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Melanocortin

Melanotan II

A synthetic melanocortin peptide sold for tanning — unapproved everywhere, and routinely confused with genuinely approved melanocortin medicines.

L2PreclinicalExperimental / researchUnclearVery low confidenceLast reviewed 2026-08-23
SC injection· unapprovedNasal· unapproved

Also known as: MT-II, MT2, melanotan

Evidence passport

Last reviewed 2026-08-23

Evidence level
L2Preclinical
Confidence
Very low confidence
Human efficacy
15/100
Human safety
10/100
Regulatory status
Experimental / research
Development
Unclear
Routes
SC injection· unapprovedNasal· unapproved
Evidence base
Mostly preclinical
Furthest stage
Not established
Source curation
Sources fully curated
Clinical maturity
Limited early human study; no approved development programme

Most of this evidence comes from animals and cells

The supporting research for Melanotan II is predominantly preclinical (Level 1–2). That is a legitimate starting point for science and a poor basis for personal decisions. Human results are not simply a scaled-up version of mouse results.

Overview

Human evidence15/100
Preclinical evidence55/100
Human safety evidence10/100

Clinical maturity: Limited early human study; no approved development programme

Routes & formulations

Marketed / research routes — never approved

SC injection· unapprovedNasal· unapproved

Marketed in the research market as injections and nasal sprays. No approved formulation exists for any route, and tanning-market availability is not evidence of efficacy or safety.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

  5. Phase III

  6. Approved

UnclearFurthest stage not established in our curated record

No active approved development programme in the curated record; early research history only.

What it is

A synthetic cyclic analogue of alpha-MSH developed in early skin-cancer-prevention research, later leaking into the unregulated tanning market.

What people claim

  • Tans the skin without sun exposure
  • Suppresses appetite
  • Increases libido

What the evidence actually says

Skin darkening is a real pharmacological effect of MC1R activation — that was never in doubt. What does not exist is a demonstration that Melanotan II is a safe or approvable medicine, and regulators have consistently said the opposite. A visible effect is not evidence of safety, and it is not the same thing as approval of the distinct melanocortin medicines that did complete development.

Human evidence

  • Small early-phase human studies of pigmentation and sexual effects; no adequate controlled safety or efficacy programme.

Preclinical evidence

  • Melanocortin receptor pharmacology and animal pigmentation studies.

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Non-selective melanocortin receptor agonism: MC1R drives skin pigmentation; MC4R activity relates to appetite and sexual effects.

Safety and unknowns

  • Spontaneous sexual effects and nausea are documented pharmacological effects, reported in early studies and adverse-event literature.
  • There is no systematic long-term human safety dataset; the 503A Category 2 listing reflects identified significant safety risks for compounding.
  • Unapproved supply quality is a separate and serious risk.

Cancer relevance

Theoretical / mechanistic concern only

A recurring concern is that stimulating melanocytes could interact with melanoma risk. No human data demonstrate that Melanotan II causes cancer — and none establish it is safe in that respect. Unstudied is not reassuring.

Regulatory status

Not an approved medicine in any major region and flagged on the FDA 503A Category 2 list as a bulk substance presenting significant safety risks for compounding. It must not be confused with the approved melanocortin medicines bremelanotide, afamelanotide and setmelanotide, each of which has its own narrow, specific indication.

Evidence grade

L2PreclinicalVery low confidence

Animal, organoid or tissue studies. Mice are not tiny humans.

What would change our rating?

  • A completed, regulator-quality clinical programme — which, notably, no sponsor has pursued to approval.

References and sources

Sources fully curated

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

No recorded changes yet. Baseline position set on 2026-08-23.

Related claims we’ve checked

MisleadingL2PreclinicalMelanocortin

“Melanotan II is basically the same approved medicine as afamelanotide.”

Misleading — related chemistry, completely different regulatory reality.

  • Afamelanotide (Scenesse) completed a full development programme and is approved for one rare disease, erythropoietic protoporphyria, as a clinician-administered implant.
  • Melanotan II has no approval anywhere and sits on the FDA's 503A Category 2 list of substances with identified significant safety risks for compounding.
  • Saying 'it's basically the approved one' erases the entire difference between a finished trial programme and an abandoned one.
Last reviewed 2026-08-23Compound profile