PT-141 and Melanotan II compared: chemistry, targets and regulatory records
PT-141 and melanotan II are cyclic heptapeptide melanocortin receptor agonists with the same lactam-bridged core. They differ at the C-terminus: PT-141 ends in a free acid and melanotan II in an amide.
Research-use information. This page summarises published literature and regulator records. It is not guidance for use, not medical advice, and not a statement that any material is suitable for use in people or animals.
How do PT-141 and Melanotan II differ on the facts?
| Fact | PT-141 | Melanotan II |
|---|---|---|
| Class | Cyclic heptapeptide melanocortin receptor agonist | Cyclic heptapeptide, alpha-MSH analogue |
| Length | 7 residues | 7 residues |
| Molecular formula | C50H68N14O10 | C50H69N15O9 |
| Average molecular weight | 1025.2 g/mol | 1024.2 g/mol |
| Receptor or pathway background | Melanocortin receptors | Melanocortin receptors |
| FDA (Drugs@FDA) | 1 application listed (Prescription) | No application listed |
| EMA (centrally authorised) | No centrally authorised medicine listed | No centrally authorised medicine listed |
| MHRA (Products) | No product document found | No product document found |
| WADA 2026 list | Not named | Not named |
| Studies in our library | 4 | 3 |
| PubMed records for the search terms | 114 | 624 |
| Registered studies (ClinicalTrials.gov) | 10 | 1 |
Data dates: chemistry checked against PubChem 2026-10-05; regulatory records 2026-10-05; WADA list 2026-10-05; PubMed counts 2026-10-05.
What do the cited papers say differs between PT-141 and Melanotan II?
- The catalog sequences are Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH for PT-141 and the same ring with a C-terminal amide for melanotan II; their PubChem formulas are C50H68N14O10 and C50H69N15O9.
- Cryo-EM structures of the human MC4R include bremelanotide (PT-141) as a bound ligand; a medicinal-chemistry paper describes melanotan II as a potent and unselective agonist of human melanocortin receptors.[2],[1]
- Their records in the FDA, EMA and MHRA databases differ; see the table.
Nothing on this page ranks one compound above the other or states what either does for a person.
Which studies are cited on this page?
[1] Tomassi S, Dimmito MP, Cai M, D'Aniello A, Del Bene A, Messere A, et al.. CLIPSing Melanotan-II to Discover Multiple Functionally Selective hMCR Agonists. J Med Chem. 2022;65:4007-4017.
Replaced the lactam cyclisation of melanotan II with scaffold chemistry and profiled functional selectivity at human melanocortin receptors.
[2] Zhang H, Chen LN, Yang D, Mao C, Shen Q, Feng W, et al.. Structural insights into ligand recognition and activation of the melanocortin-4 receptor. Cell Res. 2021;31:1163-1175.
Cryo-EM structures of full-length human MC4R bound to alpha-MSH, afamelanotide, bremelanotide and a small-molecule ligand.