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No. 045 · Hormones & Drive · Tanning Peptide

Melanotan II

MT-IIMelanotan 2

A Tier A · Controlled human trials how tiers work →
  • Not FDA approved
  • WADA ✗ S0
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7 residues C50H69N15O9
O O O O O O O O O N H N H N H N H N H N H N H N H N H N 2 H N H N N N 2 H N 2 H

2D structure from PubChem CID 92432 (melanotan-II), matched by molecular formula. Hydrogens on carbon are implied.

Melanotan II sequence fingerprint
  • Nonpolar 1
  • Positive charge 3
  • Negative charge 1
  • Modified / non-standard 2

Each dot is a residue placed around the ring from N- to C-terminus; its distance from the centre reflects its chemistry.

01

Quick answers

What is Melanotan II?
A synthetic melanocortin peptide that stimulates melanogenesis, producing a tan without UV exposure. Not the same as afamelanotide (Scenesse), a different, linear α-MSH analogue that the FDA and EMA have approved for erythropoietic protoporphyria.
How strong is the evidence for Melanotan II?
Tier A (controlled human trials) on the peptidemeta evidence scale. Small double-blind, placebo-controlled crossover trials in men with erectile dysfunction (1998, 2000) and phase 1 tanning studies. Never approved anywhere.
Is Melanotan II FDA-approved?
No. Melanotan II is not approved by the FDA for any use.
Is Melanotan II banned in sport?
Yes. Melanotan II is prohibited in sport by the World Anti-Doping Agency under S0 (non-approved substances).
How does Melanotan II work?
Melanotan II is a cyclic heptapeptide analog of alpha-MSH that non-selectively activates melanocortin receptors MC1R through MC5R. MC1R activation on melanocytes stimulates cAMP signaling and tyrosinase expression, increasing eumelanin synthesis and skin pigmentation.
What is known about the safety of Melanotan II?
Small human trials reported nausea, stretching/yawning, fatigue/somnolence, and spontaneous erections. Concerns from case reports include darkening of moles that may complicate melanoma detection and priapism in males.

Last reviewed · editorial policy · markdown

02

Evidence

  1. D In vitro
  2. C Animal
  3. B Human pilot
  4. A RCT
  5. S Approved

TIER A — At least one published randomized controlled trial in humans.

Small double-blind, placebo-controlled crossover trials in men with erectile dysfunction (1998, 2000) and phase 1 tanning studies. Never approved anywhere.

Tiers rate the strength of published evidence — not effectiveness, safety, or a recommendation.

03

At a glance

Residues
7 amino acids, N→C
Molecular weight
1,024.2 Da
Formula
C50H69N15O9
Routes studied
Subcutaneous, Intramuscular Routes used in published research
FDA
Not approved
WADA
Prohibited · S0 Non-approved substances
04

Sequence

N → C · 7 residues · hover, tap, or use arrow keys to inspect

Note Cyclic heptapeptide: side-chain lactam bridge between Asp2 and Lys7; C-terminal amide.

05

Overview

A synthetic melanocortin peptide that stimulates melanogenesis, producing a tan without UV exposure. It also has notable sexual arousal and appetite-suppressive side effects.

Research status Small human studies only (a 1996 pilot phase I study and small placebo-controlled crossover trials in erectile dysfunction, 1998–2000); never approved anywhere; widely studied melanocortin pharmacology

06

Mechanism

Melanotan II is a cyclic heptapeptide analog of alpha-MSH that non-selectively activates melanocortin receptors MC1R through MC5R. MC1R activation on melanocytes stimulates cAMP signaling and tyrosinase expression, increasing eumelanin synthesis and skin pigmentation. MC4R activation produces the sexual arousal and appetite-suppressant side effects.

07

Effects reported in research

Reported outcomes, not promises. Some come from controlled human trials; others may be from smaller or preclinical studies — check the studies below.

  • Increased melanin production and skin tanning
  • Enhanced libido as a side effect
  • Mild appetite suppression
  • Darkened moles and nevi (monitor closely)
08

Safety & unknowns

Small human trials reported nausea, stretching/yawning, fatigue/somnolence, and spontaneous erections. Concerns from case reports include darkening of moles that may complicate melanoma detection and priapism in males. Not FDA-approved. Multiple regulatory agencies have issued warnings about unlicensed products.

Unknowns. Trial safety data apply to the populations, formulations and conditions studied.

Informational only — not medical advice. peptidemeta publishes no dosing, protocols, or sourcing. Talk to a qualified clinician about any treatment decision.

09

Studies [2]

  1. Clinical trial 2000

    Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction

    Wessells H, Gralnek D, Dorr R, et al. Urology

    Double-blind, placebo-controlled crossover trial in 10 men in which Melanotan II initiated erections more often than placebo, with nausea and yawning as common side effects.

    [pubmed] [doi]

  2. Clinical trial 1996

    Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study

    Dorr RT, Lines R, Levine N, et al. Life Sciences

    Single-blind, placebo-controlled pilot phase I study in 3 healthy men; MT-II increased skin pigmentation in 2 subjects and caused mild nausea, somnolence, and spontaneous erections.

    [pubmed] [doi]

11

Status sources

Sources behind the tier, regulatory status, sequence and dates on this page.

12

Cite this entry

$ cite --format=apa

peptidemeta. (2026). Melanotan II. In peptidemeta: The peptide library, ranked by evidence. Retrieved November 8, 2026, from https://peptidemeta.com/p/melanotan-ii/

$ cite --format=bibtex 
@misc{peptidemeta-melanotan-ii,
  title = {Melanotan II},
  author = {{peptidemeta}},
  year = {2026},
  howpublished = {\url{https://peptidemeta.com/p/melanotan-ii/}},
  note = {Accessed 2026-11-08}
}

Accessed date reflects when you opened this page. Cite primary studies for scientific claims.

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