---
title: "PT-141 research summary and literature | Sable Peptides"
description: "PT-141: what the published literature covers, how it compares with Melanotan II, key facts (CAS 189691-06-3, MW 1025.2) and 2 verified PubMed citations."
canonical: https://www.sablepeptides.co.uk/research/pt-141
dateModified: 2026-10-14
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

[Research summaries](/research)

# PT-141: research summary

For laboratory research use only. Not for human or veterinary use. This page summarises published literature. It gives no advice on use.

## What the literature covers

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide that agonises melanocortin receptors. It is a metabolite-related analogue of Melanotan II: the C-terminal amide is replaced with a free carboxylic acid.

Analytical literature describes how to characterise it. LC-HRMS/MS has been used to profile bremelanotide acetate and its degradation products, including epimerisation, and UHPLC-MS/MS methods quantify it at very low concentrations.

PT-141 has a molecular weight of about 1025.2 g/mol (C50H68N14O10). The cyclic lactam bridge and its D-amino acid make degradant and epimer checks relevant to quality control.

## Key facts

|  | PT-141 | Melanotan II |
| --- | --- | --- |
| CAS | 189691-06-3 | 121062-08-6 |
| Formula | C50H68N14O10 | C50H69N15O9 |
| Molecular weight (g/mol) | 1025.2 | 1024.2 |

Source: [PubChem CID 9941379](https://pubchem.ncbi.nlm.nih.gov/compound/9941379).

## PT-141 compared with Melanotan II

PT-141 and Melanotan II are closely related cyclic melanocortin peptides that differ at the C-terminus: PT-141 ends in a free acid, Melanotan II in an amide. Their masses differ by about 1 Da, so the CoA needs high-resolution mass spectrometry to tell them apart.

[Full side-by-side: PT-141 vs Melanotan II](/versus/melanotan-2/pt-141)

## Frequently asked questions

What is the generic name of PT-141?

Bremelanotide.

How does PT-141 differ from Melanotan II?

PT-141 has a C-terminal carboxylic acid where Melanotan II has an amide. Otherwise the cyclic structures are closely related.

What analytical methods are published for PT-141?

LC-HRMS/MS degradant profiling and UHPLC-MS/MS quantification are both in the peer-reviewed literature.

## Published literature cited

1.  Yuvaraaj VK, Sharma N. (2026). Comprehensive characterization of bremelanotide acetate and its degradants by LC-HRMS/MS and predicting epimerization through computational modelling. *Anal Methods*. [PMID 42485063](https://pubmed.ncbi.nlm.nih.gov/42485063/) · [doi:10.1039/d6ay01098a](https://doi.org/10.1039/d6ay01098a)
2.  Sauter M, Uhl P, Burhenne J, Haefeli WE. (2020). Ultra-sensitive quantification of the therapeutic cyclic peptide bremelanotide utilizing UHPLC-MS/MS for evaluation of its oral plasma pharmacokinetics. *J Pharm Biomed Anal*. [PMID 32353679](https://pubmed.ncbi.nlm.nih.gov/32353679/) · [doi:10.1016/j.jpba.2020.113276](https://doi.org/10.1016/j.jpba.2020.113276)

Every citation was looked up by PMID in Europe PMC (MEDLINE) on 2026-10-14 and its title matched. Citation means the paper exists and is relevant to the compound. It does not mean the paper supports any use.

## On this site

-   [PT-141 vials, sizes and prices](/pt-141-uk)
-   [PT-141 reference record](/ref/pt-141)
-   [PT-141 UK price check](/uk-price-check/pt-141)
-   [Certificates of Analysis](/coa)

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide that agonises melanocortin receptors. It is a metabolite-related analogue of Melanotan II: the C-terminal amide is replaced with a free carboxylic acid. This page summarises 2 verified PubMed papers and compares PT-141 with Melanotan II. Research use only; no human-use guidance is given.

Updated 2026-10-14