Melanotan II 10mg

Melanotan II is a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone (α-MSH) with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂. Its cyclic structure gives it higher metabolic stability and broader melanocortin receptor affinity (MC1R, MC3R, MC4R, MC5R) compared to the linear Melanotan I. In preclinical research, Melanotan II has been studied for melanogenesis and skin pigmentation pathways, MC4R-mediated energy homeostasis and appetite regulation, MC3R/MC5R receptor pharmacology, and sexual function and arousal research models. CAS: 121062-08-6; MW: 1024.18 Da. Supplied at 99.1% HPLC purity.

Legal status: Melanotan II is legal to purchase in Australia for legitimate laboratory research purposes. It is not listed as a scheduled substance under the Poisons Standard when sold for research use only. Purchasers must be 18+. Not for human consumption, therapeutic, cosmetic, or veterinary use — important note: Melanotan II is not approved for any therapeutic use in Australia and must not be represented as such. Quality: Batch PW-260309, independently verified at 99.1% HPLC purity. COA includes: HPLC purity %, mass spectrometry identity confirmation, and sterility screening. Full COA in our COA Library.

Reconstitution: Using a 31G syringe, draw 1–2mL of bacteriostatic water. Inject slowly down the inside glass wall of the vial — never directly onto the lyophilised cake. Gently swirl until fully dissolved. Solution should be clear and colourless. Common concentration: 1mL BAC water per 10mg = 10mg/mL. Storage: Lyophilised — store at −20°C, protected from light and moisture, for 12–24 months. Reconstituted — refrigerate at 2–8°C and use within 4 weeks. Melanotan II is light-sensitive in solution — wrap vial in foil or keep in a dark container after reconstitution.

While both are α-MSH analogues, they have important structural and pharmacological differences. Melanotan I is a linear peptide (MW 1646.87 Da) with selective MC1R affinity — making it a more targeted tool for pigmentation and photoprotection research. Melanotan II is a cyclic peptide (MW 1024.18 Da) with broader melanocortin receptor affinity (MC1R, MC3R, MC4R, MC5R), which means it engages a wider range of physiological pathways. For research specifically targeting pigmentation: Melanotan I is more selective. For broader melanocortin receptor pharmacology research: Melanotan II offers more receptor coverage. They are not interchangeable research tools.

Melanotan II has a molecular weight of 1024.18 Da and the CAS number 121062-08-6. Its molecular formula is C₅₀H₆₉N₁₅O₉. The compound is a heptapeptide in cyclic lactam form: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂, where the cycle is formed by a lactam bond between the Asp side chain carboxyl and the Lys side chain amine. This cyclic structure contributes to its high metabolic stability and broad melanocortin receptor binding profile. Identity is confirmed in Batch PW-260309 via mass spectrometry as documented in the COA. Not for human consumption — for research use only.

Melanotan II is a non-selective melanocortin receptor agonist that binds to MC1R, MC3R, MC4R, and MC5R with nanomolar affinity. Reported Ki values: MC1R ~0.21 nM; MC3R ~0.66 nM; MC4R ~0.53 nM; MC5R ~1.7 nM. This broad receptor profile is in contrast to Melanotan I (afamelanotide), which has much greater selectivity for MC1R. The MC4R binding of Melanotan II is the basis for its research in energy homeostasis, appetite, and MC4R pharmacology. MC5R binding is associated with exocrine gland function research models. Not for human consumption — for research use only.

The full sequence of Melanotan II is: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂. This is a 7-residue cyclic lactam peptide. The N-terminus is acetylated (Ac-) and the C-terminus is amidated (-NH₂). The ring is formed via a lactam bond between the β-carboxyl of Asp and the ε-amine of Lys. Key modifications relative to the α-MSH core sequence include: Nle (norleucine) replacing Met for oxidative stability, D-Phe replacing L-Phe for enhanced receptor binding affinity, and the lactam cyclisation that rigidifies the pharmacophore and dramatically improves metabolic stability. Not for human consumption — for research use only.

Melanotan I is a linear peptide — its backbone runs from N-terminus to C-terminus without forming a ring. Melanotan II is a cyclic lactam peptide — a covalent bond between the Asp (position 3) side chain carboxyl and the Lys (position 8) side chain amine closes the peptide into a ring, constraining the conformation of the central pharmacophore (His-D-Phe-Arg-Trp). This conformational constraint does two things: it pre-organises the binding epitope into an active conformation, increasing receptor binding affinity across multiple MCR subtypes; and it dramatically reduces susceptibility to proteolytic cleavage relative to linear peptides. As a result, Melanotan II is significantly more potent and metabolically stable than Melanotan I on a molar basis. Not for human consumption — for research use only.

MC4R (melanocortin-4 receptor) is expressed in the hypothalamus and other CNS regions and is one of the most studied GPCRs in metabolic and neuroscience research. Key research applications involving MC4R agonism (via Melanotan II or selective MC4R agonists) include: energy homeostasis and obesity research — MC4R is a central regulator of food intake and body weight; sexual function and erectile function research in rodent models; gut motility and gastric emptying research; and autonomic nervous system regulation. MC4R loss-of-function mutations are associated with severe hereditary obesity, making the receptor a major target in metabolic disease research. Not for human consumption — for research use only.

Melanotan II is freely soluble in water and in dilute aqueous acid. It is typically soluble in bacteriostatic water at concentrations up to 10mg/mL and above, making reconstitution straightforward. It is also soluble in DMSO for concentrated stock preparation in cell-based assays. The compound has moderate solubility in ethanol. For in-vitro receptor binding and functional assays, aqueous reconstitution with BAC water (available at /products/bac-water-10ml) followed by dilution in assay buffer is the standard approach. The lyophilised form is stable and reconstitutes readily without requiring sonication or heating. Not for human consumption — for research use only.

No — 4 weeks refrigerated (2–8°C) is the recommended maximum for reconstituted Melanotan II. Beyond this period, peptide degradation and potential loss of receptor activity cannot be excluded. The benzyl alcohol in BAC water maintains bacteriostatic conditions, but does not prevent chemical degradation of the peptide backbone over extended periods. For long-term storage, the lyophilised powder at −20°C is the correct format — the lyophilised form retains activity for up to 12–24 months. If your research requires smaller, more frequent reconstitutions, consider using 1mL BAC water per vial and consuming within the 4-week window rather than storing large reconstituted volumes. Not for human consumption — for research use only.

The current batch is PW-260309. The Certificate of Analysis is publicly available in our COA Library via the COA link on this product page. The COA documents: HPLC purity (99.1%), mass spectrometry identity confirmation (MW 1024.18 Da, CAS 121062-08-6), sterility screening results, and manufacturing provenance. For a direct email copy, contact info@auspeptidewarehouse.com.au with your order number or the batch reference PW-260309. Not for human consumption — for research use only.