DNA Methyltransferases in Malar Melasma and Their Modification by Sunscreen with 4% Niacinamide, 0.05% Retinoic Acid, or Placebo

This study examined the impact of sunscreen combined with 4% niacinamide, 0.05% retinoic acid, or placebo on DNA methyltransferases (DNMTs) in 30 female patients with malar melasma over 8 weeks. All treatment groups showed clinical improvement, with the niacinamide group achieving the most significant reduction in Melasma Activity and Severity Index (MASI) scores and colorimetric values. Both niacinamide and retinoic acid treatments significantly reduced DNMT1 expression and fluorescence in melasma lesions, suggesting a decrease in DNA methylation and improved melasma symptoms. The study highlighted the potential of these treatments to reduce hyperpigmentation by altering DNA methylation, though it noted limitations such as the small sample size and focus on malar melasma. Further research was recommended to explore the underlying methylation mechanisms and other epigenetic factors in melasma.