How common is safety in humans with Melanotan II?

What the studies show

Nausea, flushing, spontaneous erections and darkening of moles are common; case reports describe rhabdomyolysis and kidney infarction, and dermatologists warn that new or changing moles can mask melanoma. No systematic long-term safety data exist.

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.

1. 1
   Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study.J Urol, 1998;160:389–39310 men, crossover; the erection data.
2. 2
   Case reports of serious harm with melanotan II (e.g. renal infarction).CEN Case Rep and others, 2020Illustrative of the unmonitored-use risk.

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

Other outcomes for Melanotan II

• CErectile function (psychogenic ED)Small crossover RCTs
• CSkin tanningPilot studies (n≈3–12)

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 →