Melanotan II

Melanotan II (10mg) — Cyclic Melanocortin Agonist Research Peptide

Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (α-MSH), the endogenous pigment-regulating hormone cleaved from pro-opiomelanocortin. It was synthesised at the University of Arizona in the 1980s during a programme to build more stable and more potent α-MSH analogues. The molecule keeps the core His-D-Phe-Arg-Trp message sequence of the parent hormone, replaces methionine with norleucine, and closes a lactam bridge between an aspartate and a lysine residue so that the active loop is locked in a ring: written in full, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. It is often written as MT2, MT-2, MTII, melanotan 2 or melanotan ii, and is sometimes simply called the melanotan peptide.

Melanotan II is studied in three main directions: melanogenesis and pigmentation biology, melanocortin-driven sexual-function signalling (it is the parent compound from which bremelanotide was derived), and the central regulation of appetite and energy balance. At the receptor level it acts as a non-selective agonist across the melanocortin family, binding MC1R on melanocytes as well as the centrally expressed MC3R and MC4R, and driving adenylyl cyclase and cyclic AMP signalling in the target cell.

Omega Peptides Australia supplies Melanotan II 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 can be checked in our COA library before you order.

Key research areas

• Melanogenesis and pigmentation The best-characterised action of Melanotan II is at MC1R on melanocytes. Receptor activation raises intracellular cAMP, up-regulates the transcription factor MITF and increases tyrosinase activity, shifting melanin synthesis towards eumelanin. This pathway has been examined in cultured melanocytes, in rodent and other preclinical pigmentation models, and in early clinical investigations of the compound in the 1990s.
• Melanocortin signalling in sexual function Research into α-MSH analogues in this area dates back to observations in rats in the 1960s. Melanotan II was later shown in preclinical models and in early human investigations to produce erectile responses through a central, MC4R-mediated mechanism rather than a vascular one. That finding is what led to the development of bremelanotide (PT-141) as a separate compound.
• Appetite and energy balance MC4R sits downstream of leptin and pro-opiomelanocortin neurons in the hypothalamus. In rodent models, central administration of Melanotan II reduces food intake and body weight, and the compound is used as a reference agonist when the leptin-POMC-MC4R axis is investigated in obesity and cachexia research.
• Photoprotection research Eumelanin absorbs and scatters ultraviolet radiation, so agonists that shift pigment production towards eumelanin have been studied for their capacity to change the skin's baseline response to UV exposure in research models. Comparative work often sets Melanotan II beside the linear analogue afamelanotide (Melanotan I).
• Inflammation and ischaemia models Melanocortin receptor agonists have been investigated in preclinical models of ischaemia-reperfusion, inflammation and haemorrhagic shock, with proposed mechanisms involving MC1R and MC3R signalling in immune and vascular cells. Melanotan II appears in this literature mainly as a broad-spectrum comparator to receptor-selective ligands.
• Receptor pharmacology tool compound Because it is potent, metabolically stable and active at MC1R, MC3R, MC4R and MC5R, Melanotan II is one of the most widely used reference ligands in melanocortin receptor binding and functional assays. It is routinely included as a positive control when new selective agonists and antagonists are characterised.

How Melanotan II works

Native α-MSH is a linear thirteen-residue peptide with a plasma half-life of only a few minutes, because circulating proteases quickly cleave it and its methionine residue is prone to oxidation. Melanotan II was designed to remove those weaknesses. The sequence is trimmed to the core message, the L-phenylalanine is replaced by D-phenylalanine to resist enzymatic cleavage, methionine is replaced by norleucine to stop oxidation, and the side chains of aspartate and lysine are joined in a lactam bridge. The result is a compact ring that holds the His-D-Phe-Arg-Trp pharmacophore in the conformation the receptor prefers, which is why Melanotan II binds with far greater potency and persists far longer than the parent hormone.

Once bound, it activates the receptor's Gs-coupled pathway, raising cAMP and driving downstream effects that depend on which receptor and which cell type are involved: MC1R activation on melanocytes increases eumelanin synthesis, while MC3R and MC4R activation in hypothalamic neurons influences appetite, energy expenditure and sexual-function circuits. This lack of selectivity is the key difference from Melanotan I (afamelanotide), a linear analogue that favours MC1R and has a half-life of roughly thirty minutes, and from bremelanotide, which is the C-terminal carboxylic acid metabolite of Melanotan II and is used for its MC3R and MC4R activity rather than pigmentation.

Specifications

Available sizes and pricing

Melanotan II is supplied in a single 10mg research vial. If you also need the diluent and consumables for reconstitution, the Melanotan II Starter Kit bundles the same vial with bacteriostatic water, syringes and swabs at a lower combined price, and the Retatrutide + Melanotan 2 Starter Bundle pairs it with a metabolic research peptide.

• 10mg vial — $79.99 (about $8.00 per mg)

Quality and COA verification

Every batch of Melanotan II is sent to Janoshik Analytical for independent third-party testing before it is released for sale. HPLC establishes purity against the ≥99% specification, and mass spectrometry confirms that the molecular mass matches the expected value for the compound, so both identity and purity are verified rather than assumed. A Certificate of Analysis is issued for each batch and published in our COA library, where the batch number on your vial can be matched to its report. The peptide is lyophilised for stability and sealed in a sterile vial under a crimped cap, then packed with protective cushioning for domestic transit so that it arrives in the same condition it left the laboratory.

Frequently bought together

• Melanotan I (10mg) — $69.99, the linear MC1R-preferring analogue for side-by-side selectivity comparisons
• Melanotan II Starter Kit — $109.99, the same vial packed with bacteriostatic water, syringes and swabs
• PT-141 (10mg) — $69.99, the bremelanotide metabolite for MC4R-focused research
• Bacteriostatic Water (10mL) — $29.99, the recommended diluent for reconstitution

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 MT2?
MT2 is the common shorthand for Melanotan II, a synthetic cyclic analogue of the pigment hormone α-MSH. The name distinguishes it from MT1 (Melanotan I, afamelanotide), the linear analogue developed in the same University of Arizona programme. In research listings the two are frequently confused, so check the sequence: MT2 is the seven-residue lactam-bridged ring, MT1 is the thirteen-residue linear peptide.

What is Melanotan II?
Melanotan II is a synthetic cyclic heptapeptide derived from alpha-melanocyte-stimulating hormone. It is a non-selective melanocortin receptor agonist that activates MC1R, MC3R, MC4R and MC5R, and it is studied in pigmentation, sexual-function and appetite research. 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 Melanotan II also known as?
It is also written as MT2, MT-2, MTII, melanotan 2, melanotan ii or melanotan-2, and is sometimes called the melanotan peptide or the cyclic α-MSH analogue. Common misspellings include melanotin, melanotam and melatonan (the last is often confused with melatonin, an unrelated hormone). Its chemical descriptor is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 and its CAS number is 121062-08-6.

How does Melanotan II work?
It binds melanocortin receptors on the cell surface and activates the Gs-coupled cAMP pathway. At MC1R on melanocytes this raises MITF and tyrosinase activity, increasing eumelanin synthesis. At MC3R and MC4R in the hypothalamus it modulates appetite and sexual-function circuits. Its cyclic lactam structure, D-phenylalanine and norleucine substitutions make it far more potent and more resistant to enzymatic breakdown than native α-MSH.

What does the research show about Melanotan II?
In cultured melanocytes and preclinical models Melanotan II reliably increases eumelanin production through MC1R. Early clinical investigations in the 1990s reported increased skin pigmentation and, unexpectedly, erectile responses in male volunteers, an observation that led to the development of bremelanotide. Rodent studies show that central MC4R activation by the compound reduces food intake. It remains a standard reference agonist in melanocortin receptor pharmacology.

Can I buy Melanotan II at Chemist Warehouse or a pharmacy in Australia?
No. The TGA classifies Melanotan II as a prescription-only substance, but there are no products containing it on the Australian Register of Therapeutic Goods, so Chemist Warehouse, Priceline and other retail pharmacies do not stock it. The TGA has also issued repeated warnings about tanning products containing melanotan. The lyophilised research-grade compound supplied here is a laboratory reagent for in-vitro use, not a medicine.

Can Australian compounding pharmacies supply Melanotan II?
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 Melanotan II?
Use bacteriostatic water. Draw the required volume into a sterile syringe, insert through the vial septum and let the water run slowly down the inside wall of the vial rather than onto the powder. Swirl gently until the solution is clear; never 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 work out the concentration for you.

How should Melanotan II be stored?
Keep the lyophilised vial refrigerated at 2–8°C for short-term storage or frozen at −20°C for long-term storage, protected from light and moisture. Avoid repeated freeze-thaw cycles. Once reconstituted, store the solution at 2–8°C and use it within 28 days. Lyophilised Melanotan II is stable for transit at ambient temperature, so no cold chain is needed for domestic delivery.

Where can I buy Melanotan II in Australia?
Omega Peptides Australia holds Melanotan II in domestic stock and ships from within Australia, so there are no international delays or customs uncertainty. Orders placed before 12pm are dispatched the same day, every batch carries an independent COA, and you can browse the full range in our research peptides collection. We are a research supplier only and do not supply Melanotan II for human use.

What does Melanotan II cost in Australia?
A 10mg vial of Melanotan II costs $79.99, which works out to about $8.00 per mg. The Melanotan II Starter Kit, which adds bacteriostatic water, syringes and alcohol swabs to the same vial, is $109.99. All prices are in Australian dollars and include the independent Janoshik Analytical testing and Certificate of Analysis for the batch.

How do I get Melanotan II 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, and the vial is cushioned for transit. A tracking number is emailed once the parcel is collected, and the batch COA is available in the COA library.

Is Melanotan II legal in Australia?
Omega Peptides Australia supplies Melanotan II 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 Melanotan II and Melanotan I?
Both are α-MSH analogues from the same research programme, but they differ in structure and selectivity. Melanotan I (afamelanotide) is a linear thirteen-residue peptide that favours MC1R, has a half-life of about thirty minutes, and is the active ingredient in a registered implant medicine. Melanotan II is a cyclic seven-residue peptide that activates MC1R, MC3R, MC4R and MC5R, which is why it appears in appetite and sexual-function research as well as pigmentation studies.

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