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Melanotan II

Also known as: MT-II, MT-2, Melanotan-2

Research Only

Molecular Formula

C50 H69 N15 O9

Molecular Weight

1,024.18 Da

Half-Life

Unknown in human systemic circulation (lacks primary human PK studies; acute erectile effects last ~4–8 hours; skin pigmentation changes persist 2–4 weeks)

Sequence

Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂

Clinical Applications & Evidence

Mechanism of Action

Non-selective agonist of melanocortin receptors. Peripheral MC1R activation stimulates eumelanin synthesis in melanocytes. Central MC3R/MC4R activation in the hypothalamus and spinal cord mediates acute neurogenic erectile response and appetite suppression. Unapproved nasal spray products lack validated clinical pharmacokinetic, bioavailability, or safety profiles.

Investigated Uses

  • Psychogenic erectile dysfunction (Investigational — early pilot proof-of-concept studies in 3–10 men; unproven for organic ED)
  • Nonsegmental vitiligo (Investigational — 2026 Phase 2 trial NCT07437560 actively recruiting; no results published)
  • Experimental melanogenesis / skin pigmentation (Demonstrated in early pilot trials; unapproved for cosmetic use)
Early Clinical / Animal Models

Regulatory & Safety Status

FDA Status

Research Only

WADA / Athletic Status

Prohibited at All Times (WADA S4.4.1)

Known Side Effects

Acute nausea, facial flushing, yawning, and stretching complex (common in early pilot trials)Spontaneous penile erections (acute pharmacological effect lasting 4–8 hours)Darkening of existing nevi (moles) and hyperpigmentationRare case reports of priapism, rhabdomyolysis, renal infarction, and hypertension from unapproved commercial productsTGA Safety Warning: Induced skin pigmentation does NOT protect against UV radiation or sun damage

Contraindications

  • WADA-tested athletes (Prohibited at all times under S0 Non-Approved Substances)
  • Personal or familial history of melanoma, dysplastic nevi, or atypical skin lesions (Risk-based precaution)
  • Uncontrolled hypertension or severe cardiovascular disease (Risk-based precaution)
  • Pregnancy, lactation, and history of priapism or eating disorders (Unstudied safety profile)

Drug Interactions

  • PDE5 inhibitors (Theoretical additive risk of prolonged erection or priapism; unstudied clinically)
  • Antihypertensives and sympathomimetics (Theoretical cardiovascular hemodynamic overlap; unstudied)

Citations & Clinical Trials

PubMed Evaluation of Melanotan-II in a Pilot Phase-I Clinical Study (1996) PubMed Pilot Study of Melanotan II in Men with Psychogenic Erectile Dysfunction (1998) ClinicalTrials.gov Melanotan II as an Adjunct to NB-UVB for Nonsegmental Vitiligo (Recruiting 2026) FDA FDA Bulk Drug Substances Nominated for Compounding Presenting Safety Risks Therapeutic Goods Administration Australian TGA Safety Warning: Tanning Products Containing Melanotan World Anti-Doping Agency WADA 2026 Prohibited List — S0 Non-Approved Substances