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Melanotan I (Afamelanotide): The Approved Drug Whose Label Treats Tanning as a Side Effect

Melanotan I is afamelanotide, and it is one of the few compounds in this library with a real approved product — a 16 mg implant for a rare genetic photosensitivity disease. Its US label lists the darkening of moles as a risk to be monitored twice a year.

PeptideFDA-approved as SCENESSEApproved indication is a rare photosensitivity disease, not tanning

Caroline S · Published 2026-09-15

Length

13 amino acids

Sequence

Ac-Ser-Tyr-Ser-Nle-Glu-His-(D)Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂ — a synthetic tridecapeptide, molecular weight 1,646.85 as the anhydrous free base

Origin

A structural analogue of alpha-melanocyte-stimulating hormone (α-MSH), the body's own 13-amino-acid pigment signal, modified at two positions (norleucine at 4, D-phenylalanine at 7) to resist breakdown. Developed at the University of Arizona and brought to market by Clinuvel Pharmaceuticals.

Last reviewed

2026-09-15

What is it good for?

It is approved for one thing: increasing pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria (EPP). It is sold on the grey market for something else entirely — tanning without sun.

Illustration: A pale, translucent cylindrical implant on a white surface with a deep green background.
Illustration

What it is

Melanotan I is afamelanotide: a synthetic peptide of 13 amino acids, built as a structural analogue of α-melanocyte-stimulating hormone, the body's own pigment signal. Two substitutions — norleucine at position 4 and D-phenylalanine at position 7 — make it far more resistant to breakdown than the natural hormone.

The full sequence is printed on its approved label: Ac-Ser-Tyr-Ser-Nle-Glu-His-(D)Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂, molecular weight 1,646.85.

It acts at the melanocortin 1 receptor on pigment cells and raises eumelanin production — and, as the label states, it does so independently of exposure to sunlight or artificial UV light. That single sentence explains both the medicine and the grey market.

It is not to be confused with the cyclic tanning analogue sold as MT-II, a smaller cyclic peptide that binds several melanocortin receptors, has no approved product anywhere, and carries most of this compound family's case-report literature.

The part that makes this entry unusual: it is an approved drug

Most compounds in this library have no approved product. This one does.
Product SCENESSE (afamelanotide) implant, Clinuvel Inc.
First US approval 2019
Form A single bioresorbable rod, ~1.7 cm long, 1.45 mm across, 16 mg of afamelanotide in a PLGA copolymer
Route Subcutaneous, above the anterior supra-iliac crest, by a trained physician using an implantation cannula
Interval Every 2 months
Indication To increase pain-free light exposure in adult patients with a history of phototoxic reactions from erythropoietic protoporphyria

Erythropoietic protoporphyria is a rare inherited disorder in which a light-sensitive compound accumulates and sunlight causes severe burning pain, frequently with nothing visible on the skin. The approved endpoint is time in light without pain. Appearance is not the point of the drug; tolerating daylight is.

The label's own warning is the finding

Read the warnings section and the drug's second effect is stated flatly:

May induce darkening of pre-existing nevi and ephelides due to its pharmacological effect.

So the label recommends a full-body skin examination twice yearly to monitor existing and new pigmented lesions, for the duration of treatment.

That is the whole story of this compound in two lines. The pigment change that the grey market sells as the product is, on the approved label, a monitored risk attached to a supervised medicine — because a drug that darkens moles interferes with the main visual signal clinicians use to catch melanoma early.

The other labelled risk is allergic: serious hypersensitivity reactions, including anaphylaxis, have been reported in postmarket use.

What the registry contains

More than twenty ClinicalTrials.gov records, and almost all of them belong to the same sponsor:

Programme Records and enrolment
EPP (the approved use) Phase 3 at 74, 93 and 100 participants, plus a 16-patient safety extension
Polymorphic light eruption Phase 3 at 31 and 18
Vitiligo, with narrow-band UVB Phase 1–2 at 56, 21 and 15; one phase 3 of 200 active, not recruiting
Proof-of-concept elsewhere Single-digit studies, including three participants in acne

125 subjects received the drug across the EPP studies. That is the size of the clinical safety base behind an approved product — small, as it is for most rare-disease drugs, and vastly larger than anything behind the injectable version.

Its pharmacokinetics were measured in 12 healthy adults: high variability, a mean maximum plasma concentration of 3.7 ± 1.3 ng/mL, and for 9 of the 12 the last measurable concentration at 96 hours after one implant.

What the published literature says about moles

350 PubMed records name melanotan or afamelanotide as of 2026-09-15; 104 name afamelanotide specifically, 68 concern protoporphyria, and 7 carry the randomized-trial publication type.

30 records join the compound to melanoma or to nevi, and classifying them matters more than counting them:

  • Most concern Melanotan II, not this molecule — eruptive naevi, dermoscopic change, melanoma-in-situ and melanoma case reports from several countries, and a 2025 question about oral mucosal melanoma after nasal-spray use.
  • The clearest Melanotan I report is a 2014 case of eruptive naevi and darkening of pre-existing naevi 24 hours after a single mono-dose injection. One injection.
  • Pigment change is documented in supervised use too: a 2021 paper reports clinical and dermoscopic changes in acquired melanocytic nevi in patients treated with afamelanotide.

A case report cannot establish that this compound causes melanoma; that is not what case reports do. What this set does establish is that mole change is a real, repeatedly documented, sometimes rapid consequence of activating this receptor — which is exactly what the approved label says, and exactly why it asks for surveillance.

Where it stands

Afamelanotide is a medicine with a narrow, well-defined use, delivered in a form a person cannot replicate: a solid implant releasing a known quantity, placed by a clinician, with twice-yearly skin checks written into the label.

"Melanotan 1" sold as a vial is the same molecule with none of that around it — no established dose, no established interval, no purity guarantee, and no skin surveillance. The compound works; the pigment effect is real and the mechanism is not in doubt. What differs between the two products is everything that makes the effect safe to have.

Related entries: the case-report literature on the unlicensed cyclic analogue, and what a peptide is for why a 13-amino-acid chain behaves like a hormone rather than a nutrient.

Sources

  • SCENESSE (afamelanotide) implant, prescribing information, Clinuvel Inc. Read on DailyMed 2026-09-15 — indication, description and sequence, mechanism, pharmacokinetics, warnings, skin monitoring, geriatric use.
  • ClinicalTrials.gov, queried 2026-09-15 for afamelanotide: NCT00979745, NCT01605136, NCT04053270, NCT04578496 (EPP); NCT04704713, NCT00472901 (polymorphic light eruption); NCT01430195, NCT04525157, NCT01382589, NCT06109649 (vitiligo with NB-UVB); NCT03634137 (implant pharmacokinetics); NCT04943159 (acne).
  • Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. 2017, PubMed record in the melanotan set.
  • Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan I. 2014.
  • Clinical and dermoscopic changes of acquired melanocytic nevi of patients treated with afamelanotide. 2021.
  • PubMed counts, run 2026-09-15 via the NCBI E-utilities esearch endpoint: afamelanotide[tiab] OR "melanotan"[tiab] OR "melanotan-1"[tiab] OR "melanotan I"[tiab] — 350; afamelanotide[tiab] — 104; the melanotan/afamelanotide set with "randomized controlled trial"[pt] — 7; with protoporphyria or EPP — 68; with melanoma, nevi, naevi or nevus — 30.

What the research shows

Increases eumelanin in skin

Established, and the mechanism is on the approved label: it acts at the melanocortin 1 receptor and raises eumelanin production independently of any sun or UV exposure

Reduces phototoxic pain in erythropoietic protoporphyria

The approved indication, supported by company-run phase 3 trials of 74, 93 and 100 participants and a 16-patient safety extension

Repigments vitiligo

Under investigation with narrow-band UVB phototherapy — phase 1 and 2 studies of 56, 21 and 15 participants, and one phase 3 of 200 still active, not recruiting. No result is published

Is safe as a tanning product

Not studied. No trial has ever tested it for cosmetic tanning, and the label requires twice-yearly full-body skin examination during approved use

Darkens existing moles and freckles

Stated on the approved US label as a pharmacological effect to be monitored — the same effect the grey market treats as the point

Bars show how much of the evidence is in humans, not how well anything works.

Where it stands

United States

APPROVED. SCENESSE (afamelanotide) implant, Clinuvel Inc., initial US approval 2019 — a 16 mg bioresorbable rod placed subcutaneously above the anterior supra-iliac crest every 2 months, by a trained physician. Label read on DailyMed 2026-09-15.

Approved indication

To increase pain-free light exposure in adult patients with a history of phototoxic reactions from erythropoietic protoporphyria. Nothing about tanning, cosmetics or appearance appears in the indication.

Label warnings

Serious hypersensitivity reactions including anaphylaxis have been reported in postmarket use. The label states the implant may induce darkening of pre-existing nevi and ephelides due to its pharmacological effect, and recommends a twice-yearly full-body skin examination to monitor existing and new pigmented lesions.

Published record

350 PubMed records name afamelanotide or melanotan in title or abstract as of 2026-09-15; 104 name afamelanotide specifically, 7 carry the randomized-controlled-trial publication type, and 68 concern protoporphyria.

Trial registry

More than 20 ClinicalTrials.gov records, and essentially all of them are Clinuvel's: phase 3 in EPP (74, 93 and 100 participants, plus a 16-patient safety extension), phase 3 in polymorphic light eruption (31 and 18), phase 1–2 in vitiligo with narrow-band UVB (56, 21, 15), and single-digit proof-of-concept studies in acne and other conditions. One phase 3 of 200 in vitiligo is active and not recruiting.

How it is sold

As 'Melanotan 1' or 'MT-1' — a lyophilised vial for self-injection, marketed for tanning, at a dose, interval and purity nobody has established. The approved product is not a vial and is not self-administered.

Frequently asked questions

Is Melanotan I the same as Melanotan II?

No. Melanotan I is afamelanotide, a 13-amino-acid linear analogue of α-MSH that binds predominantly to the melanocortin 1 receptor, and it has an approved product. Melanotan II is a smaller cyclic peptide that hits several melanocortin receptors, which is why it also affects sexual arousal, and it has no approved product anywhere. They are different molecules with different receptor profiles and completely different regulatory standing.

Is Melanotan I legal or approved?

The medicine is. SCENESSE, a 16 mg afamelanotide implant, has been approved in the United States since 2019 for adults with erythropoietic protoporphyria, and is placed under the skin by a physician every two months. That approval covers a specific implant for a specific rare disease. It does not make a vial of 'MT-1' bought online a legal medicine, and nothing about tanning appears in the approved indication.

What is erythropoietic protoporphyria?

A rare inherited disorder of haem synthesis in which a light-sensitive compound accumulates and sunlight causes severe burning pain, often within minutes and often with no visible rash. Patients organise their lives around avoiding light. The approved endpoint reflects that reality: the product is approved to increase pain-free light exposure, not to treat a skin appearance.

Does it work for tanning?

It increases eumelanin, and the approved label says so plainly — production rises independently of any sun or UV exposure. That is why the grey market exists. What has never been studied is tanning as a purpose: no trial has tested the compound for cosmetic pigmentation, in anyone, at any dose, and the approved use is supervised precisely because the pigment effect is not confined to the skin someone wants darker.

What are the documented risks?

Two distinct sets. On the approved product, the label reports serious hypersensitivity reactions including anaphylaxis in postmarket use, and states that pre-existing moles and freckles may darken as a pharmacological effect — which is why a twice-yearly full-body skin examination is recommended. On the unlicensed injectables, the published record is a body of case reports: eruptive new moles, darkening and dermoscopic change in existing ones, and several reports of melanoma, mostly involving Melanotan II. A 2017 review in this literature is titled for the risks of unregulated use of α-MSH analogues.

Why does the label ask for skin checks?

Because the drug's mechanism does not distinguish between skin you want darker and a mole that was already there. Melanocortin 1 receptor activation raises pigment production across pigment cells, and the label names darkening of pre-existing nevi and ephelides as a pharmacological effect. A changing mole is also the classic warning sign clinicians look for in melanoma, so a drug that changes moles makes surveillance harder, not easier. That is the reason for the twice-yearly examination, and it is the single most useful sentence on the label for anyone considering the grey-market version without one.

What else is it being tested for?

Vitiligo is the main one, in combination with narrow-band UVB phototherapy: phase 1 and 2 studies of 56, 21 and 15 participants, and one phase 3 of 200 that is active and not recruiting. There are also completed phase 3 studies in polymorphic light eruption (31 and 18 participants) and a scatter of very small proof-of-concept studies, including one in acne with three participants. Almost every record in the registry carries Clinuvel as its sponsor.

How does the approved dose compare with what people inject?

They are not comparable, and the difference is the point. The approved product is a single solid rod delivering 16 mg from a bioresorbable polymer over weeks, placed by a physician every two months, with the pharmacokinetic study showing measurable plasma levels out to 96 hours. The grey-market product is a powder reconstituted at home and injected on a schedule that has no clinical source. This library reports what the label states and what the registry holds; neither contains an instruction for anyone.