Melanotan-II

Melanotan-II (MT-II, MT2) is a cyclic heptapeptide melanocortin receptor agonist with the structure Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ — structurally identical to PT-141 (Bremelanotide) except for the C-terminal amide where PT-141 has a free carboxylic acid. The compound was originally developed in the 1980s as a research probe for the melanocortin system.

CAS 121062-08-6, molecular formula C₅₀H₆₉N₁₅O₉, molecular weight 1024.18 g/mol. Wikidata QID Q423855, PubChem CID 92432, ChEMBL ID CHEMBL3735690.

Melanotan-II is a broad-spectrum melanocortin agonist with activity at MC1R (pigmentation), MC3R, MC4R (central appetite and sexual behaviour) and MC5R. The compound's structural cyclisation (the Asp-Lys lactam bridge) confers protease resistance and conformational restriction that enables potent, long-acting agonism across the receptor family.

The MC1R activity drives the pigmentation effect (increased melanogenesis in melanocytes) for which Melanotan-II is most commonly characterised in laboratory research.

Investigated in preclinical studies of melanocortin receptor pharmacology, melanocyte biology, and central appetite/sexual-behaviour signalling. Melanotan-II is also used as a tool compound in receptor-selectivity experiments because of its broad receptor-family agonism.

Supplied as a research-grade reference standard for laboratory use only. Not a licensed medicinal product in the United Kingdom and not approved by the MHRA for human or veterinary administration. Sale is restricted to researchers, institutions and laboratory professionals; the compound must be retained within research premises. End-user compliance with the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 (where applicable) and local institutional biosafety policy is the responsibility of the buyer.