PT-141 (bremelanotide) is a cyclic melanocortin peptide that preferentially engages the MC3R and MC4R receptors, the melanocortin subtypes concentrated in the central nervous system. Research studies it for central melanocortin signaling. It is a laboratory research compound and is not for human use.

Which receptors does PT-141 target?

It preferentially engages MC3R and MC4R, the central-nervous-system melanocortin receptors. This sets it apart from Melanotan-2, a broader melanocortin agonist with notable MC1R activity. The receptor preference is what determines which pathway each is used to study.

How is PT-141 related to Melanotan-2?

PT-141 is a metabolite of Melanotan-2, differing at the C-terminus. That small structural change shifts its receptor preference toward the central MC3R and MC4R subtypes, whereas Melanotan-2 acts more broadly across the melanocortin receptors including MC1R.

Compound Profile3 min readUpdated May 27, 2026

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What is PT-141?
What does the research literature study?
How it relates to Melanotan-2
Handling and storage
Sources and further reading

PT-141: Compound Profile

PT-141 is the MC3R/MC4R-preferring member of the melanocortin peptide class. This profile covers its identity, the receptor mechanism the literature attributes to it, and how it relates structurally to Melanotan-2. For where it sits in the class, see the melanocortin peptides overview, and for the receptor family, the melanocortin receptor map.

What is PT-141?#

PT-141, also called bremelanotide, is a cyclic peptide agonist of the melanocortin receptors. Structurally it is closely related to Melanotan-2: PT-141 is a metabolite of that molecule, differing at the C-terminus, and that small change shifts its receptor preference toward the MC3R and MC4R subtypes. Those are the melanocortin receptors concentrated in the central nervous system, which is why PT-141 is studied for central rather than peripheral melanocortin signaling.

Attribute	Value
Common name	PT-141 (bremelanotide)
Class	Cyclic melanocortin-receptor agonist (heptapeptide)
Receptor preference	MC3R and MC4R
CAS number	189691-06-3
Structural relation	Metabolite of Melanotan-2 (differs at the C-terminus)
Primary study area	Central melanocortin (MC3R/MC4R) signaling research

PT-141 molecular identity, as commonly reported in the literature and chemical databases.

Two-dimensional structure of PT-141, a cyclic melanocortin heptapeptide (bremelanotide). Surgical-green heteroatoms (N, O) over a white skeleton on a dark background. — PT-141 · cyclic melanocortin heptapeptide (bremelanotide) · structure rendered from PubChem CID 9941379 via RDKit.

What does the research literature study?#

PT-141 is studied as a tool for probing the central melanocortin receptors. Its preference for MC4R in particular makes it relevant to research on that receptor's signaling, distinct from the MC1R-driven pigmentation pathway that broader agonists engage. The work is receptor pharmacology and preclinical research; it does not establish outcomes in people, and this profile addresses mechanism only.

How it relates to Melanotan-2#

PT-141 and Melanotan-2 are structurally linked, with PT-141 being a metabolite of Melanotan-2. The functional difference is receptor breadth: Melanotan-2 is a broad melanocortin agonist with notable MC1R activity, while PT-141 shifts toward the central MC3R/MC4R subtypes. The melanocortin receptor map lays out which receptor drives which pathway.

Handling and storage#

PT-141 comes lyophilized and is reconstituted before use. As a cyclic peptide it is reasonably stable, but storage is the same as for the rest of the catalog: the reconstitution primer covers solvent choice, and the cold-chain article covers stability once reconstituted.

Nexara catalogs PT-141 (10mg) at ≥99% purity for laboratory research. Independent third-party COA delivery is paused during the transition to a new testing laboratory; see research compliance.

Frequently asked

What is PT-141?: PT-141 (bremelanotide) is a cyclic melanocortin peptide that preferentially engages the MC3R and MC4R receptors, the melanocortin subtypes concentrated in the central nervous system. Research studies it for central melanocortin signaling. It is a laboratory research compound and is not for human use.
Which receptors does PT-141 target?: It preferentially engages MC3R and MC4R, the central-nervous-system melanocortin receptors. This sets it apart from Melanotan-2, a broader melanocortin agonist with notable MC1R activity. The receptor preference is what determines which pathway each is used to study.
How is PT-141 related to Melanotan-2?: PT-141 is a metabolite of Melanotan-2, differing at the C-terminus. That small structural change shifts its receptor preference toward the central MC3R and MC4R subtypes, whereas Melanotan-2 acts more broadly across the melanocortin receptors including MC1R.

Sources and further reading#

Hadley & Dorr, melanocortin receptor agonists (the melanotan / bremelanotide lineage), Peptides 2006 (PMID 16426078): review of the melanocortin-agonist class to which PT-141 belongs.

For research use only. Not for human consumption, diagnosis, treatment, or prevention of any disease. All products are intended solely for laboratory research purposes.

Last updated: 2026-05-27