Inhibitory Effect of 505 nm Green Light Emitting Diode on Melanin Synthesis in Cellular Experiments and a Human Intervention Study

Light-emitting diodes (LEDs) are currently gaining attention in aesthetic medicine for their applications in the treatment of pigmentation and wrinkles. While several wavelengths of LEDs have been reported to inhibit melanin production by targeting melanin synthesis-related enzymes, melanosomes, and paracrine factors stimulating melanogenesis from keratinocytes, the effects of green LED (GLED) remain largely unexplored. This study aimed to investigate the effects of GLED on cell viability, melanin production, and melanin-related gene expression using B16 melanoma cells and 3-dimensional (3D) skin models. Furthermore, its efficacy in improving skin pigmentation was evaluated through a human intervention study with GLED-equipped facial masks. The melanin synthesis inhibitory effects of 505 nm GLED were evaluated using B16 mouse melanoma cells, a 3D skin model containing melanocytes, and a human intervention study with 505 nm GLED-equipped masks. 505 nm GLED irradiation reduced melanin production in melanogenesis-induced B16 mouse melanoma cells by suppressing the gene expression levels of microphthalmia-associated transcription factor and tyrosinase. Furthermore, GLED irradiation also reduced melanin content in 3D skin models without affecting cell viability. Finally, a human intervention study demonstrated that GLED irradiation on human facial skin effectively decrease pigmentation. These findings suggest 505 nm GLED is a potential depigmentation strategy.