Background: Acne vulgaris (AV) is a common chronic skin condition affecting millions of people around the globe. Its main target is the pilosebaceous unit, and this condition has different etiological factors with a complex interaction. Several treatments, either topical or systemic, are used in acne treatment. Metformin is an oral hypoglycemic drug, but it was found to be beneficial in chronic inflammatory skin conditions. This research aimed to evaluate the efficacy of oral metformin as an adjuvant to topical adapalene gel in treatment of female patients with AV.

Methods: Thirty females suffering from mild to moderate AV were included in clinical trial, managed using oral metformin (500 mg twice daily), along with nightly topical applications of adapalene gel for 12 weeks. The clinical outcomes were assessed using the rotal Lesion Count (TLC), the Global Acne Grading System (GAGS), as well as the Dermatology Life Quality Index (DLQI) to evaluate both the severity of acne in addition to its impact on the patients' quality of life.

Results: We found a significant reduction in GAGS (P = 0.001) and TLC (P = 0.001) after the treatment between the 2 groups. Regarding the therapeutic response according to TLC reduction, 11 patients (36.7%) showed marked improvement, 16 patients (53.3%) showed moderate improvement, and 3 patients (10%) showed mild improvement. A significant reduction of DLQI was also seen after treatment (P = 0.001).

Conclusion: Oral metformin could be a safe and effective adjuvant to topical adapalene in the treatment of AV with minimal side effects.