Our Melanotan II pen holds 20 mg in 3 ml as a pre-loaded multi-dose pen. Before anything else is said about it, two facts should be on the table: melanotan II holds no marketing authorisation anywhere in the European Union, and the compound most often confused with it, afamelanotide, is an authorised medicine that behaves differently at the receptor level. For every batch we publish the independent certificate of analysis on our certificates page, so what is in the pen rests on the laboratory’s figures rather than on our word. Nothing on this page claims what the compound does for you.
The evidence base here is unusually thin for a compound this widely sold. There is no published human dose-ranging trial. What exists in the peer-reviewed literature is largely case reports, and several of them describe serious harm. We say that plainly because a page that omitted it would be misleading. Systemic toxicity and rhabdomyolysis after melanotan II injection. PMID 23121206; Melanoma associated with the use of melanotan-II. PMID 24355990; Change in moles linked to use of unlicensed “sun tan jab”. PMID 19174439; Melanotan II as a possible cause of renal infarction. PMC7148395; Oral mucosal changes associated with melanotan II injections. PMC12942211; EMA: Scenesse (afamelanotide) EPAR
This section covers four things that matter when assessing a melanotan II product: what the molecule is, why its receptor selectivity is the central issue, what the published human record actually contains, and what its regulatory status is across Europe.
What melanotan II is
Melanotan II is a synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH), the body’s own signalling peptide for melanin production. It is a cyclic peptide, not a copy of α-MSH, and the structural changes that were made to it produce a longer-acting and more potent molecule than the natural hormone.
It acts on melanocortin receptors. The pigmentation effect people are after runs through MC1R, which sits on melanocytes in the skin. That much is straightforward pharmacology and is not in dispute.
The complication is what else it acts on. Our overview page What is Melanotan II? covers the background; this section deals with the parts that determine whether a specific product can be evaluated at all.
Selectivity is the whole question
Melanotan II is not selective. Alongside MC1R it activates MC3R and MC4R, and MC4R sits in central pathways governing appetite and sexual function. This is not an incidental detail. It is the mechanistic explanation for effects that have nothing to do with skin, and it is the single largest difference between melanotan II and its authorised relative.
A compound that hits three receptors in a family cannot be described as a tanning agent with side effects. It is a multi-receptor melanocortin agonist, one of whose effects is pigmentation. Any product description that presents only the MC1R activity is describing a fraction of the pharmacology.
We compare the two molecules directly on Melanotan II vs Melanotan I.
The authorised relative: afamelanotide
Afamelanotide, also called melanotan I and marketed as Scenesse, is MC1R-selective, and it is an authorised medicine. The European Medicines Agency has authorised it in the EU since 22 December 2014, for the prevention of phototoxicity in adults with erythropoietic protoporphyria, a rare inherited condition in which sunlight causes severe pain. It received orphan designation on 8 May 2008.
Three features of that authorisation are worth stating because they are routinely misrepresented:
- it was granted under exceptional circumstances, because placebo-controlled trials in this indication are difficult to run: patients are unwilling to expose themselves to sunlight;
- the product is a subcutaneous implant, placed by a healthcare professional roughly every two months, not a self-administered injection;
- the authorised indication is a rare disease, not cosmetic tanning.
Melanotan II is not an over-the-counter version of this. It is a different molecule with a broader receptor profile and no authorisation anywhere in the EU.
What the human evidence actually consists of
There is no published human dose-ranging trial for melanotan II. No study has established a dose, a schedule, or a safety margin. Figures that circulate online are not traceable to controlled research, and we do not publish any.
The peer-reviewed human record is dominated by case reports, and their content is not reassuring. Published cases describe systemic toxicity with rhabdomyolysis and renal dysfunction following self-administration, renal infarction, changes in existing melanocytic naevi, and melanoma diagnosed in users. A separate case describes mucosal melanoma in a user of a melanotan II nasal spray.
Case reports cannot establish causation, and that point cuts both ways. They cannot prove melanotan II caused these outcomes, and they equally cannot be used to argue the compound is safe. What they do establish is that serious events have been observed and documented in users, which is more than can be said for any published evidence of benefit.
Reported milder effects in the literature and in regulator records include nausea, flushing, loss of appetite, and spontaneous yawning and stretching. Serious reported events include priapism and hypercortisolism.
Regulatory status across Europe
Melanotan II holds no marketing authorisation in the European Union or the United Kingdom. In the UK its sale is illegal, and the MHRA has repeatedly warned against unlicensed products marketed for tanning; the agency holds adverse-reaction reports for melanotan II products.
This is a genuinely different legal position from most compounds in our catalogue. Several are investigational — never approved, but not the subject of standing regulator warnings. Melanotan II is one where regulators have issued specific public warnings about the product category, and that distinction belongs on the page rather than buried.
The pigmentation and skin-cancer question
The most important open question is one that a tanning-focused product description tends to skip. Melanocortin signalling drives melanocyte activity, and several published cases describe changes to existing moles or melanoma diagnosed in melanotan II users.
There is no controlled evidence establishing whether melanotan II increases melanoma risk, and there is no controlled evidence establishing that it does not. In a compound whose mechanism directly stimulates the cell type from which melanoma arises, the absence of long-term safety data is itself the finding. Anyone considering this compound should discuss existing moles and skin-cancer risk with a qualified clinician first, and any change to a mole warrants prompt medical assessment regardless.
What the certificate for your batch shows
An independent laboratory tests every batch for identity by mass spectrometry, for purity by HPLC and for sterility; identity is confirmed by mass rather than by a retention time alone. The certificate for your batch shows the HPLC purity figure and the concentration of the cartridge, in mg/ml and as total mg per 3 ml, under the batch number printed on the pen. The QR code on the pen resolves to the certificate for that batch rather than to a sample report, so matching the certificate to the pen in your hand takes a moment.
What those figures do and do not prove is worth understanding before you read one: what a purity percentage shows, how identity is established by different methods, and what independent testing means in practice. None of it is clinical evidence. It tells you what is in the pen, not how your body responds to it.
Our position on this compound
We supply melanotan II as a pre-loaded pen, tested per batch by an independent laboratory, and in stock and shipping now. We are not going to pair that with claims about tanning outcomes, because no controlled human evidence supports them, and we are not going to omit the case-report literature, because it exists.
If the honest summary (no authorisation, no dose-ranging trial, documented serious case reports, and a mechanism that stimulates melanocytes) makes this compound unattractive, that is the summary doing its job. Related reading: peptides for skin, cosmetic peptides and how to read a certificate of analysis.
