PT-141 in Australia: a melanocortin-receptor (MC4R) research guide

PT-141 in Australia. PT-141 (bremelanotide) is a synthetic cyclic heptapeptide referenced across the melanocortin-receptor research literature — an α-melanocyte-stimulating-hormone (α-MSH) analogue built on the same lactam scaffold as Melanotan II, with the MC4R receptor the principal receptor of research interest. This guide is a research-reference summary for Australian researchers focused strictly on receptor pharmacology. It makes no medical, sexual-function, or human-use claim.

The melanocortin system and MC4R

The melanocortin receptors are a family of five class-A G-protein-coupled receptors — MC1R through MC5R — that respond to the melanocortin peptides derived from pro-opiomelanocortin (POMC), including α-MSH. MC4R is expressed predominantly in the central nervous system and is the receptor of principal interest in PT-141 research. Because the endogenous agonists are short-lived, stabilised synthetic analogues are used as research tools to interrogate melanocortin-receptor pharmacology in controlled laboratory models — and PT-141 is one such tool, studied for its receptor activity rather than any physiological outcome.

Where PT-141 sits in the literature

PT-141 is characterised in the melanocortin-pharmacology literature as an agonist at melanocortin receptors including MC3R and MC4R (Molinoff and colleagues, Annals of the New York Academy of Sciences, 2003), with MC4R the principal receptor of research interest. It derives from the cyclic lactam α-melanotropin scaffold reported by Al-Obeidi and colleagues (Journal of Medicinal Chemistry, 1989) and is covered in the melanocortin-receptor pharmacology review of Shadiack and colleagues (Current Topics in Medicinal Chemistry, 2007). It is used as a defined melanocortin-receptor reference ligand in receptor-pathway research.

PT-141 and Melanotan II

PT-141 is the C-terminal-free-acid analogue of Melanotan II: the two share the identical cyclic lactam scaffold and differ only at the C-terminus — a free carboxylic acid on PT-141 versus an amide on Melanotan II. Where Melanotan II is referenced as a broad, non-selective MC1R–MC5R agonist, PT-141 is studied as more MC4R-focused. That single-residue difference is exactly why the two are compared in melanocortin-receptor research — to probe how C-terminal chemistry affects receptor recognition and subtype selectivity. See the Melanotan 2 melanocortin research guide for the broad-spectrum counterpart.

Identity, purity and the COA moat

Every batch of PT-141 supplied by Elite AU Peptides is independently HPLC-tested by Janoshik before it is listed. The measured purity is published on the PT-141 product page and in the lab-reports library — a real batch number, the measured percentage rather than a marketing figure, and a report you can verify independently at janoshik.com. PT-141 is stocked in a 10mg lyophilised vial; nothing is listed without a certificate on file.

Reconstitution and handling for research use

PT-141 ships as a lyophilised powder. Reconstitute with bacteriostatic water for laboratory handling — a 10mg vial in 2mL yields a 5mg/mL working stock; adjust to the concentration your protocol requires. Store the lyophilised powder at −20°C protected from light; once reconstituted, refrigerate at 2–8°C and use within the documented research window.

Compliance and research-use framing

PT-141 is not supplied as a TGA-approved therapeutic good and is not for human or animal consumption. Elite AU Peptides supplies it strictly for in-vitro and laboratory research use only. We make no medical, sexual-function, or human-use claim about this compound; the material above is a research-reference summary of the published melanocortin-receptor literature, framed on receptor pharmacology only. Researchers should consult primary peer-reviewed sources for receptor-binding affinities and protocol-specific reference values, and are responsible for the regulatory and institutional requirements that apply to their work.