Claimed effect · Melanotan II

Does Melanotan II help with erectile function?

C
Grade C — weak human evidenceSmall crossover RCTs · effect size: moderate
Short answerWeak human evidence. Small crossover RCTs: enough to be interesting, not enough to count on. Where an effect is seen it is a moderate effect. In a 10-man double-blind crossover, Melanotan II produced clinically apparent erections in most treated men, far exceeding placebo — small, early, never taken to phase 3.

What the studies show

In a 10-man double-blind crossover, Melanotan II produced clinically apparent erections in most treated men, far exceeding placebo — small, early, never taken to phase 3.

“Mean duration of tip rigidity greater than 80% was 38.0 minutes with Melanotan-II and 3.0 with placebo (p=0.0045).”

Verbatim, from the abstractWessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study. J Urol, 1998;160:389–393

A few small or poorly-controlled human studies. Enough to be interesting; not enough to count on. Most of what gets called “clinically proven” online lives here.

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In context

Melanotan II is a synthetic cyclic peptide that mimics α-melanocyte-stimulating hormone. Small early trials in the 1990s showed it darkens skin and, separately, triggers erections in men — the two effects it is still sold for. It has never completed later-stage trials and is not approved anywhere. Reported harms include nausea, uncontrolled erections, darkening and change of moles, and case reports of serious events such as kidney infarction, which is why regulators warn against it.

Melanotan II is not approved. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is Melanotan II proven to help with erectile function?
No. The human evidence is weak (Small crossover RCTs); LYO grades it C.
What studies are behind the grade?
In a 10-man double-blind crossover, Melanotan II produced clinically apparent erections in most treated men, far exceeding placebo — small, early, never taken to phase 3.
Is Melanotan II approved for this?
No. Melanotan II is not approved; it is not an approved medicine for any indication in the jurisdictions LYO covers.

Other outcomes for Melanotan II

Written and maintained by LYO Research — how pages are written and checked. Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →