Melanotan I Really Is the Approved Drug. What Circulates Is Not the Approved Product.

01What it is

Afamelanotide is a chain of 13 amino acids, a copy of the body's own alpha melanocyte stimulating hormone, the signal that tells pigment cells to make brown black pigment. Two positions differ from the natural hormone, and the paper that introduced it in 1980 reported that this analogue resists enzymatic degradation.

The identity question is usually where this site finds the vendors out. Not this time. PubChem holds one record, CID 16197727, carrying Afamelanotide, Melanotan I, Melanotan-1, CUV1647 and Scenesse in a single synonym list, formula C78H111N21O19, weight 1646.8, and the FDA label prints the same formula. One molecule, two names, one a street name and one a regulatory one. Melanotan II is a different molecule and does not read across: a seven residue peptide cyclised between residues 2 and 7, weight 1024.2. Hadley and Dorr wrote in a 2006 review that melanotan I was the one taken into clinical study for tanning of the skin and melanotan II the one taken into study for erectile dysfunction (PMID 16412534).

02What is approved, and what the approved thing is

Two approvals, both for the same narrow thing. In the European Union, SCENESSE, authorisation EU/1/14/969/001, first authorised 22 December 2014, and section 4.1 of its label is one sentence: prevention of phototoxicity, meaning damage triggered by light, in adult patients with erythropoietic protoporphyria. In the United States, NDA 210797, approved 8 October 2019, to increase pain free light exposure in adults with a history of phototoxic reactions from that disease. Neither mentions tanning, cosmetic use or healthy adults.

Then the dosage form, which is the whole entry. The approved product is an implant: a solid bioresorbable rod, meaning one the body dissolves and absorbs, holding 16 mg of drug in poly (DL-lactide-co-glycolide). The European label says it should only be prescribed by specialist physicians in recognised porphyria centres, and that administration should be performed by a physician trained and accredited by the marketing authorisation holder, which is a company rather than a person. Its insertion instructions run to sixteen bulleted items, ending with thirty minutes watching for a severe allergic reaction. One implant every two months, with three a year recommended in the European public summary and four its maximum, five the ceiling in the FDA review.

03What the trials measured, and how the numbers are filed

The endpoint was never tan depth. It was hours in sunlight without pain.

CUV039 is the sole pivotal study behind the European approval: 93 adults enrolled, of whom 48 received SCENESSE and 45 a dummy implant, three implants each over 180 days. Its protocol primary endpoint was total hours in direct sunlight between 10 am and 6 pm on days with no pain, and on the 46 and 43 patients analysed the medians were 69.4 hours against 40.8, clearing significance only on a one sided test, at 0.044, the kind that asks only whether the drug beat the dummy and not whether it did worse.

Now the number everyone quotes. The 24.0 extra pain free hours, and its range of uncertainty from 0.3 to 50.3, come from a Hodges-Lehmann estimate, a way of putting a single number on the typical gap between two groups, and the assessment report says that method was specified after the data were in, at the Rapporteurs' suggestion, then prints the figure under a heading for post hoc analyses. Chosen once the results were visible, in other words, which is a different grade of evidence from a plan written in advance, and the whole size of this drug's approved effect rests on it. Twenty four hours across six months is eight minutes a day, and the bottom of that range is eighteen minutes across the entire half year.

The other trial in the American label, CUV029, enrolled 74 adults, 38 on the implant and 36 on a dummy, medians of 6.0 hours against 0.75 across 270 days, a difference of about five and a quarter hours. Its primary endpoint was not prespecified either: the assessors record that its objectives were changed while the study was still running, and a 2013 inspection of it and its twin returned four critical findings among others. Both were dropped from the European case, leaving CUV039 alone.

SCENESSE was then authorised under exceptional circumstances, meaning the rarity of the disease made complete information impossible to obtain, and seven committee members appended a signed divergent position on 23 October 2014, saying the evidence from the single pivotal trial was not strong enough for an authorisation without specific obligations and that it remains unclear how far functional unblinding affected the estimated effects. Unblinding, because in a trial of a drug that turns your skin brown everybody can work out who got it.

04Whose evidence it is

Unusually for this site, the evidence belongs to the exact molecule. What it does not belong to is the exact product. Every efficacy trial above used the rod, in patients with a diagnosed disease, and so does the vitiligo study people cite (PMID 25230094).

The injected record in healthy people is real, old and small. Three male volunteers in 1997, ten doses over two weeks at 0.08 to 0.21 mg per kilogram under the skin, and seven volunteers in 2000, ten daily injections at a fixed 0.16 mg per kilogram, pigment measured in both against the subjects' own starting level rather than a control group (PMID 9113347, PMID 11045725). Three open label phase 1 trials in 2004, the first randomising 8 subjects, 4 to drug and 4 to saline, with the 3 of those 4 who tanned showing 47 percent fewer sunburn cells at the irradiated site (PMID 15262693). And in 2006 the largest injected study I found, in which 65 subjects completed a placebo controlled trial of injection into the abdomen at 0.16 mg per kilogram for three ten day cycles, pigment density up 41 percent against placebo in the fairest skinned volunteers and 12 percent against placebo in those who tan easily, a split by skin type rather than a treatment comparison (PMID 16763547). Its halving of sunburn cells applies only to the volunteers who burned at the lowest dose of light, and its abstract does not give the arm split, so 65 is the number who completed and not the number who received the peptide.

All of it dosed daily, roughly 5.6 to 14.7 mg an injection for a 70 kg adult by my arithmetic. And the vendor pages cite these trials openly: one dosing guide states that the peptide is approved as afamelanotide in Europe and the United States, summarises the rare disease result, then prints an injection chart under it.

05Where the injected schedule comes from

The trail does not go cold here. It leads to a real document used the wrong way.

One widely mirrored guide prints days 1 to 10 at 1 mg daily, then 2 mg a week for up to six months. Convention, reported as convention. The loading figure rests on stated caution rather than a study: the same page quotes the trial range correctly, 0.08 to 0.16 mg per kilogram a day, then says experts encourage erring on the side of safety and starting at about 1 mg daily. That is a fifth to a tenth of what was studied, and no study of 1 mg a day in humans turned up in my searches.

The maintenance figure does have a derivation, and the page shows its working: the trials used a 16 mg implant every 60 days, which it converts to 8 mg a month, and it then offers 2 mg a week, which it also writes as 8 mg a month. Those match on a four week month. Across a calendar year they do not quite, 104 mg against about 97 mg. The rate is close. The delivery matches nothing.

The citation attached to that figure is a 2020 three year observational study of 39 patients in Switzerland. I pulled the full text and searched all 36,759 characters, reference list included, for half-life, half life, twice, weekly and milligrams per anything. No matches. Every dosing sentence in that paper describes the implant, and it is being cited for three things it does not contain.

06Does the pharmacology allow it

The implant and the injection are not two ways of giving one drug. The peptide's own half life, the time for half a dose to clear, is short: about 30 minutes on the European label, 0.8 to 1.7 hours measured after injection under the skin in those three volunteers. A single injection is gone within a day.

The rod exists to stop that happening. Most of the drug is released in the first 48 hours, blood levels are below the limit of measurement by day 10, and the polymer is absorbed within 50 to 60 days. In 12 healthy adults FDA measured an apparent half life of about 15 hours, which out of a molecule with a 30 minute real one is the plastic doing the work rather than the peptide, and at five implants a year its review expected total exposure of 25 to 35 days a year, five to seven days after each dose. That is the envelope the approval sits inside. A weekly injection produces the opposite shape, and no published study of 1 mg or 2 mg by injection in people turned up in my searches, so there is no peak concentration to set against the implant's 3.7 nanograms per millilitre. Every published injection schedule I found dosed on weekdays: ten doses over two weeks in 1997 and 2000, ten days in 2004, three ten day cycles in 2006. None of them was weekly.

What the pharmacology does allow is why the protocol looks like it works. Pigment outlasts drug by weeks: in 1997 the tan peaked a week after drug administration and was still present three weeks after the ten dose regimen finished, and in guinea pigs in 2000 implants containing 4 mg kept skin darker for up to three months, in an abstract that does not give the number of animals (PMID 10888312). A radiator stays warm long after the boiler has cut out, and touching it tells you nothing about whether the boiler is running. The mirror cannot tell a user whether this week's injection did anything.

07What the regulators have on file

Go and look at the United States government's trial registry yourself. Search afamelanotide and 23 studies come back, every one listing a Clinuvel company as lead sponsor. Search by term and by intervention for melanotan I, melanotan-1 and melanotan 1, six searches in all, and every one comes back with zero records.

One check this project now runs on everything. The melanotan II entry documented eight fabricated registrations filed under a single sponsor at one Shenzhen hospital. I ran that query again and got the same eight, covering tesamorelin, GHK-Cu, tirzepatide, retatrutide, melanotan II, BPC 157, MOTS-c and TB-500. None names melanotan I or afamelanotide. The forgery check here came back negative, and nothing on that list should be read across to this compound.

FDA's list of bulk drug substances that may present significant safety risks names Melanotan II, citing case reports of melanoma, encephalopathy and priapism. I searched that page for melanotan I and for afamelanotide and found neither. And in 2024 the licence holder applied to extend SCENESSE to adolescents, narrowed the request to ages 15 to 17 on data from 7 of them, then withdrew it, the regulator's provisional opinion being that the medicine could not have been authorised in adolescents for want of sufficient evidence on effectiveness, safety and dose.

08What could go wrong

The implant's trial safety record is unremarkable, and that should be said first. Across three placebo controlled trials in 244 adults with the disease, 125 received SCENESSE and 119 received a dummy implant: implant site reactions 21 percent against 10, nausea 19 against 14, moles 4 percent against 2. The European label pools 425 patients and reports mostly mild reactions at similar rates, without saying how many of the 425 received the drug.

The pigment is the point, and pigment is what a dermatologist watches. A mole, listed as melanocyte naevus, sits in the European adverse reaction table under common, defined there as between 1 in 100 and below 1 in 10 patients, and both labels recommend, recommend being their word rather than require, a full body skin examination every six months, because the drug darkens existing moles and freckles as a direct consequence of how it works. In the pivotal trial one patient withdrew with a melanoma in situ, a skin cancer still confined to the surface layer, which the assessment report places in the placebo group, and one withdrew after two implants with a mole showing mild abnormality, which the report calls unlikely related to study drug and does not assign to an arm.

The American regulator did not treat the question as closed. As a condition of approval it required an eight year registry of treated patients with two primary adverse events of interest, skin cancer and implant site reactions, final report due March 2031. Its label also states that carcinogenicity studies have not been conducted with SCENESSE, a waiver having been granted in March 2017, and the reason the same review gives elsewhere is that there is no accurate animal model to address the potential of afamelanotide to induce melanomas. All of that concerns a drug given three or four times a year in Europe and five at most in the American review, under a specialist's eye, and none of the label's other guards travels with a grey market vial. A 2026 systematic review does say unregulated melanotan I and II use has caused rhabdomyolysis, renal infarction and priapism (PMID 41890775), but the individual published cases I could trace behind those words are melanotan II cases, as is the one published chemical analysis of internet bought tanning peptide I found.

09What nobody knows

Whether what ships is afamelanotide. My searches for a purity or content analysis of vials sold as melanotan I came back with nothing usable, so the identity of the powder is untested rather than confirmed.

Whether a weekly injection does anything. The monthly rate is close to the label's, the delivery is not, and the persistence of pigment hides the question from the person injecting.

Whether the 16 mg was ever established. The European label says dose finding studies have not been conducted; FDA's review of the same product says the dose is supported by dose response in three phase 1 studies. I could not reconcile them.

Whether repeated pigment stimulation raises skin cancer risk. Carcinogenicity studies were waived, the review says there is no accurate animal model for the question, and the registry required in their place does not report until 2031.

What happened to the tanning programme. Injected tanning was tested in healthy volunteers four times between 1997 and 2006, with results that look positive, and then that indication does not appear again in anything I searched.

10What the selling rests on

The chemistry is honest, and that is what makes this one hard. A vendor page can point at PubChem, point at the FDA label, and be telling the truth about the molecule. Everything after that sentence is transferred from a rod to a vial.

The transfer costs more than it looks. The approved thing holds a low flat level for under a week, then nothing for seven weeks, at most four or five times a year, in a patient with a diagnosed disease, placed by a physician the manufacturer trained. The circulating thing is a spike that clears within a day, self administered, weekly, in a healthy person chasing colour. The monthly arithmetic matches. Nothing else does. And the approval lending its authority to it is the thinnest kind there is: exceptional circumstances, one pivotal trial after two others were dropped following an inspection, an effect measured in pain free hours rather than tan depth, significance on a one sided test, a headline effect size the assessors themselves filed under post hoc analyses, and seven members of the committee signing a divergent position against it.

Open the European assessment report for Scenesse, EMA/CHMP/601433/2014, and read two things: the section headed post hoc analyses, which is where the 24 hour figure actually lives, and the final page, which is a signed divergent position by seven members of the committee that recommended the approval.

Frequently asked

Is melanotan I the same thing as afamelanotide?+

By every identifier I could check, yes. One PubChem record, CID 16197727, carries Afamelanotide, Melanotan I and Melanotan-1 among its synonyms, and its molecular formula and weight match the ones printed in the description section of the FDA label for SCENESSE. What differs is the product, not the molecule. The approved product is a 16 mg rod placed under the skin by a trained physician every two months in patients with a rare light sensitivity disease, and that is a label figure reported here rather than a recommendation.

What is melanotan I actually approved for?+

One disease, in both jurisdictions. The European label's indication section is a single sentence: prevention of phototoxicity in adult patients with erythropoietic protoporphyria, the rare disease both labels describe in terms of phototoxic reactions, meaning damage triggered by light. The American indication is to increase pain free light exposure in adults with a history of phototoxic reactions from the same disease. What the pivotal trials measured was hours spent in sunlight without pain. Neither approval mentions tanning, cosmetic use or healthy adults.

How big was the effect in the trial the European approval rests on?+

Small, and its status matters more than its size. CUV039 enrolled 93 adults, of whom 48 received the implant and 45 a dummy. On the protocol primary endpoint, analysed on the 46 and 43 patients the European report tabulates, the medians were 69.4 hours against 40.8 hours of pain free sunlight over six months, significant only on a one sided test at 0.044, the kind that asks only whether the drug beat the dummy and not whether it did worse. The 24 hours of extra pain free sunlight that gets quoted, and its range of 0.3 to 50.3 hours, comes from a method the assessment report says was specified after the data were in, and the report prints that figure under a heading for post hoc analyses.

Is melanotan I safe?+

The implant's trial record is unremarkable and should be reported as such: across three vehicle controlled trials in 244 adults with the disease, 125 received the drug and 119 received a dummy implant, with implant site reactions in 21 percent against 10 percent and nausea in 19 against 14. The concerns are about pigment and about who is holding the vial. Darkening of existing moles is on both labels, both labels recommend a full body skin examination every six months, the FDA label states that carcinogenicity studies have not been conducted with SCENESSE, and the FDA required an eight year registry of treated patients as a condition of approval, with two primary adverse events of interest, skin cancer and implant site reactions, whose final report is due March 2031. None of that record describes daily or weekly self injection in healthy adults, which I found no study of.

Where does the 2 mg a week figure come from?+

From arithmetic on the approved implant, done on a vendor page, and reported here as convention rather than as a recommendation. That page states the trials used a 16 mg implant every 60 days, converts it to 8 mg a month, then offers 2 mg a week as the same monthly rate. The two match on a four week month; across a calendar year they are 104 mg against about 97 mg. The rate is close and the delivery matches nothing that was studied, since the approved rod releases most of its content over the first two days and is absorbed by the body over 50 to 60 days. I found no published study of a weekly injection of this peptide in people.

Was melanotan I named in the fabricated trial registrations?+

It was not. The eight registrations this project's melanotan II entry identifies as fabricated, filed under one sponsor at a single Shenzhen hospital, cover tesamorelin, GHK-Cu, tirzepatide, retatrutide, melanotan II, BPC 157, MOTS-c and TB-500. I re-ran that sponsor query and got the same eight records, and none of them names melanotan I or afamelanotide. Searching the registry by term and by intervention for the three spellings of melanotan I returned zero records each time, and searching afamelanotide returned 23 studies, every one of them sponsored by a Clinuvel company.

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