HOME / RESEARCH COMPOUNDS / PT-141
Lyophilised vial · supplied for laboratory research
PT-141 is the development name for bremelanotide, a synthetic cyclic heptapeptide developed by Palatin Technologies as an analogue of α-melanocyte-stimulating hormone (α-MSH). A lactam bridge between aspartic acid and lysine closes the ring: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It activates several melanocortin receptors.
Bremelanotide is FDA-approved in the US as the medicine Vyleesi, for one narrow indication. The PT-141 sold here is not Vyleesi: it is a lyophilised powder in a sealed 10 mg vial, supplied for laboratory research only and not for human or veterinary use. The summary below covers the pharmacology, the trial program and the compound's regulatory status.
| Compound class | Synthetic cyclic heptapeptide; melanocortin receptor agonist (α-MSH analogue) |
|---|---|
| Sequence | Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH |
| Sequence (one-letter) | Ac-Nle-c[DHfRWK]-OH (norleucine has no standard one-letter code; f = D-phenylalanine) |
| Molecular formula | C50H68N14O10 (free base, PubChem and FDA label) |
| Molar mass | 1025.2 g/mol (free base, PubChem) |
| CAS number | 189691-06-3 (free base); 1607799-13-2 (acetate) |
| PubChem CID | 9941379 |
| Other names | Bremelanotide, PT 141 |
| Supplied as | Lyophilised powder, sealed vial |
| Strength | 10 mg per vial |
| Storage (lyophilised) | Sealed, dry and dark at −20 °C or colder; −50 to −80 °C for long-term storage |
| Intended use | Laboratory research only |
The receptor pharmacology is set out in the Vyleesi prescribing information. Bremelanotide non-selectively activates several melanocortin receptor subtypes, in the order of potency MC1R, MC4R, MC3R, MC5R, MC2R, and the label identifies binding at MC1R and MC4R as the most relevant. MC4R is expressed on neurons in many areas of the central nervous system, and MC1R on melanocytes, which is the basis of the label's pigmentation warning. The label states that the mechanism in hypoactive sexual desire disorder (HSDD) is unknown.1
PT-141 shares its cyclic seven-residue sequence with melanotan II, which ends in an amide rather than a free acid. The PT-141 (bremelanotide) research overview covers that relationship and the early studies in men, and how HPLC and mass spectrometry test peptide identity explains why a 1 g/mol difference needs high-resolution methods.
The US FDA approved bremelanotide as Vyleesi on 21 June 2019 (NDA 210557)5 for premenopausal women with acquired, generalised HSDD only; the label states it is not indicated for postmenopausal women, for men or to enhance sexual performance.1 That approval attaches to a specific finished product and does not by itself make bremelanotide an approved medicine in Australia. Bremelanotide is not named in the Poisons Standard June 2026 (F2026L00633).6 It does not appear by name in the 2026 WADA Prohibited List either; because the List's sections give examples rather than complete catalogues, not being named is not the same as being permitted.7
Research-grade PT-141 is a laboratory chemical, not an approved medicine. See research peptides and Australian law.
Keep the sealed vial dry, dark and frozen at −20 °C or colder (−50 to −80 °C for long-term storage), and let it reach room temperature in a desiccator before opening. PT-141 contains a tryptophan residue, one of the residues the storage literature flags for air oxidation and photo-oxidation, so limit its exposure to light and air. Solutions should be kept only briefly: split a reconstituted stock into single-use aliquots, freeze them and do not refreeze thawed material. See how to store peptides and reconstituting peptides with bacteriostatic or sterile water for the reasoning behind each step.
No. PT-141 and bremelanotide name the same cyclic heptapeptide, but Vyleesi is a specific FDA-approved finished product: a sterile solution with defined excipients, made and labelled under an approved US application. A lyophilised PT-141 powder sold for laboratory research is none of those things and carries none of that approval.
The CAS number for bremelanotide free base is 189691-06-3, and the acetate salt has its own number, 1607799-13-2. PubChem (CID 9941379) lists the free base as C50H68N14O10 with a molar mass of 1025.2 g/mol, matching the FDA label, so the salt form matters when comparing a formula or mass against a record.
No, although the two are closely related. They share the same cyclic seven-residue sequence, but melanotan II ends in a C-terminal amide and bremelanotide in a free carboxylic acid, a mass difference of about 1 g/mol. Low-resolution mass measurements can miss that gap, so identity work calls for high-resolution mass spectrometry or chromatography against a reference standard.
Bremelanotide is not named in the June 2026 Poisons Standard. Its US approval as Vyleesi covers that specific product and does not by itself make bremelanotide an approved medicine in Australia. Research-grade PT-141 is supplied for laboratory research only; our guide to research peptides and Australian law sets out how the TGA treats unapproved peptide products.
PT-141 is the development name for bremelanotide. This overview covers its structure and receptor pharmacology, the clinical trials, exactly what the FDA approved as Vyleesi, and why a research compound is not that medicine.
All products are supplied strictly for laboratory research and in-vitro applications. They are not approved therapeutic goods in Australia and are not for human or veterinary use.
