What is PT-141?
PT-141 (international non-proprietary name: Bremelanotide) is a cyclic heptapeptide derived from the lactam analogue of α-melanocyte-stimulating hormone (α-MSH). Structurally it is the deaminated, ring-stabilised metabolite of Melanotan II — the C-terminal lysine residue is hydrolysed to a free carboxylic acid, which subtly shifts the receptor-binding profile.
PT-141 acts as a non-selective agonist at the melanocortin-3 (MC3R) and melanocortin-4 (MC4R) receptors. MC4R signalling in the hypothalamus and limbic system has been the principal focus of research interest, particularly in studies of CNS-mediated arousal pathways and central appetite regulation.
ClaraScience supplies PT-141 as a lyophilised powder in 10mg vials. Each batch is independently HPLC-tested to ≥99.0% purity (99.30% verified this batch) at a WHO/GMP-certified laboratory, with a full COA including HPLC chromatogram and mass spectrometry confirmation included with every order. All products are supplied for laboratory research use only.
Mechanism. Non-selective MC3R / MC4R melanocortin receptor agonism — distinct from peripheral MC1R-mediated pigmentary signalling.
Structure. 7 amino acids · cyclic ring closure via Asp-Lys lactam · 1025.18 g/mol.
Research context. CNS receptor binding, hypothalamic signalling, autonomic pathway research models.
Research Background
PT-141 emerged from Palatin Technologies' work on cyclic α-MSH analogues in the late 1990s, initially developed as a tan-promoting candidate before researchers observed unexpected CNS-mediated effects in animal models. The seminal early study by Diamond et al. (2004, Int J Impot Res) demonstrated that subcutaneous PT-141 produced measurable behavioural responses distinct from peripheral vasodilator mechanisms, establishing the compound's central nervous system pharmacology as a research domain in its own right.
Subsequent receptor-binding work by Molinoff et al. (2003, Ann N Y Acad Sci) characterised PT-141's binding affinity profile across the five melanocortin receptor subtypes, confirming MC3R and MC4R as the primary high-affinity targets with substantially weaker MC1R activity than Melanotan II. This receptor selectivity profile underpins much of the published preclinical research on the compound.
PT-141 has been the subject of Phase II and Phase III clinical research programmes investigating melanocortin-pathway pharmacology, and is widely used as a reference MC4R agonist in academic receptor-binding and CNS-signalling research.
PT-141 is commonly studied alongside Melanotan II as a receptor-selectivity comparator — both are α-MSH-derived cyclic heptapeptides with overlapping but non-identical receptor-binding profiles.
Key citation Diamond LE, Earle DC, Rosen RC, et al. "Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist." Int J Impot Res. 2004;16:51–59.
Compound Specifications
| Common Name |
PT-141 (Bremelanotide) |
| Structure |
Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH · cyclic heptapeptide |
| Molecular Weight |
1025.18 g/mol |
| Receptor Targets |
MC3R / MC4R agonist (non-selective) |
| Purity (HPLC) |
≥99.0% (99.30% verified this 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
PT-141 is supplied as a lyophilised powder in sealed vials. ClaraScience ships all orders in plain, discreet packaging from our Australian warehouse.
- Unopened vial: 2–8°C for regular use; −20°C for longer-term storage.
- After reconstitution: Store at 2–8°C and use within 28 days. Avoid repeated freeze-thaw cycles.
- Reconstitution solvent: Sterile bacteriostatic water. Use our free reconstitution calculator for the exact volume.
Full protocols in our Storage & Handling Guide.
Ordering & Pricing — Australia
| Quantity |
Price per vial |
Saving |
| 1–4 vials |
$69.95 AUD |
— |
| 5–9 vials |
$64.95 AUD |
Save 7% |
| 10+ vials |
$59.95 AUD |
Save 14% |
Free priority tracked shipping on orders over $250 AUD. Dispatched within 24 hours. For bulk orders, see our wholesale enquiry page.
Frequently Asked Questions
What is PT-141?
PT-141 (Bremelanotide) is a cyclic heptapeptide derived from α-MSH. It is a non-selective agonist at the MC3R and MC4R melanocortin receptors with substantially reduced MC1R activity compared to its parent compound Melanotan II. All ClaraScience products are for laboratory research use only.
How is PT-141 different from Melanotan II?
PT-141 is the metabolite of Melanotan II — the C-terminal Lys is hydrolysed to a free carboxylic acid. This subtle structural change reduces MC1R binding (and therefore pigmentary activity) while retaining MC3R/MC4R agonism, shifting the research profile toward CNS-mediated melanocortin signalling rather than peripheral melanocyte stimulation.
What receptors does PT-141 target?
PT-141 binds with high affinity to the melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R), with weaker affinity at MC1R, MC2R and MC5R. MC4R signalling in the hypothalamus is the most actively studied pathway in the published research literature.
Is PT-141 available in Australia for research?
ClaraScience supplies research-grade PT-141 from an Australian warehouse. Products are for laboratory research use only and have not been evaluated by the TGA for therapeutic purposes in this context.
What purity is your PT-141?
≥99.0% HPLC-verified at a WHO/GMP-certified third-party laboratory (99.30% this batch). Full COA with HPLC chromatogram and mass spectrometry confirmation included with every batch.
