Melanotan II
Limited human dataAlso known as: MT-II · Melanotan-2
A non-selective melanocortin-receptor agonist originally studied for skin tanning and erectile dysfunction, whose sexual-desire side effects led directly to the development of the FDA-approved drug bremelanotide (PT-141). Widely sold gray-market for tanning despite no approval for that use.
Mechanism (plain language)
Activates melanocortin receptors broadly (MC1R for pigmentation, MC3R/MC4R centrally for erection and desire pathways), unlike bremelanotide's narrower receptor profile.
What research suggests
Small double-blind, placebo-controlled crossover studies in men with both organic and psychogenic erectile dysfunction found Melanotan II reliably induced erections and increased self-reported sexual desire compared with placebo, using real-time monitoring (RigiScan).
Uncertainties & risks
Never approved as a drug; the tanning-injection gray market is unregulated with unknown purity. Nausea and yawning were frequent even in supervised trials, and case reports elsewhere describe pigmented lesions/moles with unsupervised use. Bremelanotide, not Melanotan II, is the version that went through modern regulatory trials.
Primary sources
Secondary citations for verification. Prefer the STACKD summary above for context before opening these.
- Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction
2000 · human
Double-blind crossover study found Melanotan II reliably induced erections and increased desire versus placebo.
- MT-II induces penile erection via brain and spinal mechanisms
2003 · animal
Mechanistic rat study localized the pro-erectile action to central and spinal melanocortin receptors.