Insight Into the Cellular Activities of Tranexamic Acid as an Option for Melasma Treatment.

Melasma and other hyperpigmentation disorders represent a significant challenge in dermatology. Tranexamic acid (TXA), traditionally known for its antifibrinolytic activity via inhibition of plasminogen activation, has recently emerged as a promising depigmenting agent. However, its cellular effects on skin cells involved in melanogenesis remain poorly understood. In this study, we investigated TXA's impact on melanocytes, keratinocytes, and inflammatory cells. TXA directly inhibited melanin synthesis in B16 melanoma cells, with an additive effect when combined with α-arbutin. In keratinocytes and macrophages, TXA attenuated inflammatory responses triggered by the plasminogen/plasmin (Plg/Plm) pathway. Moreover, TXA reduced lipopolysaccharide-induced pro-inflammatory gene expression in mouse macrophages, suggesting interference with Toll-like receptor-mediated inflammation. These findings highlight TXA's multifaceted actions on skin cells involved in pigmentation and support its therapeutic potential in melasma and potentially other skin diseases.