PT-141

Bremelanotide — cyclic melanocortin receptor agonist

A cyclic seven-residue peptide that acts as a non-selective agonist at melanocortin receptors. It is the free-acid form of Melanotan II, and the two are separated by a single atom — which is the main thing worth checking on any certificate.

Mechanism

Binds melanocortin receptors, with activity reported at MC1R, MC3R and MC4R rather than selectively at one of them. Unlike the compounds it is often grouped with, its described activity is central rather than peripheral — which is why it appears in receptor-pharmacology work rather than in vascular models.

Areas of research

• Melanocortin receptor pharmacology and subtype selectivity
• Cyclic-peptide stability and conformational constraint
• Central nervous system peptide signalling
• Structure–activity comparison with linear melanocortin analogues

Identity and specification

One atom from Melanotan II — and the weight is the tell

This is the specification most often got wrong with this compound, and it is worth a moment. PT-141 is the free acid; Melanotan II is the C-terminal amide of the same cyclic heptapeptide. Chemically that is one NH replaced by one O. Under a mass spectrometer it is 0.98 daltons, and the two compounds have entirely separate registry numbers.

So: a certificate for material sold as PT-141 that reports a mass near 1024 is describing Melanotan II, not this compound. One dalton is easy to dismiss as rounding. It is not rounding — it is a different substance. We stock Melanotan II as well, deliberately listed and priced separately, because they are not interchangeable.

Regulatory position — stated plainly

Bremelanotide is licensed as a prescription medicine in some jurisdictions. Nothing on this page concerns that use. This material is supplied for in-vitro laboratory research only: it is not a licensed medicine here, it is not for human or veterinary administration, and we do not provide guidance on dosing or use. Card payment is not available for this compound — bank transfer or cryptocurrency only.

Handling and storage

Supplied lyophilised and stable in transit at ambient temperature, which is why it ships dry. Store the sealed vial at −20°C, protected from light. Reconstitute with bacteriostatic or sterile water run down the vial wall, never onto the powder; swirl, do not shake. Keep reconstituted material refrigerated. See how to reconstitute research peptides and which solvent to use.

Sizes and pricing

Independently batch tested. A batch-specific certificate of analysis is available on request — ask for the certificate for the batch we would ship you before you order. Published certificates are in the COA library, each with the issuing laboratory’s verification key.

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