PT-141

Melanocortin-receptor agonist · cyclic heptapeptide

Identifier graph

Cross-references to canonical chemistry knowledge graphs. Each binding is the same identity used in PubMed-indexed literature.

CAS Registry Number
32780-32-8 · CAS Common Chemistry
InChIKey
GSQYAWMREAXBHF-UOYQFSTFSA-N
PubChem CID
CID 446685
Wikidata
Q27113564
ChEMBL
CHEMBL2070241
Molecular formula
C50H68N14O10
Molecular weight
1025.18 g/mol
Peptide sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
IUPAC name
(1R,2S,3S,4S,6R)-4-amino-6-(hydroxymethyl)cyclohexane-1,2,3-triol

What is PT-141?

PT-141, also known as Bremelanotide, is a cyclic heptapeptide melanocortin receptor agonist with the structure Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It is structurally related to Melanotan-II — both are synthetic analogues of the natural melanocortin α-MSH — but differs in its C-terminal carboxylic acid (PT-141) versus C-terminal amide (Melanotan-II).

Bremelanotide is FDA-approved as Vyleesi® in the United States for the treatment of acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women. It is not currently MHRA-licensed in the United Kingdom.

CAS 32780-32-8, molecular formula C₅₀H₆₈N₁₄O₁₀, molecular weight 1025.18 g/mol. Wikidata QID Q27113564, PubChem CID 446685, ChEMBL ID CHEMBL2070241.

Mechanism of action

PT-141 activates melanocortin receptors, principally the melanocortin-4 receptor (MC4R) in the central nervous system. Unlike the closely-related Melanotan-II, which also activates MC1R (driving pigmentation), PT-141 has a stronger MC4R selectivity profile and a corresponding behavioural-effect profile dominated by central nervous system effects rather than pigmentation.

The clinical indication (HSDD) reflects MC4R activation in the hypothalamus, which modulates dopaminergic pathways involved in sexual desire.

Research context

Investigated in preclinical and clinical studies of central melanocortin signalling, sexual-behaviour pharmacology, and appetite regulation (MC4R activation has anorectic effects). Researchers commonly compare PT-141 to Melanotan-II in receptor-selectivity head-to-head studies.

Analytical specifications

Every batch of PT-141 supplied by NMChem is characterised by reversed-phase HPLC for purity determination and by mass spectrometry for identity confirmation. Certificate of Analysis (COA) documents are issued per batch and made available on request.

Identity is confirmed by electrospray-ionisation mass spectrometry (ESI-MS); the observed mass falls within ±2 Da of the theoretical monoisotopic mass calculated from the residue sequence. Purity is determined by reversed-phase HPLC on a C18 column with a trifluoroacetic-acid-modified water/acetonitrile gradient and reported as the area-under-curve percentage of the main peak at 214 nm. NMChem specification is ≥99% main peak. Material ships as lyophilised powder and must be reconstituted in sterile water or bacteriostatic water immediately before use.

Browse the COA database

UK regulatory status

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.

Research literature

Selected peer-reviewed publications from PubMed referencing this compound.

  1. PT-141 Palatin. Hedlund P et al. · Current opinion in investigational drugs (London, England : 2000) · 2004
    PubMed PMID 15134289
  2. Medical Treatment of Female Sexual Dysfunction. Nappi RE et al. · The Urologic clinics of North America · 2022
    PubMed PMID 35428435

Related compounds

Other research compounds in adjacent mechanism classes or commonly used alongside PT-141.

  • Melanotan-II
    Melanocortin-receptor agonist · cyclic heptapeptide
  • KPV
    α-MSH C-terminal tripeptide

Frequently asked questions about PT-141

Is PT-141 the same as Bremelanotide?
Yes — Bremelanotide is the International Nonproprietary Name (INN) for PT-141. The molecule is FDA-approved as Vyleesi® in the United States for HSDD in premenopausal women. It is not currently MHRA-licensed in the UK.
How is PT-141 different from Melanotan-II?
Both are cyclic heptapeptide melanocortin agonists derived from α-MSH. PT-141 has a C-terminal carboxylic acid; Melanotan-II has a C-terminal amide. PT-141 is more selective for MC4R (central effects) and weaker at MC1R (pigmentation). Melanotan-II is a more balanced multi-receptor agonist with stronger MC1R activity.

Get research-grade PT-141 from NMChem

UK supplier · HPLC and MS verified · Per-batch Certificate of Analysis · Tracked Royal Mail dispatch.

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