PT-141 (Bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist derived from the Melanotan II analog series. It is studied in research contexts examining melanocortin receptor pharmacology, central nervous system arousal circuits, and energy homeostasis pathways. This overview covers its pharmacology, published research, and laboratory specifications for qualified researchers.
What Is PT-141?
PT-141 (cyclo-[Nle-Asp-His-D-Phe-Arg-Trp-Lys]) is a cyclic analog of alpha-melanocyte-stimulating hormone (α-MSH) and a metabolite of Melanotan II formed by hydrolysis of the C-terminal amide. Unlike Melanotan II, PT-141 lacks the C-terminal amide group, resulting in a distinct pharmacokinetic and receptor selectivity profile. PT-141 acts as an agonist at melanocortin receptor subtypes MC1R, MC3R, and MC4R with highest affinity at MC4R. The peptide was investigated clinically by Palatin Technologies and received FDA approval in 2019 (brand name Vyleesi) as the first melanocortin receptor agonist approved for hypoactive sexual desire disorder (HSDD) — providing a well-characterized clinical pharmacology dataset for researchers.
Mechanism of Action
PT-141 activates melanocortin receptors, which are Gαs-coupled GPCRs that stimulate adenylyl cyclase and elevate cAMP. MC4R is expressed in the hypothalamus (particularly the paraventricular nucleus), spinal cord, and limbic structures. In CNS research models, MC4R activation has been associated with modulation of dopaminergic circuits involved in motivational behavior and energy expenditure regulation. MC3R activation contributes to energy homeostasis research, with roles in adipokine signaling and autonomic function. The peptide’s cyclic structure confers partial resistance to peptidase degradation, extending its research utility relative to linear α-MSH analogs.
Published Research Highlights
Diamond et al. (J Sex Med 2004) conducted early phase clinical studies characterizing PT-141’s pharmacological effects in humans. The RECONNECT trial program (Palatin Technologies, 2016–2018) examined PT-141 in women with HSDD in two Phase 3 RCTs, providing the clinical data package supporting FDA approval. Melanocortin receptor research using PT-141 as a tool compound has contributed to understanding MC3R/MC4R roles in feeding behavior, autonomic regulation, and nociception. The compound is used in pharmacological studies requiring selective CNS melanocortin pathway activation, and as a reference standard in competitive binding assays for MC3R and MC4R.
Research Use Only. PT-141 is supplied by Bastion Peptides strictly for in vitro and laboratory research purposes. Not for human or veterinary use. Not for administration to humans outside of clinical trial contexts.
Laboratory Specifications
| Parameter | Specification |
|---|---|
| Molecular Formula | C₅₀H₆₈N₁₄O₁₀ |
| Molecular Weight | 1,025.18 Da |
| Structure | Cyclic heptapeptide; cyclo-[Nle-Asp-His-D-Phe-Arg-Trp-Lys] |
| Purity | ≥99% (HPLC verified) |
| Third-Party COA | Janoshik Analytical — available on request |
| Storage | −20°C lyophilized; 4°C in solution (use within 14 days) |
| Appearance | White lyophilized powder |
Reconstitution Protocol
Reconstitute PT-141 with bacteriostatic water or sterile saline by adding solvent along the vial wall and swirling gently. The cyclic peptide is readily water-soluble. Typical research concentrations range from 1–10 mg/mL. Store at 4°C and use within 14 days of reconstitution. Protect from repeated freeze-thaw. Bacteriostatic Water (10 mL) is available from Bastion Peptides.
Available Formats
Bastion Peptides supplies PT-141 at 10mg per vial, HPLC verified to ≥99% purity with Janoshik COA per batch. View current inventory in the shop.
For research use only. Not approved for unsupervised human use. Researchers are responsible for compliance with all applicable local regulations governing research compound procurement and use.
