Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II

We review our experience with Melanotan II, a non-selective melanocortin re ceptor agonist, in human subjects with erectile dysfunction (ED), Melanotan II was administered to 20 men with psychogenic and organic ED using a doub le-blind placebo-controlled crossover design, Penile rigidity was monitored for 6 h using RigiScan. Level of sexual desire and side effects were repor ted with a questionnaire. In the absence of sexual stimulation, Melanotan II led to penile erection i n 17 of 20 men, Subjects experienced a mean of 41 min Rigiscan tip rigidity > 80%. Increased sexual desire was reported after 13/19 (68%) doses of Mel anotan II vs 4/21 (19%) of placebo (P < 0.01). Nausea and yawning were freq uently reported side effects due to Melanotan II; at a dose of 0.025 mg/kg, 12.9% of subjects had severe nausea. We conclude that Melanotan II is a potent initiator of penile erection in m en with erectile dysfunction. Our findings warrant further investigation of melanocortin agonists and antagonists on penile erection.