Melanotan II

Overview

Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH). Developed at the University of Arizona in the 1990s, it was designed as a more potent and longer-acting alternative to the naturally occurring α-MSH for research into melanocortin receptor pharmacology.

As a non-selective melanocortin receptor agonist, Melanotan II binds to multiple melanocortin receptor subtypes (MC1R, MC3R, MC4R, and MC5R), each mediating different physiological responses. This broad receptor binding profile has made it a valuable research tool for studying the diverse functions of the melanocortin system.

The cyclic structure of Melanotan II confers enhanced stability and resistance to enzymatic degradation compared to linear peptides, contributing to its relatively long duration of action in research settings.

Chemical Profile

Mechanism of Action

Melanotan II functions as a non-selective melanocortin receptor agonist, with its primary mechanism involving binding to and activation of melanocortin receptors (MCRs) across multiple subtypes. The cyclic lactam bridge structure provides conformational rigidity that enhances receptor binding affinity compared to the linear native α-MSH.

At MC1R (predominantly expressed in melanocytes), activation stimulates the cAMP/PKA signaling pathway, leading to upregulation of tyrosinase and related enzymes involved in melanogenesis — the production of melanin pigment. At MC3R and MC4R (expressed in the hypothalamus), activation modulates appetite regulation, energy homeostasis, and sexual function through central nervous system pathways.

The peptide's interaction with MC4R in the paraventricular nucleus of the hypothalamus triggers downstream signaling cascades involving oxytocin and other neuropeptides, which mediate its effects on sexual arousal pathways studied in preclinical models.

Research Applications

• Melanogenesis and skin pigmentation mechanisms
• MC1R/MC3R/MC4R/MC5R receptor pharmacology
• Energy homeostasis and appetite regulation
• Sexual function and arousal pathway research
• Melanocortin receptor binding studies
• UV protection mechanism research

Handling & Reconstitution

1. 1Allow the vial and sterile water to reach room temperature (15–25°C).
2. 2Using a sterile syringe, withdraw the appropriate volume of sterile water.
3. 3Inject the water slowly along the inside wall of the vial — do not spray directly onto the powder.
4. 4Gently swirl the vial until the powder is fully dissolved. Do not shake vigorously.
5. 5Once reconstituted, store at 2°C – 8°C. Protect from light.
6. 6Use within 28 days after reconstitution.
7. 7Do not freeze reconstituted solution.