Sunlight Continues to Damage Skin in the Dark: Yale News
Much of the damage that ultraviolet radiation (UV) does to skin occurs hours after sun exposure. In the past, experts believed that melanin protected the skin by blocking harmful UV light. But there was also evidence from this study suggesting that melanin is associated with skin cell damage.
Sanjay Premi, associate research scientist in the Brash laboratory, discovered that the UV light activated two enzymes that combined to “excite” an electron in melanin. The energy generated from this process —known as chemiexcitation — was transferred to DNA in the dark, creating the same DNA damage that sunlight caused in daytime.