PT-141 (Bremelanotide) 10mg

PT-141, known in clinical literature as bremelanotide, is a cyclic heptapeptide: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH.

Compare that sequence with Melanotan-2 and one position differs. Where MT-2 terminates in an amide, PT-141 terminates in a free carboxylic acid. PT-141 is the deaminated derivative of MT-2 and a likely metabolite of it, sharing the same lactam-bridged ring scaffold. A single terminal substitution separating two distinct pharmacological profiles is a useful illustration of how much terminal chemistry matters in cyclic peptides.

Reported binding puts MC4R affinity at a Ki near 2.6 nM and MC3R near 12 nM, roughly fivefold selectivity for MC4R over MC3R. The lactam constraint is credited with favouring the MC3R and MC4R binding pocket.

One caveat on the published pharmacology: sources disagree on where MC1R sits in the potency ranking. Some order the receptors with MC1R first, while the design intent is described as concentrating activity at the central MC3R and MC4R subtypes. If receptor selectivity is central to your work, go to the primary binding studies rather than to any summary, including this one.

Published research covers melanocortin receptor pharmacology, MC4R structural biology, and central nervous system signalling through that receptor.

Supplied as a lyophilised powder at ≥99% purity by HPLC, with batch LC-MS identity confirmation and a certificate of analysis. Reconstitute with bacteriostatic water. Store the sealed vial at -20°C and keep reconstituted solution at 2-8°C, protected from light.

For in-vitro laboratory research only. Not for human or veterinary use.