If you only want the short version. Melanotan II is a lab-made tanning drug, sold online as melanotan 2, MT-2 or a tanning injection, and called the Barbie drug in press coverage. No country has approved it for any use.
It works by switching on the cells that make pigment. Those are the same cells your moles are made of, and the most commonly reported problem is moles that darken, change shape, or appear where there were none.[^2]
A 2017 medical review found four published cases of melanoma growing in a mole during or soon after melanotan use. The same review says a firm link is not proven.[^2] So this is not proof. It is a good reason to get your moles checked.
The most common side effects are nausea, flushing, appetite loss and spontaneous erections. The same mechanism produces all of them, and the tan. A few effects are emergencies, and those are listed first.
Stop and get help now if
A painful erection lasting more than four hours
This is called priapism and it is a medical emergency, not an embarrassment to wait out. In a published case, a man who injected melanotan II went to hospital with ischaemic priapism. Drainage and injected medication both failed, he needed surgery to relieve it, and he was left with erectile dysfunction and scarring inside the penis.[^4] A second published case describes a man whose erectile function had not returned four weeks later.[^4] Delay is what causes the permanent damage.
Severe muscle pain with dark or cola-coloured urine
These are signs of rhabdomyolysis, where muscle tissue breaks down and floods the kidneys. A published case involved a man who injected six times the amount he intended and spent three days in intensive care with a racing heart, muscle enzyme levels near 18,000, and kidney injury.[^3]
A severe headache with vision changes, confusion, or a seizure
A syndrome called PRES, involving swelling in the brain, has been reported after melanotan II use.[^7]
Chest pain, a pounding heart, or a sudden rise in blood pressure
One published case describes a previously healthy man who developed hypertension and a kidney infarction after months of use.[^7]
A mole that has changed
This is not an emergency in the four-hour sense, and it is the one that matters most. A mole that has grown, darkened, changed shape, developed uneven edges, or started to itch or bleed needs a dermatologist. Take a photograph and book the appointment.
Anything short of an emergency that still has you guessing, our guide on when an injection site reaction means stop and get seen sorts most of it.
Three drugs, one prefix
Searches for melanotan return three different compounds, and only one of them is what people are buying.
Melanotan I is afamelanotide. The FDA approved it in 2019, sold as Scenesse, for adults with erythropoietic protoporphyria, a rare condition causing severe pain on light exposure.[^1] It is a real, tested, prescription medicine for a disease almost nobody has.
Melanotan II is approved nowhere. No regulator anywhere has cleared it for any use, and no manufacturer has ever submitted it for review. It is the one sold online for tanning.
Bremelanotide is Vyleesi. It was derived from melanotan II and approved in 2019 for low sexual desire in premenopausal women.[^1] The sexual effects that melanotan II users report are the same pharmacology, developed into a separate approved drug.
Afamelanotide matters to this page for one reason. A properly tested melanocortin drug exists, went through trials, and reached the market. Melanotan II never entered that process at all.
It works
Melanotan II does produce pigment. That has never been the disputed part.
The argument is about what arrives alongside the pigment, and about what the pigment fails to do. Australia's medicines regulator states the second half plainly: no tan, artificial or real, protects skin against sun damage, and melanotan will not protect against UV the way sunscreen does.[^12]
The side effects are the mechanism
Melanotan II activates the melanocortin receptors, and it does not activate them selectively. The same signalling that darkens skin also runs through receptors involved in nausea, appetite, blood pressure and sexual arousal.[^2]
This explains something that confuses people who read forum posts. The nausea, the flushing, the appetite drop, the spontaneous erections and the tan all come out of one mechanism firing at once, with the tan being the output people wanted. Nobody has found a way to keep the pigment and drop the rest, which is the problem afamelanotide was designed to solve by targeting a single receptor.
The mole problem
Melanotan II stimulates melanocytes, the cells that produce pigment. Melanocytes are also the cells that moles are made of, and the cells that melanoma arises from.
The 2017 review that dermatologists still cite pulled the published case reports together. It found a consistent pattern: existing moles darkening, new moles appearing, and dysplastic nevi, meaning moles with abnormal features. It also identified four case reports of melanoma developing in an existing mole during or soon after melanotan use.[^2]
Those case reports have limits. Four of them is not an epidemiological study. The same review states directly that conclusive evidence linking melanotan to melanoma is lacking.[^2] A separate line of argument holds that people who inject a tanning drug are also more likely to seek sun, which would raise melanoma rates independently. Nobody has run the study that would settle it, because there is no sponsor to run a safety trial for a drug with no owner.
None of that clears the drug. A plausible mechanism and a set of consistent case reports sit on one side, with no controlled evidence on the other. A dermatologist quoted in 2026 described treating patients with severe dysplastic nevi and melanoma in situ while on the drug.[^8]
In 2025 a case report extended the concern past skin. A 22-year-old woman developed a malignant melanoma in the lining of her mouth after using melanotan II nasal spray.[^6] A single case proves nothing on its own, and it is the first published suggestion that the site of exposure matters.
Who is at highest risk
Everything above changes very little for someone with olive skin and three moles. It changes a great deal for other people, and the page has been treating both the same way until now.
The features that raise melanoma risk are well established. Skin that burns before it tans, fair or red hair, a high mole count, moles that are already atypical, a personal history of melanoma, a family history of it, previous sunbed use, and a suppressed immune system from illness or medication. Anyone carrying several of those starts from a different baseline, and a drug whose entire purpose is stimulating melanocytes sits badly against that baseline.
The clearest argument for taking this seriously comes from the approved version. Afamelanotide is selective, tested, prescribed and given under supervision, and its labelling still warns that it may darken skin and recommends a full body skin examination twice a year.[^1] Those precautions attach to the careful version of this pharmacology. No vendor selling the uncontrolled version suggests anything comparable.
There is also a detection problem, which is separate from the risk itself. The Skin Cancer Foundation's July 2026 statement notes that rapid changes in moles and pigmented lesions can make skin cancer harder to detect.[^11] A drug that darkens everything at once takes away the contrast a dermatologist depends on.
Darker skin is not exempt. Australia's medicines regulator lists increased moles and freckles among the reported effects,[^12] and pigment that arrives unevenly is a frequent complaint. What people report being unhappy with is usually patchiness.
The nasal spray
Injection was the original route. Nasal spray is what drove the recent surge, because it removes the needle and with it the main psychological barrier.
It removes the measurement too. A vial and a syringe give you a number, even if the number is unreliable. A spray gives you a squeeze. Dosing errors were already common with melanotan, and a Dutch poisons centre report attributed that partly to users having to prepare and calculate their own solutions.[^3] A spray hides that problem instead of fixing it.
The trend is also young. An analysis of tanning content on TikTok found that the overwhelming majority of videos portrayed tanning positively, with a small but growing share specifically about melanotan II by spray, injection or both.[^5] TikTok has since banned several tanning hashtags, and dermatology journals have published repeated warnings through 2026.[^5][^8]
What is actually in the vial
Two published analyses have examined the products themselves.
One laboratory study bought melanotan II vials from three online shops and analysed what was inside them. The vials were generally weaker than their labels claimed, and they contained impurities.[^9] A 2022 dermatology study looked at the sellers instead, surveying online distributors of these analogues and documenting inconsistent labelling and marketing claims.[^10]
Neither finding is unique to melanotan. What makes it worse here is the interaction with the effects listed at the top of this page. The rhabdomyolysis case came from a dose six times larger than intended, in a compound where the difference between a tanning dose and a toxic one is not established, using a vial nobody had verified. Our guide on reading a certificate of analysis covers what a vendor can and cannot prove about the powder they sold you.
Does it protect you from the sun?
The sun-protection claim does more selling than any other, and it has the least behind it.
Pigment does carry some protection, and that is where the claim starts. It is not the same as evidence that this drug reduces skin cancer risk or prevents burning at any useful level, and no trial has shown either. Australia's regulator advises people who have used melanotan to stop and speak to a health professional, and states directly that artificial pigmentation will not protect against UV the way sunscreen does.[^12] Afamelanotide does have photoprotection data, and that data belongs to a different molecule, tested in a rare light-sensitivity disease, under medical supervision.[^1]
People using melanotan II still burn. Several also report using it alongside sunbeds and sun exposure to develop the tan faster, which stacks a documented carcinogen on top of an untested drug.
Where it stands legally
Melanotan II has no approval anywhere in the world. In the United States it is an unapproved new drug, and the FDA has issued warning letters to companies selling it. The UK medicines regulator classifies it as an unlicensed medicine and warned the public about it in 2009. In Australia it is illegal to supply melanotan in any form without a prescription, and illegal to advertise it to the public, which the regulator notes applies to social media influencers as much as to sellers.[^12] Multiple national health bodies have issued safety warnings, a point the 2017 review notes explicitly.[^2] The Skin Cancer Foundation issued its own warning in July 2026.[^8]
One development is going to be presented to you as good news. The FDA intends to consult its compounding advisory committee on melanotan II by the end of February 2027, alongside GHK-Cu, dihexa, LL-37 and PEG-MGF. Vendors will present that as a step toward legitimacy. Our coverage of that meeting and of the July 2026 vote explains what a favourable recommendation has historically been worth, which is less than it sounds.
If someone is going to use it anyway
Realistically, some readers of this page have already ordered it. Nothing below makes it safe.
Get your moles mapped first, and by a dermatologist. Nothing else on this list changes an outcome as much. A documented baseline is what makes a later change visible, and without one you are comparing a mole to your memory of it.
Photograph your own moles monthly, with a ruler in frame. It costs nothing and it is the evidence a dermatologist will ask you for.
There is no established human dose. The community numbers circulating for loading and maintenance have no clinical trial behind them. Early human studies used supervised weight-based dosing in research settings, which is a different thing from a fixed number on a forum.
Do not stack it with sunbeds. The most common protocol advice online pairs the drug with UV exposure to speed up pigmentation, which combines an unapproved drug with an established carcinogen.
Never share a vial or a needle. Multi-dose vials shared between people are an infection route, and this compound is often bought and split socially.
Tell the doctor what you took. The reason people do not is embarrassment, and a dermatologist who does not know why the pigment changed is working with a piece missing. The appointment itself is a few minutes of someone looking at your skin under a light.
Stop and get seen for anything on the emergency list. Bring the vial and tell the clinician what you took, because they cannot treat what they have not been told about.
The limits of what is known
Your individual melanoma risk is not something this page can estimate. Skin type, family history, mole count and sun history matter more than anything written here, and a dermatologist can assess all four in one appointment.
The odds of a serious reaction are unknown too, because the safety trial that would produce that number has never been run. Everything in the emergency section comes from case reports, which record that something happened without establishing how often.
And nothing here can tell you what is in the vial you bought.
Common questions
Is melanotan II legal to buy?
Selling it for human use is illegal in the United States, the United Kingdom and Australia, among others. It is sold anyway, labelled for research use, which is a label about the sale and not a statement about safety. Our guide on what research use only actually means covers the distinction.
Is the nasal spray safer than injecting?
There is no evidence for that, and two reasons to doubt it. The spray removes any ability to measure what you took, and the one published melanoma of the mouth lining followed nasal use.[^6]
My mole got darker. Is that the drug working or a problem?
Both are described in the literature, which is why it needs a professional look. Darkening of existing moles is the most commonly reported cutaneous effect and also an early melanoma sign.[^2] A dermatologist can tell the difference by looking at it.
Will the tan fade if I stop?
Pigment produced this way fades over weeks to months. Reported mole changes have not always reversed on stopping, and that is the part to weigh before starting.
Does it help with weight loss or sex drive?
Both effects are real and both come from the same non-selective receptor activity as the tan.[^2] Approved drugs exist in both categories, tested for those purposes, with known doses and a prescriber attached.
Is melanotan II the Barbie drug?
Yes. The nickname comes from press and social media coverage, usually describing the combination of a deep tan, appetite suppression and the compound's sexual effects. It refers to melanotan II, and occasionally to bremelanotide, which is the approved drug derived from it.
Is melanotan II the same as melanotan I?
No, and the difference is large. Melanotan I is afamelanotide, an FDA-approved prescription implant for a rare light-sensitivity disease. Melanotan II is a different molecule, approved nowhere, and it is the one sold online. Our comparison of the two covers where the confusion comes from.
Can you buy melanotan II legally in the UK or Australia?
No. UK regulators classify it as an unlicensed medicine. In Australia it is illegal to supply in any form without a prescription, and illegal to advertise to the public, which the regulator states applies to social media influencers as well as sellers.[^12] It is sold anyway, usually labelled for research.
How long does it stay in your system?
Nobody has published proper pharmacokinetic data for melanotan II in humans, so there is no reliable answer. The pigment it produces fades over weeks to months, and that is a separate question from how long the drug itself is present.
I used it years ago and stopped. Should I do anything?
A skin check is reasonable, especially if you have never had one. Melanoma risk from any exposure accumulates over years, and a baseline is useful whatever the cause.
Sources
[^1]: FDA. News release announcing approval of Scenesse (afamelanotide), 8 October 2019, carried verbatim on the newswire; and FDA, VYLEESI (bremelanotide injection) prescribing information, NDA 210557, approved 21 June 2019. Regulatory. Scenesse was approved 8 October 2019 to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria. Vyleesi was approved 21 June 2019 for acquired, generalised hypoactive sexual desire disorder in premenopausal women; its labelling includes skin hyperpigmentation among its warnings. The Scenesse prescribing information's statement that the implant may induce skin darkening, and its recommendation of a full body skin examination twice a year, are taken from two independent professional summaries of the label rather than from the label document itself. [^2]: Habbema L, Halk AB, Neumann M, Bergman W. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. International Journal of Dermatology 2017;56(10):975-980. Peer-reviewed review, abstract read at source. States that unregulated use of melanotan I and II is associated with cutaneous complications, particularly melanocytic changes in existing moles and newly emerging dysplastic nevi; that four case reports describe melanomas emerging from existing moles during or shortly after use; that conclusive evidence linking the two is lacking; and that multiple national health organisations have issued safety warnings. Also notes afamelanotide as the only approved analogue. [^3]: Nelson ME, Bryant SM, Aks SE. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clinical Toxicology 2012;50(10):1169-73. Peer-reviewed case report, abstract read at source. A 39-year-old man injected 6 mg subcutaneously, which he stated was six times his intended starting dose, and presented two hours later with diffuse body aches, sweating and anxiety, blood pressure 151/85, heart rate peaking at 146 bpm. Outcome included rhabdomyolysis and renal dysfunction. The peak creatine kinase figure near 18,000 and the three-day intensive care stay appear in secondary summaries of this case, not in the abstract read here. The Dutch Poisons Information Centre consultation counts and the observation that dosing errors are common because users prepare and calculate their own solutions come from associated correspondence in the same journal. [^4]: Cordon BH, et al. Melanotan Tanning Injection: A Rare Cause of Priapism. Sexual Medicine 2021;9(1):100298. Peer-reviewed case report, abstract and introduction read at source. Describes acute ischaemic priapism after a 2 mg subcutaneous injection of melanotan II, initially managed with cavernosal aspiration, irrigation and intracavernous phenylephrine without achieving detumescence, then treated operatively with penoscrotal decompression, with subsequent erectile dysfunction and corporal fibrosis. The paper defines priapism as an erection lasting longer than four hours unrelated to sexual stimulation, and notes that ischaemic priapism can progress to fibrosis of cavernosal tissue and erectile dysfunction. It records only two prior published cases of melanocortin-induced priapism, one of which is the separate case managed without surgery in which erectile function had not recovered at four-week follow-up. [^5]: Kream E, et al., analysis of tanning-related content on TikTok, and subsequent dermatology commentary on nasal tanning sprays. Peer-reviewed analysis and clinical commentary, read via search-result excerpts. The TikTok analysis found that the large majority of tanning-related videos portrayed tanning positively, with a small subset specifically covering melanotan II by nasal spray, injection or both. Exact counts (441 of 488 videos, 12 of 441) appear in the commentary summarising it and were not verified against the original paper. [^6]: Yassin Alsabbagh A, Bhujel N, Singh RP. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? International Journal of Oral and Maxillofacial Surgery 2025;54(9):806-808. Peer-reviewed case report, citation confirmed across two independent sources; abstract not consulted directly. Describes a 22-year-old woman who developed an anterior maxillary mucosal malignant melanoma after using melanotan II nasal spray. [^7]: Peters, CEN Case Reports 2020 (renal infarction with new hypertension after approximately six months of subcutaneous use) and published case reporting of posterior reversible encephalopathy syndrome following melanotan II use. Peer-reviewed case reports, citations captured from secondary summaries; abstracts not read at source. PRES is independently listed among reported harms in consumer-facing academic commentary, which describes brain swelling alongside rhabdomyolysis and priapism. [^8]: The Conversation, March 2026, academic-authored; Dermatology Times, August 2026, quoting a dermatologist describing severe dysplastic nevi and melanoma in situ in patients using the drug; and reporting of the Skin Cancer Foundation warning issued 7 July 2026. Expert commentary and press. Read via search-result excerpts. [^9]: Breindahl T, Evans-Brown M, Hindersson P, McVeigh J, Bellis M, Stensballe A, Kimergård A. Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug Testing and Analysis 2015;7(2):164-172. Peer-reviewed laboratory analysis, abstract read at source. Confirms that vials were purchased from three online shops and analysed for identity, content and purity by validated LC-UV and tandem mass spectrometry methods. The abstract does not state the results. The qualitative finding that most vials were understrength and contained impurities is corroborated by a later academic paper citing this study. Specific figures circulating in secondary sources (4.32 to 8.84 mg against a 10 mg label, impurities at 4.1 to 5.9% by mass) were not verified against the full text and are deliberately omitted here. [^10]: Hadeler E, et al. Evaluation of synthetic alpha-melanocyte-stimulating hormone analogs: an observational study of unregulated, online-available drugs. Journal of the American Academy of Dermatology 2022;87(1):199-201. Peer-reviewed observational study, citation verified at PubMed; abstract content not displayed. Characterised here only as an examination of online distributors documenting inconsistent labelling and marketing. The figures reported elsewhere (35 distributors, 65.7% labelled research only) come from secondary summaries and are omitted. [^11]: The Skin Cancer Foundation. The Skin Cancer Foundation Issues Warning Regarding Melanotan II, 7 July 2026. Non-profit medical organisation statement, read at source. Discourages use of melanotan II and other unapproved tanning agents, notes that it has no FDA approval for any use and that its safety has not been established, that case reports document melanoma following use as well as rapid changes in moles and pigmented lesions that can make detection of skin cancer more difficult, and that case reports cannot establish causation. Recommends discussing changing moles or pigmentation with a board-certified dermatologist. [^12]: Therapeutic Goods Administration (Australia). Don't risk using tanning products containing melanotan. Regulator, read at source. States that supplying tanning products containing melanotan without a prescription is illegal in Australia regardless of form, that advertising it to the public is illegal including promotion by social media influencers, that reported effects of melanotan II include increased moles and freckles, kidney dysfunction and swelling of the brain, that anyone who has recently used it should stop and speak to a health professional, and that no tan, fake or real, protects skin against sun damage.