Chemical Name：Melanotan II (MT-II)

CAS:121062-08-6

Synonyms：Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH?, Melanotan 2, MT-2

Molecular Formula：C??H??N??O??

Molecular Weight：1024.2 g/mol

Appearance：White to off-white powder

Solubility：Soluble in water (>10 mg/mL), slightly soluble in organic solvents (e.g., DMSO)

Stability：Stable at room temperature when lyophilized; aqueous solutions may degrade over time (store at -20°C)

Peptide Sequence Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH? (Cyclic heptapeptide with a lactam bridge between Asp and Lys)

Biological Function:Synthetic analog of α-MSH (melanocyte-stimulating hormone); non-selective agonist of melanocortin receptors (MC1R, MC3R, MC4R, MC5R). Promotes melanogenesis, libido enhancement, and potential appetite suppression.

Primary Uses:Research compound (originally studied for sunless tanning, erectile dysfunction, and weight loss). Not FDA-approved; sold as an unregulated peptide.

Half-Life ~2–3 hours (subcutaneous administration)

Side Effects:Nausea, facial flushing, appetite suppression, spontaneous erections (in males), darkening of existing moles/freckles.

Structure: Cyclic peptide with a modified amino acid sequence (D-Phe enhances receptor binding).

Mechanism: Activates melanocortin receptors, stimulating melanin production and modulating sexual appetite/metabolism.

Legal Status: Unapproved for medical use; classified as a research chemical in most countries