Safety and efficacy of topical metformin 30% cream versus triple combination cream (Kligman's formula) in treating melasma: A randomized controlled study

Melasma is an acquired common pigmentary condition that mostly presents as pigmented macules on the face. Triple combination creams (TCC), commonly known as kligman's formula, had been regarded as the mainstay of treatment for years. Topical metformin was recently studied for its melanopenic effects and potential use in melasma.This study aimed to evaluate the efficacy and safety of using 30% metformin cream to that of triple combination creams (Kligman's formula) in treating melasma.About 40 patients complaining of melasma were recruited for this controlled randomized trial and were divided into 2 groups. Group 1 (n = 20) subjects received 30% metformin cream whereas group 2 (n = 20) were treated with TCC for eight consecutive weeks. Pigmentation severity and improvements were assessed using the melasma area severity index (MASI) at baseline and after 8 weeks of using treatment.MASI score decreased dramatically from 12.18 ± 9.33 before treatment to 5.59 ± 4.61 at Week 8 with a mean decrease percentage of 55.97 ± 16.77 for group 1 (p = 0.001) and from 16.05 ± 8.73 to 7.54 ± 5.77 with a mean decrease percentage of 56.50 ± 19.44 for group 2 (p = 0.001). No significant difference was reported between the two treatment modalities regarding the reduction in melasma throughout the study period (p = 0.968).Metformin cream is a safe, potential effective treatment for melasma, which needs to be verified by long-term large scale studies in diffident populations.