PGR and freckles: Similarly, a cross-sectional study conducted in Indonesia revealed a melasma prevalence of 91.7% among 36 women taking oral contraceptives, demonstrating a positive correlation between incidence and usage duration.45 Elevated expression of oestrogen receptors (ER) and progesterone receptors (PR) has been consistently observed in melasma-affected dermal tissues at the molecular level.46-48 Upon binding to ERs, oestrogen activates rate-limiting tyrosinase in melanogenesis, thereby enhancing synthesis of melanin.