All compounds

Melanotan II

Also sold as MT-II, MT2, melanotan 2, the Barbie drug. Synthetic analogue of α-melanocyte-stimulating hormone (α-MSH).

Serious risk (4 of 5)

Melanotan II tans you without the sun, which is genuinely what people want from it — by driving the exact cells that become melanoma, in people who then find their moles have changed and cannot tell whether it matters.

What it is

Melanotan II is a synthetic analogue of α-melanocyte-stimulating hormone, the body’s own signal for producing melanin. It came out of research at the University of Arizona in the 1980s, where the original idea was a defensible one: if you could make people tan without ultraviolet exposure, you might reduce skin cancer rather than cause it.

That programme produced two things. One is bremelanotide, a related peptide that went through proper clinical development and is an approved prescription medicine for low sexual desire in premenopausal women. The other is melanotan II, which never completed development, was never approved anywhere, and is sold online as an unregulated peptide.

That split is worth sitting with. It is not that this chemistry is fringe or unstudied in principle — a sibling compound made it all the way through. Melanotan II is the one that did not, and it is the one being injected by people at home.

It is sold as vials of powder for injection, and increasingly as nasal sprays. In the United Kingdom, Ireland, Australia and much of Europe, selling it is illegal, and regulators have issued repeated warnings.

What it actually does

Melanotan II activates melanocortin receptors, and it does so less selectively than the body’s own signal. Three effects follow, and all three are reasons people take it.

It tans you. This is the main one and it works — deeply, and with far less sun exposure than would otherwise be needed. For someone with pale skin who burns rather than tans, this does something that nothing else available does.

It suppresses appetite, noticeably.

It substantially increases sexual arousal, and in men frequently causes spontaneous erections. This is not an incidental side effect — it is the effect that the sibling compound bremelanotide was approved for. People often start taking melanotan II for the tan and continue partly for this.

So: it works. It does three things people want, and unlike much of what is sold online, the effects are unambiguous and arrive quickly. That is why warnings about it have so little traction, and it is why this page leads with what it does rather than with what it costs.

What the evidence actually shows

On efficacy: it plainly works, and there is no modern trial evidence. The tanning effect is not in doubt — it is visible. But melanotan II itself never completed a development programme, so there is no controlled safety data in the way there is for the approved sibling compound.

On harm: the evidence is case reports, and it is unusually consistent.

Since 2009 there has been a steady international literature — from the United States, Ireland, Germany, Spain, the Netherlands and elsewhere, from unrelated clinicians who were not looking for each other’s findings — describing the same thing: people developing new moles, and existing moles changing, during melanotan use. Some of these are described as eruptive, meaning many appeared over a short period. Some, on examination, were dysplastic — atypical in ways that matter.

There are also reports of melanoma in people who used it, including a recent report raising melanotan II nasal spray as a possible factor in a melanoma of the oral mucosa.

Here is where we need to be precise, because it is the crux of the page. Case reports cannot establish that melanotan II causes melanoma. The people using it are disproportionately people who like being tanned, which means disproportionately people with more sun exposure and more baseline risk. There is no cohort study, no rate, and no proof of causation. We are not telling you melanotan II has been shown to cause cancer, because it has not been.

What is established is narrower and still serious. The compound stimulates melanocytes — the exact cell type from which melanoma arises. Under that stimulation, moles change: they darken, they grow, new ones appear. That is not disputed and it is directly observable.

And that produces a specific, concrete problem regardless of whether the compound is carcinogenic. Detecting melanoma early depends almost entirely on noticing that a mole has changed. Melanotan II makes your moles change. It removes the signal that skin cancer screening depends on, in someone who has just acquired a lot of new pigmented lesions to keep track of.

The risk profile

Serious risk (4 of 5) — Documented harm in humans that is severe, common, or hard to see coming.

What going wrong looks like from the inside

The problem is that the thing going wrong looks exactly like the thing working.

You inject it, and over days your skin darkens. Freckles come up. Moles you already had get darker and more defined. New small pigmented spots appear, often on the trunk. Every one of those changes is the compound doing precisely what you bought it to do, and every one is also what dermatologists ask people to watch for.

There is no way, from inside, to separate them. A mole that has darkened because melanotan stimulated it and a mole that has darkened because something is wrong with it look the same to you in a mirror. That is the failure mode: not a symptom you might miss, but the deliberate destruction of your ability to interpret the symptom.

The nearer-term effects are more obvious. Nausea and vomiting are common in the first while and are the usual reason people stop. Facial flushing. Yawning and stretching in an odd, characteristic way. Darkening of skin in patches and of existing scars. Prolonged and sometimes painful erections, occasionally severe enough to need treatment — a persistent erection lasting several hours is a medical emergency, because it can cause permanent damage, and it is a genuinely embarrassing thing to present with that people delay on.

The practical thing to do, whichever way you decide: get a proper skin check, by a dermatologist, and get photographs of your moles. If you have used melanotan, having a baseline from before or early in use is worth a great deal later, when the question becomes “has this changed?” and you have no way to answer it. If you notice a lesion that is changing faster than the others, bleeding, itching, or has an irregular edge or more than one colour, that is worth a proper look regardless of what caused it.

Interactions and combinations

Melanotan II is not a central nervous system depressant and does not carry the respiratory-arrest risk of the opioid and GABA compounds on this site.

The combination that genuinely matters is melanotan II and ultraviolet exposure. Many people use it precisely so that they tan faster in the sun or on a sunbed, which means the compound and UV are being applied to the same skin at once. A tan is not protection, and stimulating melanocytes while also irradiating them is the worst version of this decision.

Erectile dysfunction medication taken alongside it raises the risk of a prolonged erection needing treatment.

The other combination worth naming is with existing risk factors rather than other drugs: fair skin, red or blond hair, many moles, a history of sunburn, or any family history of melanoma. Those are exactly the people most drawn to a compound that tans them, and exactly the people for whom losing the ability to monitor their moles matters most.

Injecting an unregulated peptide carries its own infection risk, independent of the molecule.

If you’re already using it

There is no withdrawal and no reason to come off gradually. Stopping is stopping. The tan fades over weeks to months, and the increased appetite returns.

The single most useful thing you can do is get your skin examined by a dermatologist, and say that you have used melanotan. That last part is not optional. A dermatologist assessing a young person with numerous recently-appeared moles will reason completely differently if they know why, and they may want to photograph and track rather than biopsy several lesions at once. Not saying it can lead to unnecessary excisions — or worse, to a changing lesion being attributed to the drug when it should not have been.

Get baseline photographs, either through the clinic or on your own phone, in consistent light. This is the thing that makes the next few years answerable.

Do not use it to tan faster in the sun or on a sunbed. If you are going to use it at all, the entire original rationale was to avoid UV, not to amplify it.

Treat an erection lasting more than a few hours as an emergency and go in. It is a known effect of this class of compound, they will have seen it, and waiting risks permanent damage.

And keep going to skin checks after you stop. The moles that appeared do not disappear, and the monitoring problem you created outlasts the tan.

This page has not yet been reviewed by a clinician. It was written from the published literature and every claim is cited, but no named medical professional has checked it. We say so here rather than let a missing byline read as an implicit one.

Last reviewed 7 September 2026. Found something wrong? Corrections are published, not silently edited.