PT-141, also known by the name bremelanotide, is a synthetic cyclic heptapeptide studied as an agonist of melanocortin receptors. It is a structural analogue of alpha-melanocyte-stimulating hormone (alpha-MSH) and a metabolite of the earlier research compound Melanotan II, from which it differs by the absence of the C-terminal amide. Its research profile centers on the melanocortin receptor family — a group of five G-protein-coupled receptors involved in a wide range of signalling pathways — and particularly on the MC3R and MC4R subtypes.
Research background
The melanocortin system has been an active area of receptor pharmacology for three decades, and PT-141 appears in that literature as a probe compound for characterizing MC3R/MC4R-mediated signalling. Its cyclic structure — the ring closed between a glutamic acid and a lysine residue — distinguishes it from linear alpha-MSH analogues and contributes to its receptor-binding characteristics, which is what makes it useful as a comparison compound in receptor-selectivity studies.
Structure and analytical profile
PT-141 is a cyclic peptide of seven amino acids (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH) with a molecular weight of approximately 1025.2 g/mol. The cyclic structure and the D-phenylalanine substitution are the analytically distinctive features: mass spectrometry establishes identity against the expected mass, and chromatographic purity analysis resolves the compound from linear or ring-opened impurities, which are the degradation products a certificate should be able to exclude.
Verifying a lot
The standard three checks apply: the lot number on the certificate matches the vial, the issuing laboratory is named with the original report attached, and the report verifies with the laboratory directly. Every PT-141 lot we sell publishes its certificate in the certificate archive, searchable by product and lot number.
Handling notes
Supplied lyophilized; store cool, dark and dry until laboratory use. Standard research practice reconstitutes with bacteriostatic water. All handling is for qualified laboratory settings by qualified personnel.
Frequently asked research questions
Are PT-141 and bremelanotide the same thing? Yes — bremelanotide is the nonproprietary name for the same molecule. Research catalogs use PT-141; the literature uses both.
How does PT-141 relate to Melanotan II? PT-141 is a metabolite of Melanotan II lacking the C-terminal amide group. They are distinct molecules with distinct masses, and a certificate should identify which one is in the vial.
What should a PT-141 certificate show? Identity by mass spectrometry consistent with ~1025 g/mol, chromatographic purity, the lot number, the issuing laboratory, and a report date. A certificate missing any of those is incomplete.
All products discussed are for laboratory research use only and are not for human or veterinary consumption. Nothing here describes or endorses any use in humans or animals.