MT-1What the studies show

Q: What kind of evidence exists for melanotan I (afamelanotide)?

Large human trials. Two placebo-controlled phase 3 trials in a rare light-sensitivity disease, behind an FDA approval; small early tanning studies and one vitiligo trial; nothing at all on the unregulated "melanotan I" sold online.

A tanning peptide from 1980s Arizona that became Scenesse, an approved implant for a rare disease in which sunlight causes burning pain.

5 min read · Large human trials · Updated November 2026

In short

Name: melanotan I (afamelanotide) (sold by Progression Labs as MT-1)
Evidence: Large human trials
Bottom line: Two placebo-controlled phase 3 trials in a rare light-sensitivity disease, behind an FDA approval; small early tanning studies and one vitiligo trial; nothing at all on the unregulated "melanotan I" sold online.

Before you read this

This guide explains what published studies found. That is all it is.

It is not medical advice and it is not instructions for using anything. Where a dose appears, we are reporting what a named study gave the people or animals in it — a fact about the study, not an instruction to you.

The compounds here are not approved by the FDA for use in people and are sold for laboratory research only. A study tells you what happened to the subjects in it; it does not tell you what would happen to you. Talk to a doctor first.

What it is

Melanotan I is a 13-amino-acid analogue of alpha-melanocyte-stimulating hormone, the hormone that tells pigment cells to make melanin. Chemists at the University of Arizona built it in the 1980s by changing two amino acids in the natural hormone so that it would last longer in the body; its chemical name is [Nle4, D-Phe7]-alpha-MSH, and its drug name is afamelanotide ¹. It is one of the few peptides on this site that is an approved medicine. As Scenesse, an implant placed under the skin, afamelanotide was approved by the U.S. FDA in 2019 to increase pain-free time in sunlight for adults with erythropoietic protoporphyria, a rare inherited disease in which light causes burning pain within minutes ². Everything else that circulates about it — tanning, vitiligo — comes from trials that did not lead to an approval.

The studies below call this molecule melanotan I (afamelanotide). Progression Labs sells it as MT-1; the guide uses the store's name and the papers use theirs.

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Tanning before it was a medicine

The first human study was in 1991: three men were given melanotan I under the skin daily for ten days and their skin darkened without sun, most on the face and neck, where pigment cells are already active, and least on skin that never sees the sun ¹. In 2004 the same group paired it with ultraviolet light. Healthy volunteers received the peptide or placebo along with small doses of UV, and the peptide group tanned more and had fewer sunburn cells in skin biopsies — the damaged cells UV leaves behind ³. The idea was a tan that protects, and the development path went to the people who need protection most.

The porphyria trials

Erythropoietic protoporphyria makes skin react to sunlight with burning pain, and people with it organise their lives around shade. The 2015 trials in the New England Journal of Medicine were two phase 3 studies, 74 patients in Europe and 94 in the United States, in which an afamelanotide implant or a placebo implant was placed under the skin every two months ⁴.

In the U.S. trial, patients on afamelanotide spent a median of 69.4 hours in direct sunlight on pain-free days over six months, against 40.8 hours on placebo; in the European trial, which counted only direct sun between 10 a.m. and 3 p.m. over nine months, it was 6.0 hours against 0.75. Quality-of-life scores improved with the drug, and the common side effects were nausea, headache and reactions at the implant site ⁴. Those are the numbers the approval rests on: more time outside without pain, in a disease where the baseline is almost none.

Vitiligo

Because the peptide pushes pigment cells to work, it was tried in vitiligo, where patches of skin have lost them. A 2015 randomised trial in 55 people compared narrowband UV-B light alone with light plus afamelanotide; the combination repigmented a larger share of the affected skin and did it sooner, with the largest difference in darker skin types ⁵. Afamelanotide is not approved for vitiligo.

Side effects, and what is sold under the name

The label lists implant-site reactions, nausea, sore throat, cough, fatigue, dizziness, darkening of the skin and new moles as the common side effects, and it asks for a full skin examination twice a year, because a drug that stimulates pigment cells could in principle change moles; the approval trials ran about a year, and longer experience comes from registries rather than controlled studies ⁶. The drug is given only as an implant placed by a trained clinician ⁶.

The vials labelled "melanotan I" sold online as tanning products are not the approved drug. They are not made under its controls, their content is unverified, and no trial has tested them.

What these studies are, and aren't

Large human trials. Two placebo-controlled phase 3 trials in a rare light-sensitivity disease, behind an FDA approval; small early tanning studies and one vitiligo trial; nothing at all on the unregulated "melanotan I" sold online.