Melanotan II
A synthetic cyclic heptapeptide (cyclic lactam, 7 residues) studied as a conformationally constrained reference ligand in class A GPCR binding, structure-activity chemistry, and structural-biology research.
View MT-2 in the storeQuick answers
What is Melanotan II?
Melanotan II is a synthetic cyclic heptapeptide (cyclic lactam, 7 residues) studied as a conformationally constrained reference ligand in class A GPCR binding, structure-activity chemistry, and structural-biology research. It is a synthetic cyclic heptapeptide (cyclic lactam) of 7 amino acids with a molecular weight of 1,024.18 g/mol and the formula C50H69N15O9.
How much published research cites Melanotan II?
The Luvaminos Melanotan II record cites 22 published references, dated 1987 to 2025. Each is listed on this page with a link to its source.
Does Luvaminos test Melanotan II, and where is the certificate?
Yes. Every Melanotan II lot Luvaminos sells is tested by Freedom Diagnostics Testing, PLLC, an independent laboratory. The current 10 mg lot, MTII-10-001, measured 99.76% purity by HPLC and a net content of 13.92 mg, tested September 4, 2026. Its certificate is published at luvaminos.com/coa/MTII-10-001.
What modifications does Melanotan II carry?
Melanotan II: N-terminal acetylation; C-terminal amide; cyclic lactam bridge between the Asp side-chain γ-carboxyl and the Lys side-chain ε-amino group; contains norleucine (Nle) in place of methionine and D-phenylalanine in place of L-phenylalanine.
How is Melanotan II powder stored?
Sealed Melanotan II powder: -20°C or colder for long-term storage; protected from light and moisture in a desiccated environment. Avoid repeated freeze-thaw cycles.
Molecular Profile
- Type
- Synthetic cyclic heptapeptide (cyclic lactam)
- Molecular formula
- C50H69N15O9
- Molecular weight
- 1,024.18 g/mol
- CAS number
- 121062-08-6
- Amino acids
- 7
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
- Modification
- N-terminal acetylation; C-terminal amide; cyclic lactam bridge between the Asp side-chain γ-carboxyl and the Lys side-chain ε-amino group; contains norleucine (Nle) in place of methionine and D-phenylalanine in place of L-phenylalanine.
Mechanism & Target Class
Melanotan II is a conformationally constrained cyclic lactam heptapeptide. It retains the conserved His-Phe-Arg-Trp core motif, with three engineered modifications relative to the parent linear sequence: substitution of methionine by norleucine, inversion of L-phenylalanine to D-phenylalanine, and a side-chain-to-side-chain lactam bridge (Asp–Lys) that locks the backbone into a defined turn conformation. These changes are associated with reduced susceptibility to enzymatic cleavage in vitro and constrain the bioactive conformation. The constrained scaffold is widely used as a reference ligand for characterizing the binding and selectivity profile of class A (rhodopsin-like) G-protein-coupled receptors in radioligand and structural-biology studies.
Storage & Handling
- Lyophilized
- -20°C or colder for long-term storage; protected from light and moisture in a desiccated environment.
- Handling
- Avoid repeated freeze-thaw cycles; Water-soluble; handle as a research-use-only laboratory reagent following standard peptide-handling practice.
Primary Database
References (22)
Reviews
1Habbema L, Halk AB, Neumann M, Bergman W (2017). International Journal of Dermatology
- 2
King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H (2007). Current Topics in Medicinal Chemistry
- 3
Hadley ME, Dorr RT (2006). Peptides
- 4
Fung S, Hruby VJ (2005). Current Opinion in Chemical Biology
- 5
Adan RA, Gispen WH (1997). Peptides
- 6
Rouzaud F, Kadekaro AL, Abdel-Malek ZA, Hearing VJ (2005). Mutat Res
- 7
Hadley ME (2005). Peptides
- 8
Böhm M, Robert C, Malhotra S, Clément K, Farooqi S (2025). J Eur Acad Dermatol Venereol
Clinical
9Wessells H, Gralnek D, Dorr R, Hruby VJ, Hadley ME, Levine N (2000). Urology
- 10
Wessells H, Levine N, Hadley ME, et al. (2000). Int J Impot Res
Primary research
11Heyder NA, Kleinau G, Speck D, Schmidt A, Paisdzior S, et al. (2021). Cell Research
- 12
Yu J, Gimenez LE, Hernandez CC, Cone RD, Stevens RC, et al. (2020). Science
- 13
Martin C, Gimenez LE, Williams SY, Cone RD, Stevens RC, Ballet S, et al. (2020). Journal of Medicinal Chemistry
- 14
Nelson ME, Bryant SM, Aks SE (2012). Clinical Toxicology
- 15
Grieco P, Cai M, Han G, Trivedi D, Campiglia P, Novellino E, Hruby VJ (2007). Peptides
- 16
Hruby VJ, Lu D, Sharma SD, Castrucci AL, Kesterson RA, al-Obeidi FA, Hadley ME, Cone RD (1995). Journal of Medicinal Chemistry
- 17
Al-Obeidi F, Castrucci AM, Hadley ME, Hruby VJ (1989). Journal of Medicinal Chemistry
- 18
Al-Obeidi F, Hadley ME, Pettitt BM, Hruby VJ (1989). Journal of the American Chemical Society
- 19
Hruby VJ, Wilkes BC, Hadley ME, Al-Obeidi F, Sawyer TK, et al. (1987). Journal of Medicinal Chemistry
- 20
Van der Ploeg LH, Martin WJ, Howard AD, Nargund RP, Austin CP, et al. (2002). Proc Natl Acad Sci U S A
- 21
Vemulapalli R, Kurowski S, Salisbury B, Parker E, Davis H (2001). Br J Pharmacol
- 22
Eliason NL, Martin L, Low MJ, Sharpe AL (2022). Neuropeptides
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