What is PT-141 (Bremelanotide)?
PT-141, also known as Bremelanotide, is a synthetic cyclic heptapeptide analogue of α-melanocyte-stimulating hormone (α-MSH). It was identified as the active carboxyl-terminal metabolite of Melanotan II — Melanotan II with the C-terminal amide replaced by a free carboxylic acid — and, like its parent, is an agonist at the melanocortin receptors MC3R and MC4R.
Unlike compounds that act on vascular smooth muscle, PT-141's activity in animal models is centrally mediated: MC4R is densely expressed in the hypothalamus, and the compound is used in research to probe melanocortin signalling in appetite, energy balance and sexual-behaviour circuits. Its cyclic lactam bridge (Asp–Lys) gives it greater receptor selectivity and stability than linear α-MSH fragments.
ClaraScience supplies PT-141 in 10mg vials, HPLC-tested to 99.3% purity, with a full Certificate of Analysis included with every batch. For laboratory research use only.
Class. Cyclic α-MSH analogue; melanocortin MC3R/MC4R agonist.
Research focus. Melanocortin receptor pharmacology, hypothalamic signalling, centrally mediated arousal and feeding-behaviour models.
Sequence. Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (1025.18 g/mol).
Research Background
PT-141 emerged from the Melanotan programme at the University of Arizona, where α-MSH analogues were developed as photoprotective tanning agents; the unexpected central effects of Melanotan II led to the isolation of its metabolite, bremelanotide, as a selective research tool for melanocortin signalling. Diamond et al. (2004) characterised its pharmacology and early human tolerability.
The compound has since been widely used in receptor-binding and functional assays across the melanocortin family (MC1R–MC5R), in rodent models of sexual behaviour and feeding, and as a comparator for newer MC4R ligands. In 2019 a bremelanotide injection was approved by the US FDA under a prescription brand for a specific indication in premenopausal women; that product is a regulated medicine and is unrelated to research-grade material.
ClaraScience PT-141 is supplied as a research reagent only. It has not been evaluated or approved by the TGA, and the research literature summarised here is not a claim of therapeutic effect.
Key citation Diamond LE, Earle DC, Rosen RC, Willett MS, Molinoff PB. "Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild to moderate erectile dysfunction." Int J Impot Res. 2004;16(1):51–59.
Specifications
| Common Name |
PT-141 · Bremelanotide |
| Sequence |
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH |
| Molecular Formula |
C₅₀H₆₈N₁₄O₁₀ |
| Molecular Weight |
1025.18 g/mol |
| CAS Number |
189691-06-3 |
| Receptor targets |
MC4R (primary), MC3R; lower affinity at MC1R/MC5R |
| Purity (HPLC) |
99.3% — full COA with every batch |
| Vial Size |
10mg lyophilised powder |
| Storage |
2–8°C (short-term) · −20°C (long-term) |
| Primary Reference |
Diamond LE et al., Int J Impot Res 2004;16:51–59 |
Storage & Handling
- Unopened vial: 2–8°C for regular use; −20°C for long-term storage. Protect from light.
- After reconstitution: 2–8°C, use within 28 days. Avoid freeze-thaw cycles.
- Reconstitution: Sterile bacteriostatic water. Use our free reconstitution calculator.
Full protocols: Storage & Handling Guide · Reconstitution Guide.
Ordering & Pricing — Australia
| Quantity |
Price per unit |
Saving |
| 1–4 units |
$69.95 AUD |
— |
| 5–9 units |
$64.95 AUD |
Save 7% |
| 10+ units |
$59.95 AUD |
Save 14% |
PT-141 is currently available on pre-order — reserve now and your vials ship as soon as the next batch lands in our Australian warehouse. Free priority tracked shipping on orders over $250 AUD. Wholesale enquiries welcome.
Frequently Asked Questions
What is PT-141?
PT-141 (Bremelanotide) is a cyclic heptapeptide melanocortin-receptor agonist derived from α-MSH. It is the carboxyl-terminal metabolite of Melanotan II and acts at MC3R and MC4R. ClaraScience supplies it for laboratory research only.
How does PT-141 differ from Melanotan II?
Melanotan II has a C-terminal amide; PT-141 has a free carboxylic acid at the same position. The change reduces the pigmentation activity associated with MC1R while retaining MC3R/MC4R agonism, which is why PT-141 is used as a more selective research tool for central melanocortin signalling. See Melanotan II.
Is PT-141 the same as the approved medicine?
No. A pharmaceutical bremelanotide injection is a registered prescription medicine in the United States. ClaraScience PT-141 is research-grade material that has not been evaluated by the TGA and is not a medicine; it is supplied for in-vitro and preclinical research only.
Is PT-141 approved by the TGA?
No. PT-141 has not been approved by the TGA for any use. For laboratory research use only — not for human or animal use, and not approved by the TGA for therapeutic use.
Is PT-141 available in Australia?
ClaraScience supplies PT-141 in 10mg vials from an Australian warehouse, currently on pre-order. A Certificate of Analysis is provided with every batch.
