and some formulations lowered total cholesterol and triglycerides. Overall, probiotics may be more useful as an adjunct or for less severe type 2 diabetes, whereas glucose-lowering drugs remain the primary treatment for more severe disease.

The included evidence had substantial heterogeneity, reflecting different probiotic strains, delivery forms, doses, and short treatment durations of about 6 to 12 weeks. Adverse event reporting was inconsistent, and arm-specific effect sizes were not provided in the source packet. The review therefore supports only cautious interpretation and limited generalizability across probiotic regimens and patient populations.