Melanotan II

Melanotan II is a synthetic cyclic lactam analog of α-MSH (cyclo[Nle4, Asp5, D-Phe7, Lys10]-α-MSH-(4-10)). The cyclic structure confers significantly greater metabolic stability and potency than linear analogs. Unlike Melanotan I, Melanotan II is a non-selective melanocortin receptor agonist with substantial activity at MC1R, MC3R, MC4R, and MC5R.

Its broad receptor profile — particularly at MC4R, which is expressed in the hypothalamus, brainstem, and spinal cord — produces effects beyond melanogenesis, including appetite suppression, sexual arousal (erection in males via spinal MC4R), and increased energy expenditure. The MC4R-activating properties were the basis for development of PT-141 (bremelanotide), which retains the MC4R activity without the tanning effect. Melanotan II is studied in melanocortin pharmacology, sexual function research, and feeding behavior models.

• Broad melanocortin receptor (MC1R, MC3R, MC4R, MC5R) pharmacology
• UV-independent melanogenesis and eumelanin production research
• MC4R-mediated appetite suppression and energy expenditure studies
• Sexual arousal and spinal MC4R pharmacology models
• Comparison with Melanotan I, PT-141, and alpha-MSH receptor selectivity
• Feeding behavior, obesity, and hypothalamic melanocortin research

Dose levels referenced by the MVLabs peptide calculator, shown for research reference only:

Melanocortin agonist. Start low (nausea/flush). Load before sun exposure.

Research reference only — not dosing guidance for human use. Use the calculator for other vials or volumes.

Supplied as a lyophilized powder. Store at 2–8 °C on receipt; protect from heat, light and moisture, and avoid excessive agitation. If reconstitution is required for laboratory work, use sterile technique — bacteriostatic water, or 0.6% acetic acid for low-solubility peptides. Protocols vary by research application.