Melanocortin receptor agonists
Melanocortin receptor agonists copy alpha-MSH, a hormone that darkens skin pigment, reduces inflammation, and in the brain affects appetite and sexual arousal. Afamelanotide is an approved implant that reduces painful light reactions in erythropoietic protoporphyria, while melanotan II is an unapproved injectable sold for tanning. Darkened skin, new or darker moles, nausea, flushing, and headache are the most common effects. The key safety point is skin surveillance, because darker moles can hide a melanoma, and unapproved products add the risks of unknown dose and purity.