Melanotan 2
A synthetic melanocortin receptor agonist studied for effects on melanogenesis, skin pigmentation, appetite, and sexual response in research models.
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What is Melanotan 2?
Melanotan 2 (MT-II) is a synthetic cyclic heptapeptide and analog of α-melanocyte stimulating hormone (α-MSH). The peptide was developed at the University of Arizona in the late 1980s and early 1990s as part of research aimed at producing a synthetic compound that could induce skin pigmentation as a potential protective measure against UV-induced skin damage. The structural modifications from native α-MSH — including cyclization, N-terminal acetylation, and incorporation of non-natural amino acids — confer enhanced metabolic stability, increased potency, and broad melanocortin receptor agonism.
Melanotan 2 is notable in research as one of the most extensively studied non-selective melanocortin receptor agonists. The peptide produces effects across multiple melanocortin receptor subtypes (MC1R, MC3R, MC4R, and MC5R), resulting in a broad pharmacological profile including effects on melanogenesis, sexual response, appetite regulation, and inflammatory responses. Research interest in the various effects led to development of more selective derivatives, including PT-141 (bremelanotide) which retains the sexual response effects while minimizing the pigmentation effects.
Mechanism of action
Melanotan 2’s mechanisms of action have been investigated across multiple pathways:
- Non-selective melanocortin receptor activation: The peptide activates all five melanocortin receptor subtypes (MC1R through MC5R), producing the broad effect profile that distinguishes it from more selective derivatives.
- MC1R-mediated melanogenesis: Activation of MC1R on melanocytes stimulates the production of eumelanin (dark pigment) over pheomelanin, producing the skin darkening effect that originally drove research interest in the compound.
- MC3R/MC4R central effects: Activation of these receptors in the central nervous system produces effects on sexual response, appetite suppression, and certain behavioral parameters, with MC4R activation particularly associated with effects on food intake.
- MC5R peripheral effects: Activation of MC5R produces effects on exocrine gland function and inflammatory responses in peripheral tissues.
- Cyclic structure and stability: The cyclic structure protects against enzymatic degradation, providing the metabolic stability necessary for biological activity following peripheral administration.
These pathways are characterized in both preclinical models and limited clinical research.
Research applications
Melanotan 2 has been investigated across several research domains, with the most active areas including:
- Skin pigmentation research: The original research focus examined effects on skin pigmentation through MC1R-mediated melanogenesis, with early clinical research suggesting potential protective effects against UV damage in populations with skin types vulnerable to UV-induced damage.
- Sexual function research: Unexpected sexual response effects observed in early clinical trials drove additional research and ultimately led to development of PT-141 (bremelanotide) as a more selective compound for these effects.
- Appetite and metabolic research: Studies have examined effects on food intake and body weight regulation through MC4R-mediated pathways, contributing to understanding of melanocortin signaling in energy balance.
- Inflammatory and immune research: Research has examined effects on inflammatory responses mediated through MC1R and MC5R, with applications in models of inflammatory skin conditions and other inflammatory processes.
- Melanocortin receptor pharmacology research: Melanotan 2 serves as a research tool for studying the broad effects of non-selective melanocortin receptor activation, contributing to characterization of each receptor subtype’s contributions to physiological function.
This compound is intended for laboratory research use only. It has not been approved for human therapeutic use by any regulatory agency.
Storage & reconstitution
In its lyophilized form, Melanotan 2 tolerates ambient temperatures during shipping but should be stored long-term at -20°C, protected from light. Properly stored lyophilized peptide remains stable for 24 months or longer.
Once reconstituted with bacteriostatic water for injection, Melanotan 2 solutions should be stored refrigerated at 2-8°C and used within 28 days. Avoid repeated freeze-thaw cycles, which can degrade peptide structure and reduce activity.
Visual inspection should be performed before each use. The reconstituted solution should be clear and colorless. Reject any solution that appears cloudy, discolored, or contains visible particulate matter.
For step-by-step reconstitution calculations, see our reconstitution calculator.
For laboratory research use only. The compound described on this page is intended exclusively for in vitro research and laboratory experimentation by qualified researchers and is not for human or veterinary use. It is not a drug, food, dietary supplement, or cosmetic, and has not been approved by the FDA, Health Canada, EMA, or any other regulatory authority for the diagnosis, treatment, cure, mitigation, or prevention of any disease or medical condition. The information provided on this page is for educational and reference purposes only and does not constitute medical advice. By accessing this content you confirm that you are a qualified researcher purchasing for legitimate laboratory purposes.