Research use only. This compound is supplied for in-vitro laboratory research by qualified researchers. It is not for human or veterinary consumption and has not been evaluated by the FDA.
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$69.99each
Tell us the Report ID or Laboratory ID shown on the certificate, and what you observed. If independent testing shows a discrepancy against our published certificate, we refund the lot in full and pull it from sale pending investigation.
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Compound information
Type
Melanocortin Research
Molecular weight
1025.18 g/mol
Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Form
Lyophilized powder
Vial strength
10mg
Catalogue number
PX-PT141-10MG
Purity
Certificate pending for this strength
Identifiers are published properties of the molecule. Values we cannot confirm are omitted rather than estimated.
Bremelanotide. The same seven-residue lactam-bridged ring as Melanotan 2 with one difference: the C-terminus is a free acid rather than an amide, which is a single oxygen and about one dalton.
Both are in the PepXtide structural library and the two can be compared side by side.
Everything else is shared: the N-terminal acetyl cap, the norleucine at position 1, the D-phenylalanine at position 4, and the 23-membered side-chain lactam joining the aspartate beta-carboxyl to the lysine epsilon-amine. The literature describes this compound as a deaminated derivative of the amide, and as a compound that may represent one of its metabolites. It was developed at Palatin Technologies and characterised as a melanocortin receptor agonist in a 2003 report.
That one-atom difference is exactly why the pair is useful on the bench. Two molecules identical apart from the C-terminal group, with measurably different receptor profiles, isolate the contribution of that group in a way few compound pairs can.
The receptor pharmacology carries an important caveat, and printing a single affinity for this compound would be misleading. Across published datasets the reported inhibition constant at MC4R differs by roughly ninety-fold depending on the cell background used: around 0.25 nanomolar in BHK570 membranes against roughly 22 to 25 nanomolar in HEK293-derived membranes, the latter figure independently reproduced by a second group. Reported values at MC1R, MC3R and MC5R vary in the same way. The compound is properly described as a non-selective melanocortin receptor agonist, and any affinity quoted for it should name its assay system and cell background rather than standing alone.
Structural work is available: a cryo-electron microscopy structure of the compound bound to MC4R in complex with Gs has been determined at approximately 3.1 angstrom resolution and deposited in the Protein Data Bank. Its protease resistance is attributed to the same two features as its amidated relative, the D-configured residue at position 4 and the conformational constraint of the 23-membered lactam.
Background
PT-141, also known as bremelanotide, is a seven-residue lactam-bridged cyclic peptide sharing the Melanotan 2 ring, differing only in carrying a free C-terminal acid instead of an amide. It keeps the N-terminal acetyl cap, norleucine at position 1, D-phenylalanine at position 4 and a 23-membered side-chain lactam. Developed at Palatin Technologies, it is characterised as a non-selective melanocortin receptor agonist, and a cryo-EM structure bound to MC4R with Gs has been deposited in the Protein Data Bank.
Specifications
Supplied as
Lyophilized powder
Available strengths
10mg
Storage
Store lyophilized at -20C, protected from light and moisture.
Intended use
In-vitro laboratory research only
Research overview
Bremelanotide
The same ring as Melanotan II, differing only at the C-terminus, which is a free acid here rather than an amide. One atom of difference between two compounds, which is why they are worth seeing side by side.
Residues
7
Atoms
144
Primary literature
We have not compiled a reading list for this compound, and would rather show nothing than pad one out.
Search the databases
The list above is a selection, not the whole literature. These open the public databases themselves, each one confirmed to return results on 29 August 2026.
PubMed, PubChem and ClinicalTrials.gov are independent scientific databases. A record or a published paper is not an endorsement of this product, and nothing indexed there describes an application, dose or outcome supported by PepXtide.
Storage & handling
Lyophilized
Store lyophilized at -20C, protected from light and moisture. The lactam ring, the D-residue and the acetylated N-terminus make the molecule a poor peptidase substrate, leaving light exposure, because of the tryptophan, and moisture uptake as the practical concerns.
Reconstituted
Once reconstituted, refrigerate at 2-8C and use within the period appropriate to the material.
Handling notes
Store the lyophilized powder at -20C, protected from light and moisture.
The lactam ring, D-residue and acetylated N-terminus make the molecule a poor peptidase substrate.
The tryptophan makes light exposure a practical concern, along with moisture uptake.
Once reconstituted, refrigerate at 2-8C and use within the period appropriate to the material.
Safety & handling
Bench handling, not a dosing guide.
Intended use
Supplied strictly as a laboratory research material for in-vitro study by qualified researchers. Not for human or veterinary use, not for ingestion or injection, and not for any clinical or diagnostic application.
Personal protective equipment
Handle with gloves, eye protection and a laboratory coat. Weigh and transfer lyophilized powder in a ventilated enclosure to avoid generating an inhalable dust.
Reconstitution
Reconstitute against the diluent and volume appropriate to your protocol, adding solvent slowly down the vial wall rather than directly onto the pellet. Do not shake. This is a handling note, not a dosing guide.
Storage after opening
Once reconstituted, refrigerate and use within the period appropriate to the material. Avoid repeated freeze-thaw cycles, which degrade peptides faster than continuous storage at the listed temperature.
Disposal
Dispose of material and containers in accordance with your institution's chemical waste procedures and applicable local regulations.
Also sold as part of a set
10mg
10mg
50mg
10ml
Melanocortin Research · 4 vials
Melanotan-2, PT-141 and GHK-Cu Set
Two melanocortin-class peptides at 10mg each and a copper tripeptide at 50mg, plus water.
On its own this set comes to $169.97 at checkout: $29.99 Bundle & Save is taken off there.
Melanotan-2 at 10mg, PT-141 at 10mg, GHK-Cu at 50mg and a 10ml bacteriostatic water vial. Four separate vials, four separate cart lines. Named for the compounds included in the set.
Melanotan-2 and PT-141 are melanocortin-receptor peptides (PT-141, bremelanotide, is a metabolite of Melanotan-2); GHK-Cu is a copper-binding tripeptide. Melanotan-2 and PT-141 are listed under Melanocortin Research; GHK-Cu is listed under Matrix & Cytoskeletal.
Adds 4 separate cart lines. Remove any one of them in the cart.
Supplied for in-vitro laboratory research only. Not for human or veterinary consumption, and not evaluated by the FDA. No statement on this page describes an application, benefit, dose, route or outcome. Descriptions are structural and mechanistic, and reference data such as CAS numbers and molecular formulas is published information about the compound itself, provided for identification. No measured result is shown for this strength because a certificate has not yet been published for its lot.
10mg
10mg
50mg
10ml