Patients and methods: This split face study was designed to evaluate the efficacy and safety of 12 weeks application of daily topical metformin in comparison to placebo in the treatment of 21 adolescent female patients suffering from acne vulgaris.Patients were assessed and lesions (comedones, papules, pustules and nodules) were counted at weeks 0,4,8,12,16Week 12 (end of the treatment): the number of comedones, papules and nodules (but not pustules) decreased significantly on the metformin side compared to the placebo side

Acne vulgaris (AV), a widely common disorder, that negatively affects the quality of life. Metformin is a relatively safe, cheap and well tolerated drug that is widely used in the treatment of Diabetes. Systemic metformin has demonstrated promising results in treating acne, while topically it was studied for melasma and recalcitrant central centrifugal cicatricial alopecia. To study the safety and efficacy of topical metformin 30% in the treatment of AV. Twenty‐seven female AV patients were asked to blindly apply metformin and placebo gels to either side of the face for 12 weeks. AV lesion count was performed at baseline, at each visit and 4 weeks after end of treatment. At the end of the treatment period, the treated side showed significant improvement of comedones, papules and nodules but not pustules. Although, lesions count increased 1 month after stopping treatment, comedones and papules numbers were still significantly less on the metformin side compared to placebo. No side effects were reported. The limited number of patients studied and the limited follow‐up period. The metformin effect was not studied on cellular and molecular levels. Topical metformin nanoemulsion gel can be a promising safe and effective treatment of AV.