PT-141

PT-141 (10mg) — Melanocortin-4 Receptor Agonist Research Peptide

PT-141 (10mg) is supplied in Australia by Omega Peptides Australia from domestic stock, with same-day dispatch on orders placed before 12pm and an independent certificate of analysis for every batch. Commonly written as PT141, PT 141, bremelanotide or peptide 141, it is a melanocortin-4 receptor agonist studied for central melanocortin signalling.

PT-141, known by its non-proprietary name bremelanotide, is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (α-MSH). It is the C-terminal carboxylic acid metabolite of Melanotan II: the two molecules share the same acetylated norleucine start and the same lactam-bridged Asp-His-D-Phe-Arg-Trp-Lys ring, but where Melanotan II ends in an amide, bremelanotide ends in a free acid, written in full as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It was developed by Palatin Technologies after the company stopped work on Melanotan II in 2000. It is often written as PT141, PT 141 or pt-141 peptide, and its registered pharmaceutical form in the United States is branded Vyleesi.

PT-141 is studied chiefly for melanocortin signalling in central sexual-function circuits, for MC4R-mediated regulation of appetite and energy balance, and as a comparator in melanocortin receptor pharmacology. It acts as an agonist at MC1R, MC3R, MC4R and MC5R (not MC2R), with its research and clinical development centred on MC3R and MC4R in the hypothalamus, where receptor activation raises cyclic AMP and modulates downstream dopaminergic signalling.

Omega Peptides Australia supplies PT-141 as a high-purity (≥99% HPLC) COA-verified lyophilised powder in a sealed 10mg vial. Orders placed before 12pm are dispatched the same day from within Australia, and the batch Certificate of Analysis for every lot is published in our COA library so it can be checked before you order.

Key research areas

• Central sexual-function signalling The largest body of bremelanotide research concerns the melanocortin system's role in sexual response. Unlike vascular agents, it acts centrally: in rodent models MC4R activation in hypothalamic nuclei produces measurable changes in mating behaviour, and a clinical programme in hypoactive sexual desire disorder progressed through Phase 2 and Phase 3 and led to regulatory approval in the United States in 2019.
• Hypothalamic dopamine release Preclinical work in rats has shown that bremelanotide increases dopamine release in the medial preoptic area, a region that integrates sexual motivation. This finding gave a mechanistic link between melanocortin receptor activation and downstream dopaminergic signalling, and it is why the compound is used as a probe of the MC4R-dopamine interface in neuropharmacology.
• Appetite and energy balance MC4R is the central node through which leptin and pro-opiomelanocortin neurons suppress food intake. As a potent MC4R agonist, bremelanotide is used in rodent obesity models to study how receptor activation changes feeding, energy expenditure and body weight, and to compare against MC4R-selective compounds developed for genetic obesity syndromes.
• Melanocortin receptor pharmacology Because bremelanotide differs from Melanotan II by a single terminal group, the pair is a textbook example of how a small structural change shifts pharmacological profile. Side-by-side assays are used to characterise potency at each melanocortin subtype and to understand why the acid form was selected for MC4R-centred development.
• Haemorrhagic shock and ischaemia models Melanocortin agonists have been examined in preclinical models of haemorrhagic shock and ischaemia-reperfusion injury, where MC1R and MC3R signalling on immune and vascular cells is thought to dampen inflammatory cascades. Bremelanotide has appeared in this line of research as a broad-spectrum agonist alongside receptor-selective ligands.
• Route and pharmacokinetic research Early clinical work used an intranasal formulation; that route was set aside after transient blood-pressure increases were observed, and development moved to a subcutaneous autoinjector. The compound's plasma half-life of about 2.7 hours, and the way exposure varies with route, remain useful reference data for formulation studies of cyclic melanocortin peptides.

PT-141 in Australia

PT-141 is not registered on the Australian Register of Therapeutic Goods, so it is not stocked by Chemist Warehouse, Priceline or other pharmacies. In Australia it is supplied as a research-grade lyophilised vial by domestic research suppliers. Omega Peptides Australia holds PT-141 in stock within Australia and dispatches orders placed before 12pm the same business day on tracked domestic delivery, so material arrives in days rather than waiting on an international shipment and customs. Every batch is tested independently and its certificate is published in the COA library before the vial ships.

PT-141 is stocked in Australia as a lyophilised 10mg vial. Searches for PT-141 nasal spray in Australia refer to a delivery format prepared from the same lyophilised material. It is structurally related to Melanotan II, also held in domestic stock.

How PT-141 works

Native α-MSH is a linear thirteen-residue hormone that survives only minutes in circulation. Bremelanotide keeps just the His-D-Phe-Arg-Trp message sequence and locks it into a ring with a lactam bridge between aspartate and lysine, so the pharmacophore is presented in the conformation the receptor prefers. The norleucine and D-phenylalanine substitutions resist oxidation and proteolysis. In the body the amide of Melanotan II is hydrolysed to the free acid, which is bremelanotide, so the compound studied here is effectively the active metabolite of its parent. Its plasma half-life is roughly 2.7 hours, with a reported range of about 1.9 to 4.0 hours, considerably longer than the parent hormone.

The compound binds melanocortin receptors and activates the Gs-coupled cyclic AMP pathway. Its distinctive feature is where that happens: MC4R and MC3R in hypothalamic regions such as the paraventricular nucleus and medial preoptic area, where activation increases dopamine release and influences sexual-motivation and feeding circuits. This central mechanism is what separates PT-141 from vascular agents that act on smooth muscle, and its MC4R-centred profile is what separates it from the parent compound Melanotan II, which is studied mainly for MC1R-driven pigmentation. It is also distinct from Kisspeptin-10, which acts far upstream on the reproductive axis through the KISS1 receptor rather than through melanocortin signalling.

Specifications

Available sizes and pricing

PT-141 is supplied in a single 10mg research vial. It is frequently ordered with Melanotan II for parent-versus-metabolite comparisons, and with Kisspeptin-10 when a laboratory is mapping central and upstream reproductive signalling in the same series of experiments. Bacteriostatic water is sold separately in 3mL and 10mL vials.

• 10mg vial — $69.99 (about $7.00 per mg)

Quality and COA verification

Every batch of PT-141 is tested independently by Janoshik Analytical before release. HPLC measures purity against the ≥99% specification, and mass spectrometry confirms that the observed molecular mass matches bremelanotide rather than its amide parent Melanotan II, a distinction of only one mass unit that identity testing is designed to catch. A Certificate of Analysis is issued for each batch and published in our COA library, where the batch number printed on the vial can be matched to its report. The peptide is lyophilised to protect it from hydrolysis, sealed in a sterile vial under a crimped cap, and cushioned for domestic transit so it arrives in laboratory condition.

Frequently bought together

• Melanotan II (10mg) — $79.99, the amide parent compound for parent-versus-metabolite comparisons
• Kisspeptin-10 (10mg) — $79.99, the upstream reproductive-axis peptide for complementary signalling research
• Bacteriostatic Water (10mL) — $29.99, the recommended diluent for reconstitution
• Bacteriostatic Water (3mL) — $14.99, a smaller diluent vial for single-peptide work

Research guides

• Peptide storage guide: how to store lyophilised peptides properly
• COA testing explained: how research peptides are verified
• Peptide reconstitution calculator
• Certificates of Analysis library

Frequently asked questions

What is PT141?
PT141 is the shorthand for PT-141, the development code that Palatin Technologies gave to bremelanotide. The hyphen is often dropped in searches and listings, but PT141, PT 141 and PT-141 all refer to the same cyclic melanocortin peptide. It is the free-acid metabolite of Melanotan II and is studied for its activity at the MC4R and MC3R receptors in the hypothalamus.

What is PT-141?
PT-141, or bremelanotide, is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone. It is an agonist at MC1R, MC3R, MC4R and MC5R and is studied for central sexual-function signalling, appetite regulation and melanocortin receptor pharmacology. Its pharmaceutical form was approved in the United States in 2019. Omega Peptides Australia supplies it as a lyophilised 10mg research powder with a batch Certificate of Analysis, strictly for in-vitro laboratory use.

What is PT-141 also known as?
It is also written as PT141, PT 141, pt-141 peptide or pt141 peptide, and its non-proprietary drug name is bremelanotide, sometimes misspelled bremelanotid, bremelenotide or bremelanotine. The United States pharmaceutical product is branded Vyleesi. In older literature it may be described as the Melanotan II metabolite or the carboxylic-acid analogue of Melanotan II. Its CAS number is 189691-06-3.

How does PT-141 work?
It binds melanocortin receptors on the cell surface and activates the Gs-coupled cyclic AMP pathway. Its research profile is defined by MC4R and MC3R in hypothalamic regions such as the paraventricular nucleus and medial preoptic area, where activation increases dopamine release and modulates sexual-motivation and feeding circuits. This is a central mechanism, unlike vascular agents that act on smooth muscle. The plasma half-life is about 2.7 hours.

What does the research show about PT-141?
Preclinical rodent studies show that bremelanotide activates central MC4R pathways, increases dopamine release in the medial preoptic area and changes mating behaviour. A clinical programme in hypoactive sexual desire disorder progressed through Phase 2 and Phase 3 trials and supported United States approval in 2019. The intranasal route was abandoned after transient blood-pressure increases were seen. In obesity models it reduces food intake, consistent with MC4R agonism.

Can I buy PT-141 at Chemist Warehouse or a pharmacy in Australia?
No. Bremelanotide is listed as a prescription-only substance in Australia, but no bremelanotide product is registered on the Australian Register of Therapeutic Goods, so Chemist Warehouse, Priceline and other retail pharmacies do not stock it. The United States product Vyleesi is not registered by the TGA. The research-grade lyophilised PT-141 supplied here is a different product, a laboratory reagent for in-vitro use, not a medicine.

Can Australian compounding pharmacies supply PT-141?
Compounding pharmacies in Australia prepare medicines only for an individual patient on a practitioner's prescription and do not sell peptides to the public. Research suppliers such as Omega Peptides Australia supply the lyophilised research compound for laboratory use, which is a separate category from compounded medicines.

How do you reconstitute PT-141?
Use bacteriostatic water. Draw the required volume into a sterile syringe, pierce the vial septum and let the water run slowly down the inside wall of the vial rather than directly onto the powder. Swirl gently until the solution is clear; do not shake, because agitation can denature the peptide. Refrigerate the reconstituted vial at 2–8°C and use it within 28 days. Our reconstitution calculator will give you the resulting concentration.

How should PT-141 be stored?
Store the lyophilised vial at 2–8°C for short-term use or at −20°C for long-term storage, protected from light and moisture, and avoid repeated freeze-thaw cycles. After reconstitution keep the solution refrigerated at 2–8°C and use it within 28 days. Lyophilised PT-141 tolerates ambient temperatures during domestic transit, so no cold chain is required for delivery.

Where can I buy PT-141 in Australia?
Omega Peptides Australia holds PT-141 in domestic stock and ships from within Australia, avoiding international delays and customs uncertainty. Orders placed before 12pm are dispatched the same day, every batch carries an independent Certificate of Analysis, and you can browse the full range in our research peptides collection. We are a research supplier only and do not supply PT-141 for human use.

What does PT-141 cost in Australia?
A 10mg vial of PT-141 costs $69.99, which works out to about $7.00 per mg. That is $10 less than the parent compound Melanotan II at $79.99 per 10mg vial. Prices are in Australian dollars and include the independent Janoshik Analytical testing and the batch Certificate of Analysis.

How do I get PT-141 online in Australia?
Select the 10mg vial on this page, add it to your cart and check out. Orders placed before 12pm are dispatched the same business day from our Australian facility with tracked domestic shipping. Packaging is plain and discreet, the vial is cushioned for transit, and a tracking number is emailed once the parcel is collected. The batch COA can be checked in the COA library at any time.

Is PT-141 legal in Australia?
Omega Peptides Australia supplies PT-141 strictly for lawful in-vitro laboratory research. It is not approved by the TGA for human or veterinary use and is not sold as a medicine or supplement. Purchasers are responsible for ensuring their intended use complies with all applicable laws.

What is the difference between PT-141 and Melanotan II?
Both are cyclic melanocortin agonists with the same lactam-bridged ring, and both activate MC1R, MC3R, MC4R and MC5R. The difference is the C-terminus: Melanotan II ends in an amide and PT-141 in a carboxylic acid, and PT-141 is the metabolite formed from Melanotan II. In practice Melanotan II is studied mainly for MC1R-driven pigmentation, while PT-141 was selected and developed for MC4R-centred research into central sexual-function signalling.

Is PT-141 available in Australia?
Yes, as a research-grade lyophilised peptide from domestic suppliers. It is not a registered medicine in Australia. Omega Peptides Australia holds PT-141 10mg in Australian stock, COA verified, with same-day dispatch before 12pm.

Where can I buy PT141 in Australia?
From an Australian research peptide supplier holding domestic stock. Omega Peptides Australia ships PT-141 from within Australia on tracked delivery.

⚠ For in-vitro research and laboratory use only. Not for human or veterinary use.