Melanotan II (Cyclic Melanocortin Agonist)

Melanotan II is a cyclic synthetic analog of alpha-MSH. Unlike the linear Melanotan I, it is a shorter seven-residue cyclic peptide built on the alpha-MSH(4-10) core, a ring structure that increases its stability and its potency across several melanocortin receptors. It carries CAS number 121062-08-6 and the molecular formula C50H69N15O9, with a molecular weight of 1024.2 g/mol.

Because of its broad melanocortin activity, it is a frequently studied tool compound in receptor research. It is supplied as a lyophilized powder for laboratory reconstitution.

Melanotan II was developed from melanocortin research as a more compact, cyclic alternative to the linear alpha-MSH analogs. A 2003 study by Ter Laak and colleagues in the European Journal of Pharmacology examined its peripheral effects in a model system (PubMed 12591111).

More recent neuroscience research has used it as a melanocortin agonist tool. A 2021 study by McMillan and colleagues in Experimental Physiology reported on its physiological effects (PubMed 33332767), and a 2022 study by Eliason and colleagues in Neuropeptides used targeted microinjection to study its central activity (PubMed 36155088). This research is preclinical.

Melanotan II is studied as a non-selective melanocortin receptor agonist, with activity across receptors including MC1R, MC3R, and MC4R. The MC1R activity connects it to melanin research in skin models, while MC4R activity in the central nervous system connects it to appetite and other signaling studied in animal models.

The metabolite PT-141 is derived from Melanotan II and is studied for a narrower central activity profile. For current findings, search PubMed directly.

Lyophilized Melanotan II is generally stored at -20°C for long-term holding, with stability reported around 24 months. Refrigeration at 2°C to 8°C suits shorter windows, away from light and moisture.

The lot-specific Certificate of Analysis is the authoritative reference for a given batch.

Reconstitution means returning a lyophilized compound to solution. This page gives no preparation procedure: solvent, concentration and handling steps belong to the methodology of the study being reproduced, not to a compound reference. Melanotan II is handled as aqueous-soluble material.

Lyophilized material is hygroscopic, so a sealed container is allowed to reach ambient temperature before it is opened. Solubility and water-content figures for a given lot appear on its Certificate of Analysis.

Identity and purity of research-grade Melanotan II are established analytically, by HPLC with mass spectrometric confirmation of the expected mass. Verified purity is documented per lot on the Certificate of Analysis.

Check HPLC purity, mass-spec identity, and net peptide content on the Certificate of Analysis. peptides.com publishes lot-specific lab reports for verification.

Melanotan II is grouped with the melanocortin receptor agonists:

• Melanotan I.
  The linear alpha-MSH analog. 
• PT-141.
  A melanocortin agonist derived from Melanotan II. 
• GHK-Cu.
  A separate skin-context research peptide.

Ter Laak MP, Brakkee JH, et al. (2003). The potent melanocortin receptor agonist melanotan-II promotes peripheral effects. European Journal of Pharmacology.
PubMed 12591111

McMillan TR, Forster MAM, et al. (2021). Melanotan II, a melanocortin agonist, and impaired thermoregulation. Experimental Physiology.
PubMed 33332767

Eliason NL, Martin L, et al. (2022). Melanocortin receptor agonist melanotan-II microinjected in the nucleus accumbens. Neuropeptides.
PubMed 36155088

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