Yen H, Chang YT, Yee FJ, et al. - In this systematic review and meta-analysis, researchers assessed the effectiveness of metformin for the treatment of polycystic ovary syndrome (PCOS)-related acne by searching PubMed, the Cochrane Library, and Embase databases for human clinical studies in any language on November 23, 2019. The keywords involved ‘acne’ and ‘polycystic ovary syndrome’ combined with ‘metformin,’ ‘biguanide,’ or ‘glucophage. Fifty-one studies on 2,405 PCOS patients were included. Metformin as stand-alone or adjuvant treatment was associated with acne improvement in PCOS patients. To confirm these outcomes, more randomized controlled trials are required.