Sexual Health · Skin
Melanotan II
Also known as: MT-II, MT2, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
A synthetic non-selective melanocortin receptor agonist used off-label for skin tanning and sexual function, with multiple documented safety concerns and no regulatory approval.
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Strength of human clinical evidence — A (strongest) to D (mostly preclinical). This reflects research maturity, not safety or suitability.
Vial Theory provides educational research summaries only. Content is not medical advice, diagnosis, treatment, dosing guidance, or individualized suitability screening. Regulatory status can change over time and varies by jurisdiction.
Key Takeaways
- ›Melanotan II is an unapproved melanocortin-activating peptide used off-label for tanning and sexual function.
- ›It is distinct from the FDA-approved related drugs bremelanotide (Vyleesi) and afamelanotide (Scenesse).
- ›Medical case reports document changing moles/pigmented lesions and rarer serious events; regulators have issued warnings.
- ›Gray-market product is unverified for purity and sterility, and self-injection adds risk.
- ›It is not approved and has real safety concerns. Speak with a licensed healthcare professional.
What It Is
Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH) that acts as a non-selective agonist at multiple melanocortin receptors (MC1R, MC3R, MC4R, MC5R). It was developed in the late 1980s and early 1990s at the University of Arizona by researchers including Mac Hadley and Victor Hruby during a broader melanocortin research program that also produced bremelanotide (PT-141, now approved as Vyleesi).
The two compounds were developed from related starting points but diverged in their pharmacological and clinical profiles: bremelanotide has more selectivity toward MC4R and was developed for sexual dysfunction indications, while melanotan II retains broader melanocortin receptor activity including MC1R agonism, which drives skin pigmentation effects. The original academic development of melanotan II was as a candidate skin-cancer prevention agent (the rationale being that increased eumelanin production could provide photoprotection), but the compound was never developed by an established pharmaceutical sponsor into a registered product.
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Disclaimer: This content is for educational and research purposes only and is not medical advice. Always consult a licensed healthcare professional before making health-related decisions.