What Is PT-141? Research Guide
Definition
PT-141 (bremelanotide) is a cyclic seven-residue melanocortin receptor agonist, Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH, with CAS number 189691-06-3, formula C50H68N14O10 and an average molecular weight of 1025.2 Da. It is the free-acid metabolite of melanotan II and is studied in melanocortin receptor and neuroendocrine signaling research.
Key Takeaways
- →PT-141 (bremelanotide) is a cyclic seven-residue melanocortin receptor agonist, Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH, with CAS number 189691-06-3, formula C50H68N14O10 and an average molecular weight of 1025.2 Da. It is the free-acid metabolite of melanotan II and is studied in melanocortin receptor and neuroendocrine signaling research..
- →Available for in-vitro research at ≥99% HPLC-verified purity from Peptide.Express.
- →Certificate of Analysis included with every order. Same-day US shipping.
PT-141 Specifications
| Property | Value |
|---|---|
| Compound | PT-141 |
| CAS Number | 189691-06-3 |
| Molecular Formula | C50H68N14O10 |
| Molecular Weight | 1025.2 Da |
| Sequence / Structure | Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH (melanocortin agonist) |
| Mechanism Class | Melanocortin receptor agonist |
| Purity | ≥99% by HPLC, batch-specific CoA included |
Registry records for PT-141: PubChem
PT-141 Mechanism of Action
PT-141 is an agonist across the melanocortin receptor family, with hypothalamic MC4R and MC3R the subtypes of research interest and Gs/cAMP the transduction route. One structural change separates it from melanotan II: the C-terminal amide is replaced by a free carboxylic acid, which is what hydrolysis of melanotan II produces, and it shifts receptor preference away from the MC1R-driven melanogenesis that dominates melanotan II pharmacology. The pharmacologically important point is the site of action rather than the potency — melanocortin agonism here is central, not vascular, which is why this class is studied on an entirely different axis from PDE5 inhibitors.
PT-141 Research Applications
MC3R and MC4R receptor pharmacology, resolving subtype selectivity through cAMP accumulation in cells expressing individual melanocortin receptors.
Central neuroendocrine signaling models, where the hypothalamic rather than peripheral site of action is the property under test.
Structure-activity comparison with melanotan II, in which an amide-to-acid change at a single terminus produces a measurable shift in subtype preference.
Cyclic peptide chemistry, since the Asp-Lys lactam bridge is a standard method of locking a peptide into its active conformation and blocking exopeptidases.
PT-141 Storage Requirements
Store lyophilized PT-141 at -20°C (-4°F) and protect it from light: the tryptophan residue is photo-oxidizable, so an amber or foil-wrapped vial is the correct default rather than an optional precaution. Reconstituted, keep at 2-8°C (36-46°F) and use within 30 days. The lactam bridge makes the cyclic core resistant to exopeptidases, so oxidation rather than proteolysis is the degradation route to expect in solution.
PT-141 at Peptide.Express
All PT-141 sold by Peptide.Express is HPLC-verified at ≥99% purity with a Certificate of Analysis included. Same-day US shipping on orders before 2 PM EST. For in-vitro laboratory research use only.
View PT-141 Product DetailsFrequently Asked Questions
What is PT-141 (Bremelanotide)?
PT-141, generic name bremelanotide, is a cyclic seven-residue melanocortin receptor agonist with CAS number 189691-06-3, molecular formula C50H68N14O10 and an average molecular weight of 1025.2 Da. It is the free-acid metabolite of melanotan II and is studied in MC3R/MC4R receptor pharmacology and central neuroendocrine signaling.
What is the difference between PT-141 and Melanotan II?
One functional group at the C-terminus. Melanotan II ends in an amide (C50H69N15O9, 1024.2 Da); PT-141 ends in a free carboxylic acid (C50H68N14O10, 1025.2 Da) and is the product of hydrolyzing that amide. Melanotan II is the stronger MC1R agonist and drives melanogenesis, while PT-141 is studied chiefly for MC3R and MC4R activity.
Is PT-141 FDA approved?
Bremelanotide is approved by the FDA as Vyleesi, an injectable product for acquired, generalized hypoactive sexual desire disorder in premenopausal women. The approval covers that finished product. Research-grade bremelanotide powder is not a medicine, has not been evaluated as one, and is supplied for in-vitro laboratory research only.
What is the structure of PT-141?
PT-141 is Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH: an N-acetylated norleucine followed by a six-residue ring closed by a lactam bond between the aspartate and lysine side chains. Norleucine and D-phenylalanine are both non-standard residues, and the ring constrains the peptide into its receptor-active conformation.
Where can I buy PT-141 for research?
Research-grade PT-141 is available from Peptide.Express at ≥99% HPLC-verified purity with a Certificate of Analysis included. Visit peptide.express/catalog/pt-141 for full specifications.
References
- Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003. Read Molinoff et al. on PT-141 as an MC3R/MC4R melanocortin agonist
- Mountjoy KG, Mortrud MT, Low MJ, Simerly RB, Cone RD. Localization of the melanocortin-4 receptor (MC4-R) in neuroendocrine and autonomic control circuits in the brain. Mol Endocrinol. 1994. Read Mountjoy et al. on MC4R distribution in hypothalamic and autonomic circuits
- Vyleesi (bremelanotide) injection, FDA-approved prescribing information via DailyMed. Bremelanotide is approved for hypoactive sexual desire disorder in premenopausal women; the approval covers the finished drug product only. Read the Vyleesi (bremelanotide) FDA prescribing information
Research Areas Using PT-141
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