What is Melanotan-2?
Melanotan-2 sits in the melanocortin family, the ligand class derived from proopiomelanocortin. Our molecular records list CAS 121062-08-6, formula C50H69N15O9 and an average molecular weight of 1024.18, filed under the synonyms MT-2 and cyclic alpha-MSH analogue. No residue-by-residue sequence is carried for this entry, so none is written out here.
Two points follow from that formula. It contains no sulfur, so methionine and cysteine oxidation, usually the first concern in peptide stability planning, is not the leading degradation route. The cyclic architecture named in the synonym is what the literature credits with slowing exopeptidase trimming relative to the linear parent hormone.
Published work uses the compound as a broadly acting agonist across MC1R, MC3R, MC4R and MC5R rather than as a subtype-selective tool. Cell assays employ it as a reference agonist for cyclic AMP accumulation, and rodent studies have used it to model pigmentation responses and central control of feeding behaviour. The potency ordering across the four subtypes is not settled, and animal pharmacokinetics remain thinly described.
Reconstitution & handling
Bacteriostatic water is the usual diluent for a vial drawn from more than once, sterile water for a single working solution. Run the stream down the inside wall rather than onto the cake, then swirl gently until clear, since shaking causes foaming and interfacial denaturation. Concentration is mass over volume arithmetic, and the net peptide content figure from the certificate should be applied when an exact molar value matters.
Storage & stability
Hold the sealed lyophilized vial at -20 °C, desiccated and protected from light, which is the stable form for long storage. After reconstitution keep it at 2 to 8 °C and split it into single-use aliquots, because repeated freeze-thaw is harder on dilute melanocortin analogues than refrigerated standing. Amber glass or foil is standard for this class, whose aromatic side chains are photolabile.
How it's tested
Each lot is run by reversed-phase HPLC with ultraviolet detection at 214 and 220 nm against a 99 percent or better main-peak threshold. Identity is confirmed by electrospray mass spectrometry against the theoretical average mass of 1024.18 in our molecular records. Net peptide content and water content are reported separately from chromatographic purity, and a lot-matched certificate of analysis is available on request.