Comparing the Efficacy of Topical Metformin and Placebo in the Treatment of Melasma: A Randomized, Double-blind, Clinical Trial

Introduction: Generally affecting women, melasma is the acquired disorder of hyperpigmentation, and researches are still ongoing to find an effective, fast, and low-side-effect drug treating this disease. The present study is aimed at comparing the efficacy of topical metformin and placebo in the treatment of melasma. Methods: Sixty patients with melasma were treated in placebo and topical metformin recipient groups in a double-blind clinical trial. In addition to the demographic and laboratory findings of patients before and after the intervention, the MASI Score of patients in weeks 0, 4, 8, and 12 of the study and then one month after the study were analyzed using SPSS version 20 software. Results: The mean age of the studied patients was 35.25 +/- 7.11 years. No significant difference was observed between the phenotypes (P= .49) and the type of melasma (P= .63) in the two groups. The mean MASI score of patients at the time of being included in the study in the placebo group was 10.47 +/- 3.08; and in the metformin group, it was 11.93 +/- 4.64 (P = .16). Compared to the beginning of the study, the MASI scores were significantly decreased in both groups of placebo (P = .00) and metformin (P = .00) one month after the end of the study; nevertheless, no statistically significant difference was observed between the MASI Scores of two groups in any of the study periods (P> .05). Conclusion: The results of the present study showed that metformin cream significantly declines the patients' MASI score and does not have any effect on patients' laboratory markers. Of course, no significant difference was observed between the MASI scores of the patients receiving metformin and the placebo group; however, the MASI score decrease trend continued until the 12th week; while in the placebo group, no significant decrease was seen after eight weeks.