PT-141 (Bremelanotide)
Also known as Bremelanotide, PT 141, melanocortin agonist peptide
PT-141 (bremelanotide) is a cyclic melanocortin-receptor agonist peptide derived from the α-MSH lineage, studied as a centrally acting probe of melanocortin signaling. A research-use profile.
PT-141, known in the literature as bremelanotide, is a cyclic peptide that sits in the melanocortin family. It descends structurally from Melanotan II — it is the ring-opened metabolite that lost the terminal amide — and, like its parent, it acts as an agonist at melanocortin receptors rather than on the vascular or hormonal pathways most peptides in a catalog target.
What makes it a distinct object of research interest is where it acts. Melanocortin signaling relevant to PT-141 is studied as a central-nervous-system pathway, not a peripheral one. This page describes that receptor system and the compound's structure. It does not describe outcomes, indications, or use — those are neither settled here nor appropriate to claim for a research compound.
A cyclic heptapeptide analog of α-melanocyte-stimulating hormone (α-MSH). It is a metabolite-derived, ring-closed structure that includes non-proteinogenic residues (an N-terminal acetyl group and a D-configured phenylalanine), which is why it is described by its analog relationship to α-MSH rather than a simple linear one-letter sequence.
The melanocortin receptor angle
The melanocortin system is a family of five G-protein-coupled receptors (MC1R through MC5R). PT-141 is studied as a non-selective agonist across several of them, with particular research attention on MC4R, a receptor expressed heavily in the central nervous system. That CNS localization is the reason PT-141 is framed as a centrally acting probe: the pathway it engages is a signaling system in the brain, distinct from the peripheral messengers other libido-adjacent research compounds are grouped with.
Because it is an agonist rather than a hormone or a growth factor, PT-141 is of interest to researchers mapping how melanocortin tone is transmitted and modulated — the receptor pharmacology itself, not a downstream promise.
How it relates to Melanotan II
PT-141 and Melanotan II share a common cyclic core. The practical difference researchers note is that PT-141 is the des-amide metabolite: it corresponds to the form of the molecule after the C-terminal amide is cleaved. This is why the two compounds are always discussed together and why their receptor profiles overlap while their downstream research contexts diverge.
The shared scaffold also explains the structural caveats. Both carry non-standard residues, so neither is well represented by a plain proteinogenic sequence — they are described by their analog relationship to α-MSH.
Reading a PT-141 certificate of analysis
Because PT-141 is a small cyclic peptide with a defined mass, a certificate of analysis should present a mass-spectrometry value consistent with the cyclic heptapeptide and an HPLC trace dominated by a single peak. A lot that lists a purity number without the analytical method behind it, or without a batch identifier, tells you less than it appears to. Verify any lot against its own certificate by batch number.
These are research areas the compound is associated with in the literature — not medical claims or intended uses.
Handling & storage
Supplied lyophilized. Kept sealed and cold; in research settings it is reconstituted with bacteriostatic water only when a protocol calls for it, then refrigerated. Handle per accepted laboratory practice.
Verify a certificate by lot →Common questions
It is studied as an agonist at melanocortin receptors, with particular research attention on MC4R, a receptor concentrated in the central nervous system.
PT-141 (bremelanotide) is the des-amide metabolite of Melanotan II. The two share a cyclic peptide core, which is why they are so often discussed side by side.
It is a cyclic molecule containing non-standard residues (including an acetyl cap and a D-configured phenylalanine), so it is described by its analog relationship to α-MSH rather than a simple one-letter chain.
This monograph is a research-use reference. It describes composition and the contexts in which the compound has been studied — it is not medical advice, a description of effects, or a recommendation for use. Sold strictly for laboratory and research use; not for human or animal consumption.