<![CDATA[Background: Obesity is a global public health problem whose prevalence continues to rise and is associated with various metabolic complications. Obesity is closely linked to gut microbiota dysbiosis, characterized by reduced microbial diversity, increased intestinal permeability, and low-grade chronic inflammation. Probiotics are considered to have potential as a complementary therapy because they can modulate the composition of the gut microbiota and improve metabolic health. However, evidence from randomized controlled trials (RCTs) regarding the effectiveness of probiotics still shows varying results due to differences in strains, doses, duration of intervention, and characteristics of the study subjects.Objectives: This review aimed to analyze the effects of probiotic supplementation on gut microbiota composition, markers of inflammation or intestinal permeability, and anthropometric and metabolic parameters in overweight and obese adults based on randomized controlled trials.Methods: A systematic literature review was conducted according to the PRISMA 2020 guidelines. A literature search was performed in PubMed, Scopus, Web of Science, and the Cochrane Library until April 2026. The included studies were randomized controlled trials involving overweight or obese adults who received probiotic supplementation compared to a placebo or control group. Study selection was performed independently by two reviewers. The risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and the data were synthesized narratively. Results: Of the 10 included studies, eight reported improvements in gut microbiota composition or diversity, six showed reductions in LPS or inflammatory markers, and nine reported improvements in at least one anthropometric or metabolic parameter (body weight, BMI, waist circumference, visceral fat, and lipid profile). However, the effects of probiotics were not consistent across all studies and were strongly influenced by the strain, dose, duration, and population characteristics.Conclusion: Probiotic supplementation has potential benefits for improving gut microbiota dysbiosis and obesity-related metabolic parameters. However, further large-scale studies with longer intervention durations are required to confirm the long-term efficacy and identify the most effective probiotic strains.]]>
