Melanotan II

Educational overview

Melanotan II is listed in the ezGLP knowledgebase under Pigmentation. Evidence and regulatory status can vary by formulation, route, and jurisdiction.

Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone developed at the University of Arizona in the late 1980s as a more potent and longer-acting successor to Melanotan I. It is a non-selective melanocortin receptor agonist, activating MC1R on melanocytes to increase eumelanin production and also MC3R, MC4R, and MC5R, which accounts for its effects on sexual arousal, appetite, and nausea. Melanotan II is the parent structure from which bremelanotide, the approved drug in Vyleesi, was later derived. It is sold illicitly as a tanning agent, typically as a lyophilised powder for subcutaneous injection and increasingly as nasal sprays.

Formal clinical development stopped at early-phase studies in the 1990s and early 2000s, when small trials in healthy volunteers and men with erectile dysfunction documented tanning, penile erections, nausea, yawning, and stretching. No phase 3 programme was ever completed and there is no controlled safety database. The contemporary literature consists of case reports and case series describing melanoma arising or changing after Melanotan II use, rhabdomyolysis and renal dysfunction after overdose, posterior reversible encephalopathy syndrome, priapism, and rapid changes in existing moles. Regulator adverse-event schemes hold additional reports, but causality cannot be established from them, and product contamination or mislabelling cannot be excluded in any illicit-product report.

Melanotan II is not approved by any regulator for any indication in any country. In the United States the FDA has treated it as an unapproved new drug since at least 2007, when it issued a warning letter and later pursued debarment against a seller, and the FDA bulk drug substances review linked it to melanoma and posterior reversible encephalopathy syndrome. In Australia it is a prescription-only substance with no registered products, and the TGA has issued repeated alerts, infringement notices, and laboratory findings of inconsistent nasal-spray content. The MHRA describes Melanotan II products as unlicensed medicines whose safety, quality, and effectiveness have not been demonstrated. Supply for tanning is unlawful in these jurisdictions.

Because no licensed product exists, Melanotan II has no regulator-reviewed storage or handling guidance and every vial or spray relies on the seller's statements. Testing by the TGA found labelled and actual content diverging widely between bottles of the same product, so the stated concentration cannot be assumed. Peptide powders degrade with heat, light, and freeze-thaw cycling, and reconstituted solutions have no established beyond-use time; injection also introduces sterility and shared-equipment concerns that public-health agencies have documented among people injecting image-enhancing drugs. A dose log recording vendor, lot, stated content, reconstitution date, route, and storage, alongside an inventory record and a record of skin changes noted over time, is the only traceability available.

Category

Pigmentation

Routes represented

Subcutaneous (SubQ)

Storage context

Follow the dispensed product or pharmacy label; storage and beyond-use time vary by formulation.