Abstract
INTRODUCTION: Microbiome-modulating therapies including prebiotics, probiotics, and postbiotics have been increasingly investigated as adjuncts or alternatives for managing acne vulgaris through effects on the gut-skin axis, inflammation, and barrier function. The objective of this systematic review is to characterize the safety and efficacy of oral and topical prebiotics, probiotics, and postbiotics in managing acne vulgaris. METHODS: We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review of randomized controlled trials, cohort studies, and case-control studies evaluating oral and topical prebiotics, probiotics, and postbiotics for acne vulgaris from inception to August 2025 in PubMed, Embase, Web of Science, and Cochrane. Inclusion criteria comprised clinical studies reporting on safety and/or efficacy of topical and/or oral prebiotic, probiotic, and postbiotic therapy in patients with acne vulgaris. RESULTS: In total, 33 studies evaluating 2112 total patients were included, with treatment durations of 4-25 weeks; 5 prebiotic, 24 probiotic, and 7 postbiotic studies were included, with 2 studies comparing prebiotics and probiotics and 1 study comparing prebiotics and postbiotics against each other. Safety was favorable across all modalities with no serious adverse events reported. Pooled mean total lesion reductions were -37.2% for prebiotics, -45.2% for probiotics, and -49.5% for postbiotics, versus -37% for controls. CONCLUSIONS: Prebiotic, probiotic, and postbiotic therapies appear to be safe and associated with clinically meaningful lesion reductions in acne. They may increase tolerability and add additional efficacy to standard acne treatments including topical and oral antibiotics and retinoids. Probiotics currently have the strongest evidence base, while prebiotics and postbiotics are promising adjuncts. Larger, standardized randomized trials are needed to clarify comparative efficacy, optimal formulations, and durability.