Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II.
Level 2 - randomized trial
Double-blind placebo-controlled crossover trial
PubMed 11035391 · doi:10.1038/sj.ijir.3900582
What was done
Twenty men with psychogenic and organic erectile dysfunction participated in a double-blind, placebo-controlled crossover trial administering Melanotan II. Penile rigidity was recorded over 6 hours using RigiScan without sexual stimulation, and questionnaires assessed sexual desire and adverse effects.
What was found
Melanotan II produced penile erection in 17 of 20 men in the absence of sexual stimulation, with a mean duration of 41 minutes of tip rigidity greater than 80%. Increased sexual desire occurred after 13/19 (68%) doses of Melanotan II versus 4/21 (19%) doses of placebo (P < 0.01). Yawning and nausea were frequent side effects, with severe nausea reported by 12.9% of subjects at a dose of 0.025 mg/kg.
Why it matters
This study provides early clinical evidence that non-selective melanocortin receptor agonism can independently stimulate penile erections and enhance sexual motivation in men with erectile dysfunction.
Limits
The sample size is very small (20 subjects) and mixes organic and psychogenic etiologies without reporting subgroup differences. Assessments were conducted in an artificial laboratory setting measuring mechanical rigidity rather than successful sexual intercourse, and side effects like nausea were common.
Cited by
- supports Melanotan II stimulates strong penile erections.