Oral Metformin for Treating Melasma in Latin American Women

Participants received oral metformin tablets for the treatment of melasma. The initial dose was 500 mg once daily for four weeks. At week 4, participants who tolerated the medication well increased their dose to 500 mg twice daily for the remaining eight weeks of the study. Participants were instructed to avoid other melasma treatments during the trial and to use sunscreen (SPF 30 or higher) daily.