PT-141 (Bremelanotide): the MC4R Sexual-Function Research Peptide (Australia Guide)

PT-141 (Bremelanotide, sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH) is a cyclic heptapeptide melanocortin-receptor agonist. It is the only melanocortin compound to have reached full regulatory approval in any market: in 2019 the US FDA approved Bremelanotide under the brand name Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.

What makes PT-141 distinct as a research tool is where it acts. PDE5 inhibitors (sildenafil, tadalafil) work peripherally on vascular smooth muscle. PT-141 instead acts centrally, in the hypothalamus and limbic system, to modulate sexual-motivation and desire circuits. That central, melanocortin-receptor mechanism is the reason it is studied as a category separate from every vascular-acting agent.

PT-141 was derived from the broad-spectrum melanocortin agonist Melanotan II. This page focuses on PT-141's sexual-function / MC4R research role. For melanogenesis, MC1R pigmentation, the full five-receptor melanocortin family, and the parent-compound chemistry, see: Melanotan II research guide →

The melanocortin system signals through five receptors (MC1R–MC5R). PT-141's research value comes from its relative selectivity for the central receptors MC3R and MC4R, with markedly reduced activity at MC1R, the pigmentation receptor that dominates Melanotan II's profile.

• MC4R is expressed throughout the central nervous system, concentrated in the hypothalamus, and is the receptor most directly implicated in sexual-motivation signalling. It is PT-141's primary research target.
• MC3R is expressed in hypothalamic and limbic circuits involved in energy balance and reward, and contributes to the centrally-mediated response.
• Reduced MC1R activity means PT-141 produces minimal pigmentation effects, letting researchers isolate central sexual-function pathways without the confounding melanogenesis seen with non-selective agonists.

For researchers who specifically need the full melanocortin profile (including MC1R-driven melanogenesis), the non-selective parent compound is the appropriate tool, covered in the Melanotan II guide.

PT-141 occupies a unique position in sexual-function research because its mechanism does not overlap with the dominant pharmacology in the field:

• PDE5 inhibitors (sildenafil, tadalafil): peripheral, vascular; act on smooth-muscle blood flow.
• PT-141 (Bremelanotide): central, neural; acts on hypothalamic melanocortin circuits governing desire and motivation.

Because the two mechanisms are independent, PT-141 has been studied in research contexts where vascular-acting agents are not the relevant model, most notably as the basis for a centrally-mediated approach to sexual desire and motivation.

• Female sexual desire (the basis for approval): Bremelanotide's Phase 3 clinical development program, known as RECONNECT, evaluated the compound in premenopausal women with HSDD and supported its 2019 FDA approval as Vyleesi. This is the single most consequential body of evidence defining PT-141's research identity.
• Centrally-mediated mechanism: PT-141 acts on hypothalamic/limbic melanocortin circuits rather than peripheral vasculature, distinguishing it from PDE5 inhibitors and making it a research tool for the central regulation of sexual motivation.
• Melanocortin CNS pathway research: MC3R and MC4R are widely expressed in hypothalamic circuits involved in energy balance, reward, and autonomic function; PT-141's relative MC3R/MC4R selectivity makes it a probe for these pathways in isolation from pigmentation effects.
• Transient blood-pressure response: Bremelanotide produces transient increases in blood pressure, a documented pharmacological characteristic that was a key consideration during its clinical development and remains a focus of cardiovascular research.

OzPeps stocks research-grade PT-141 (Bremelanotide) with fast AU shipping. View PT-141 stock and pricing →

PT-141 is sold strictly for in-vitro laboratory research. Not TGA-approved in Australia. Not for human or animal consumption. Researchers are responsible for all applicable regulatory compliance.