Melanotan-II

Melanotan II is a synthetic cyclic lactam analog of alpha-melanocyte stimulating hormone (α-MSH) that binds to melanocortin receptors, primarily MC1R in skin and MC4R in the brain. The peptide induces melanogenesis, stimulating melanocytes to produce eumelanin and resulting in skin pigmentation (tanning) without UV exposure. Beyond tanning effects, Melanotan II acts on hypothalamic MC4R to suppress appetite and may promote fat loss. Research indicates effects on sexual arousal and erectile function through central nervous system pathways, leading to development of the related compound PT-141 (Bremelanotide). Common side effects include nausea, facial flushing, and fatigue. The peptide requires subcutaneous injection and users typically undergo a loading phase followed by maintenance dosing. Melanotan II is not FDA-approved and carries risks including potential effects on existing moles and unknown long-term safety. It should be distinguished from Melanotan I (Afamelanotide), which is more selective for MC1R and has been approved in some countries for specific photosensitivity disorders.