Research library / Compounds

What is ?

A cyclic melanocortin peptide, one chemical group away from the compound it came from.

is a synthetic cyclic peptide of seven amino acids that activates melanocortin receptors, the receptor family that α-MSH acts on. It was developed from and differs from it by a single chemical group. In clinical literature the same molecule is called bremelanotide. Prism Labs supplies it as a 10 mg lyophilized vial.

Prism Labs editorial · Updated October 8, 2026 · 3 min read

Lyophilized vial10mg · 99.40% purity$44.99View product

What it is

Its structure is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH: an acetylated norleucine followed by a six-residue ring closed between aspartic acid and lysine. The reference record lists the formula C50H68N14O10 and a molecular weight of 1025.2 g/mol (PubChem CID 9941379).

It contains two residues outside the standard twenty, norleucine and D-phenylalanine, so the identity result on the COA is the reliable check.

Sources: [1] PubChem · reference structure

Where it came from

Melanocortins are peptide hormones, α-MSH among them. Researchers designed long-acting linear and cyclic analogues. Palatin Technologies later developed a new analogue of the cyclic : .

The two differ at one end of the chain. ends in an amide (–NH2); ends in a free acid (–OH), which is why its formula has one more oxygen and one fewer nitrogen.

For the parent compound’s structure, its 1989 design and the receptors it acts on, see What is ?

Sources: [3] Peptides · 2006 · [4] Drugs · 2019 · [2] PubChem · reference structure · [1] PubChem · reference structure

Lyophilized vial from Prism Labs — Every lot ships with its own certificate of analysis.

What researchers have studied

Its literature centers on melanocortin receptors:

It activates several melanocortin receptor subtypes; reviews identify MC4R as the most relevant.
MC4R is concentrated in the hypothalamus, and much of the research maps its role in brain pathways of sexual response.
Clinical development under the name bremelanotide, summarized in a 2019 profile.

These are observations in laboratory models. They are not evidence about any use in people.

Sources: [5] CNS Spectrums · 2022 · [4] Drugs · 2019

How it is supplied and stored

ships as a lyophilized (freeze-dried) powder in 10 mg vials. The powder is stable at room temperature in transit. For lab use it is reconstituted with bacteriostatic water such as .

Concentration is content divided by volume: 10 mg in 2 mL gives 5 mg per mL. The reconstitution calculator handles other combinations.

For storage before and after reconstitution, see how to store lyophilized peptides.

How to verify a batch

Every lot has its own certificate of analysis from an independent lab. Read three results separately:

Identity: confirms the expected compound was detected.
Purity: the share of the measured material that is the intended compound.
Content: the amount measured, compared with the label.

Then match the lot number on your vial or bottle to the report, and use the report’s verification link to confirm it with the testing lab. Step by step: how to read a peptide COA.