Role of Probiotics in Managing Acne Vulgaris: A Systematic Review and Meta-Analysis of Clinical Trials

Background: Dysregulation of the skin microbiome is implicated in acne pathogenesis. Objective: To evaluate the efficacy of probiotics in the management of acne. Methods: Searches were conducted in 3 databases through June 30, 2024. Clinical trials that compared probiotics with controls and investigated their efficacy in acne were included. Primary outcomes were standardized mean differences (SMDs) for the change from baseline to posttreatment in total lesion count (TLC), noninflammatory lesion count (NILC), and inflammatory lesion count (ILC). Secondary outcomes included Global Acne Grading System (GAGS) scores, Investigator’s Global Assessment, erythema, and sebum levels. Results: Thirteen studies comprising 18 study arms and 1453 participants were included. There were no significant reductions in TLC (SMD, −0.22; 95% confidence interval [CI]: −0.50 to 0.07; I² = 75%), NILC (SMD, −0.20; 95% CI: −0.48 to 0.08; I² = 72%), or ILC (SMD, −0.13; 95% CI: −0.34 to 0.09; I² = 52%) with probiotics compared with controls. However, oral probiotics were associated with a significant reduction in GAGS scores (SMD, −0.47; 95% CI: −0.81 to −0.13; I² = 67%) versus controls. Subgroup analyses indicated that this effect was most prominent in mild-to-moderate acne patients who received oral probiotics containing Lactobacillus species combined with other strains for a minimum of 12 weeks. Conclusions: Probiotics did not demonstrate a significant reduction in acne lesion counts. However, they were associated with improvements in acne severity as measured by GAGS scores. These findings should be interpreted with caution given the heterogeneity across studies and the fluctuating natural course of acne.