Buy PT-141 UK

Melanocortin research depends on knowing precisely which analogue is in the vial, because the compounds in this family differ from one another by very small structural margins and behave differently as a result. Every order of PT-141 ships with a batch-specific Certificate of Analysis recording the HPLC-measured purity for that production lot at 99%+, and recent certificates are published in our on-site COA library so you can review the format before committing. Vials are handled cold-chain through to dispatch and ship as pre-mixed solutions, so there is no reconstitution step at your end. Orders confirmed before the daily cut-off leave a UK facility the same working day on tracked next-working-day delivery, which keeps the transit window short and predictable. Larger or recurring requirements are handled through our trade desk. Everything is supplied for in-vitro laboratory research only.

PT-141, also known as bremelanotide, is a synthetic cyclic heptapeptide derived structurally from Melanotan II. It is built by modifying the C-terminus of the MT-II scaffold — replacing the terminal amide with a hydroxyl group — which yields a closely related cyclic peptide with a distinctly different receptor-selectivity profile while retaining the lactam-bridged, enzymatically stable architecture of its parent compound.

In biochemical and cellular systems PT-141 acts as an agonist at the centrally expressed melanocortin receptors MC3R and MC4R, with comparatively higher potency at MC4R and substantially reduced activity at MC1R relative to Melanotan II. That shift toward MC4R selectivity is the reason it appears so often in mechanistic work: it lets investigators isolate MC4R-mediated signalling — G-protein-coupled cAMP and phospholipase-C cascades, intracellular calcium flux, and ERK/MAPK pathway activation — from the broader melanocortin response that a non-selective agonist produces. Reported observations vary with receptor subtype, concentration, exposure time and model system, so the compound is best understood as a tool for characterising melanocortin-receptor signalling rather than as having any fixed effect.

This page describes PT-141 strictly within that laboratory research framing. It is supplied for in-vitro research use only, and nothing here describes dosing, administration, or any application in humans or animals, nor does it make therapeutic claims.

Because PT-141 is a direct structural derivative of Melanotan II, the two are frequently studied side by side in receptor-selectivity work. The structural difference is a single change at the C-terminus: Melanotan II is amidated, PT-141 carries a free acid. Everything else — the norleucine substitution, the D-phenylalanine, the lactam bridge that cyclises and stabilises the molecule — is shared.

That makes the pair unusually useful as a controlled comparison. Melanotan II is a broad, non-selective agonist across MC1R, MC3R, MC4R and MC5R, with negligible activity at MC2R, whereas PT-141 concentrates activity at MC4R. Running both within the same experimental system lets a researcher attribute a difference in response to receptor selectivity rather than to unrelated structural variation, which is far harder to do when comparing two structurally dissimilar compounds.

We supply both, so a laboratory can source the comparator and the test compound with matching documentation and handling. See our guides on [PT-141](/guides/what-is-pt-141) and [Melanotan II](/guides/what-is-melanotan-2) for the underlying pharmacology.