Skin & Aesthetics
Melanotan II
aka MT-II · MT2 · Melanotan 2 · MTII · the 'Barbie drug' · tanning jab · mt-2 · barbie drug · tanning peptide · tanning injection · melanotan ii
Grade
An unlicensed injectable peptide that darkens skin without sun exposure, sold illegally in the UK and linked to nausea, prolonged erections and worrying changes in moles.
- Class
- Synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH); non-selective melanocortin receptor agonist
- Evidence
- Grade C · Early / limited human data
- Last reviewed
- 2026-06
Grade C · Early / limited human data
Why this grade
Melanotan II reliably produces skin tanning in humans and genuine early human data exists (small studies in the 1990s-2000s and an extensive case-report literature), so it clears the bar for D. However, it was never approved, no completed late-phase efficacy and safety programme exists for tanning, and the human dataset is small and old. Most current knowledge comes from adverse-event case reports of unregulated grey-market use rather than controlled trials. This combination of real but early and limited human data, no approval, and a growing harm signal places it at C, not B.
What is it?
Melanotan II is a lab-made copy of a natural body signal that tells your skin to make more brown pigment. People inject it to go darker without the sun. It does work, but it is not a medicine you can legally buy in the UK. Nobody checks what is actually in the vials sold online. It comes with real downsides: feeling sick, your face flushing, moles darkening or new ones appearing. In men, erections can become painfully prolonged. Doctors have reported skin cancers in some people who used it. The idea that it gives you a safer tan is misleading.
It is like buying an unlabelled paint sprayer from a stranger to darken your skin. It really does change the colour. But nobody can tell you what is in the can. The trigger sometimes jams in dangerous ways: priapism and severe nausea. The people who first studied it walked away before finishing the safety work. Meanwhile, doctors keep reporting that some users' moles have turned nasty.
How is it meant to work?
Non-selective agonism at melanocortin receptors. MC1R activation on melanocytes upregulates melanin synthesis (eumelanogenesis) via the cAMP–PKA–MITF pathway, producing UV-independent skin darkening. MC4R agonism in the central nervous system drives appetite suppression and erectile responses. MC3R and MC4R activity contribute to cardiovascular and sympathetic effects. Typically administered by subcutaneous injection; unregulated use also occurs as nasal spray.
What's it studied for?
Research contexts. Not proven uses, and not recommendations.
Does the human evidence stack up?
Real but limited and old. Small human studies in the 1990s and 2000s confirmed that Melanotan II produces measurable skin darkening and explored its erectile effects. The same melanocortin pharmacology produced a licensed cousin, bremelanotide/PT-141, for premenopausal women with acquired generalised hypoactive sexual desire disorder. Melanotan II itself was never taken through completed late-stage efficacy and safety trials and was never approved. Most current knowledge comes from case reports describing harms in people using unregulated product: nausea and vomiting, facial flushing, mole darkening, eruptive and atypical naevi, cutaneous and mucosal melanoma, ischaemic priapism, and acute systemic toxicity including hypertension and rhabdomyolysis. There is no controlled evidence that it is safe for cosmetic use.
What could go wrong?
- !Unlicensed and illegal to sell or supply for human use in the UK; grey-market vials have unknown purity, content and sterility
- !Multiple published case reports of melanoma (cutaneous and mucosal) and eruptive/atypical moles in users; any 'protective tan' claim is not supported
- !Ischaemic priapism in men, which can require emergency intervention and may cause lasting erectile dysfunction
- !Acute systemic toxicity reported: hypertension, tachycardia, severe nausea/vomiting, rhabdomyolysis
- !Non-sterile injecting and shared equipment carry blood-borne infection risk
- !Users tend to self-select for high UV/sunbed exposure, compounding melanocyte stimulation in an already higher-risk group
- !Nasal-spray formulations sold online add mucosal exposure, with at least one reported case of oral mucosal melanoma
Is it legal in the UK?
Not a licensed medicine in the UK. Melanotan II is an unlicensed product and it is illegal to sell or supply it for human use. The MHRA has repeatedly warned the public not to use unlicensed tanning injections or nasal sprays containing melanotan and has acted to shut down supplying websites. It is sold online as a 'research chemical' labelled 'not for human consumption', a tactic to sidestep medicines regulation but one that does not make human use safe or legal. There is no legitimate prescription route for cosmetic tanning.
Sources
- 01Melanotropic peptides: more than just 'Barbie drugs' and 'sun-tan jabs'? — Langan EA, Nie Z, Rhodes LE, British Journal of Dermatology (2010)
UK review of melanotan peptides covering pharmacology, unregulated use and public-health concerns.
- 02Melanotan-associated melanoma — Paurobally D, Jason F, Dezfoulian B, et al., British Journal of Dermatology (2011)
Case report linking Melanotan II use to a changing pigmented lesion and melanoma.
- 03alpha-Melanocyte-stimulating hormone-induced eruptive nevi — Cardones AR, Grichnik JM, Archives of Dermatology (2009)
Reports rapid appearance of new/atypical melanocytic naevi after melanotan injection. Journal and identifier verified by PubMed search; exact DOI not confirmed here.
- 04Melanotan Tanning Injection: A Rare Cause of Priapism — Mallory CW, Lopategui DM, Cordon BH, Sexual Medicine (2021)
Ischaemic priapism following subcutaneous Melanotan II used for tanning, requiring surgical intervention.
- 05Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?, International Journal of Oral and Maxillofacial Surgery (2025)
Oral mucosal melanoma in a young user of melanotan nasal spray; notes only a handful of prior melanoma reports, all previously from injection.
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