A non-selective melanocortin receptor agonist developed at the University of Arizona. Research applications span skin pigmentation, sexual dysfunction, and appetite regulation — with a complex regulatory history and significant safety considerations.
Mechanism of Action
Melanotan II is a cyclic analogue of alpha-melanocyte-stimulating hormone (α-MSH). It binds with high affinity to melanocortin receptors (MCRs), which are G protein-coupled receptors distributed throughout the skin, brain, and peripheral tissues.
Melanocortin Receptor Binding Profile
MT-II is non-selective — it binds all five melanocortin receptor subtypes (MC1R–MC5R). This broad activity is the source of both its research utility (pigmentation, sexual function, appetite) and its side effect profile (nausea, flushing, spontaneous erection).
Research History
University of Arizona researchers began developing synthetic melanocortin analogues after α-MSH was identified as the endogenous peptide responsible for skin pigmentation. The goal was a 'tanning pill' — the sexual function effects were discovered incidentally in early human trials.