MC1R and the melanin switch

How afamelanotide turns on the skin's pigment machinery

Afamelanotide works mainly through one receptor, MC1R, which its label says it binds predominantly, triggering a chemical relay that ends in pigment. This unit follows that relay from the receptor on a melanocyte down to the genes that build eumelanin.

It also covers the quieter half of the story: MC1R signaling may protect skin in ways that do not depend on pigment at all, a claim that rests here on a mouse model rather than on human data.