Melanotan 1 vs melanotan 2: afamelanotide, MT2 and the evidence

The two share a purpose and an origin. Both were made by chemists at the University of Arizona to mimic alpha-MSH, the hormone that switches on melanin production, with the aim of a tan that did not depend on ultraviolet light ^[2]. The difference is what happened next. Melanotan 1 was developed by a pharmaceutical company, renamed afamelanotide, tested in randomised trials and licensed as Scenesse for erythropoietic protoporphyria (EPP), a rare inherited condition in which light on the skin causes severe pain ^[8][9]. Melanotan 2 was tested in a handful of volunteers in the 1990s, set aside, and survives mainly as an illegal tanning product ^[2][3].

So the most useful answer to “MT1 vs MT2” is that one is a licensed prescription implant used by specialists for a rare disease, and the other has never been authorised anywhere. Neither is licensed for cosmetic tanning. Products sold online as “melanotan 1” or “melanotan 2” are not Scenesse, whatever the label says. Our melanotan II guide covers MT2 in full.

Melanotan 1 is the full 13-amino-acid alpha-MSH chain with two substitutions: norleucine at position 4 and D-phenylalanine at position 7, which make it longer lasting than the natural hormone ^[4]. The US Scenesse label gives its sequence as Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2 and describes it as a melanocortin 1 receptor (MC1R) agonist ^[10]. MC1R is the receptor on pigment cells that drives production of eumelanin, the darker brown-black pigment.

Melanotan 2 is a shorter, ring-shaped (cyclic) fragment of the same hormone, designed in 1989 to be even more potent and longer acting ^[1]. It is less selective. As well as MC1R it activates MC3 and MC4 receptors in the brain and spinal cord, which is why it also affects sexual function and appetite ^[2]. That lack of selectivity explains most of the practical differences between the two, including the side effects, and it is why the sexual-health drug bremelanotide (PT-141) was developed from melanotan 2 rather than melanotan 1 ^[2].

Melanotan 1 has the larger body of evidence. In healthy volunteers, ten daily injections over two weeks darkened the skin of the face, neck and forearms, with a 98% rise in forearm eumelanin one week after dosing ended ^[5]. In an Australian trial of 65 fair-skinned volunteers, three 10-day courses over three months increased melanin density in every treated person and, in those who burn easily, more than halved the sunburn cells produced by a fixed dose of UV light ^[7]. As afamelanotide, it then went through two randomised, placebo-controlled trials in EPP: in the US trial, patients on the implant spent a median of 69.4 hours in direct sunlight without pain over six months, against 40.8 hours on placebo ^[8].

Melanotan 2 was studied in three small projects by the Arizona group. A 1996 pilot in three men produced measurable tanning in two of them within two weeks ^[3]. Two crossover studies in men with erectile dysfunction found it triggered erections, the second after 12 of 19 injections compared with 1 of 21 placebo doses ^[11][12]. There were no larger trials, and development moved to bremelanotide ^[2].

Before-and-after results in the melanotan 1 studies were measured with instruments, not photographs. In a 1997 study in three men, tanning of the forehead, arms and neck peaked about one week after a 10-dose course and was still present three weeks after the last dose ^[4]. In a later trial, volunteers who took melanotan 1 while getting sunlight on half the back tanned more than those given sunlight alone and kept the tan at least three weeks longer; the sunlight-only group needed 50% more sun exposure for an equal tan ^[6]. The Australian trial reported that the largest increases in melanin were in people who started with the least ^[7].

The US Scenesse label warns that the implant may cause generalised darkening of the skin and darkening of existing moles and freckles, and recommends a full-body skin check twice a year ^[10]. In a study of 15 EPP patients given two implants, dermoscopy showed changes in existing moles at five months that had returned to baseline by twelve months, with no new moles and no features suggesting malignancy ^[17].

Searches for melanotan 2 before and after photos lead mostly to social media. The only controlled melanotan 2 data are the 1996 pilot, in which two of three men showed darkening of the face, upper body and buttocks confirmed by reflectance measurements a week after dosing ^[3]. Photos online cannot show what was in the vial, how much was used, or how much sunbed or sun exposure was involved; the dermatology case reports described below often involve both.

These are doses researchers used or that appear on a licensed label, as information only. In the melanotan 1 tanning studies, injections under the skin ranged from 0.08 to 0.21 mg/kg a day, with 0.16 mg/kg a day for 10 days the most common regimen ^[4][5][6][7]. The licensed product is different: one 16 mg afamelanotide implant inserted under the skin by a trained professional every two months ^[10]. The EU summary says three implants a year are recommended and four is the maximum ^[9].

For melanotan 2, the 1996 pilot started at 0.01 mg/kg and increased in steps to 0.025 to 0.03 mg/kg, and the authors proposed 0.025 mg/kg as the dose for future studies; both erectile dysfunction studies used 0.025 mg/kg ^[3][11][12]. No dose of melanotan 2 has been shown to be safe for repeated cosmetic use. For converting a vial’s milligrams into a volume, our peptide calculator does the arithmetic; the figures here are not recommendations.

In the 1997 study that compared routes, melanotan 1 injected under the skin was completely bioavailable compared with an intravenous dose, while no drug was detectable in the blood after it was taken by mouth ^[4]. We found no published study of a melanotan 1 nasal spray. The licensed form avoids daily injections altogether: Scenesse is a dissolving rod about 1.7 cm long that releases the drug slowly ^[10].

Melanotan 2 is sold as powder for injection, as pre-filled pens and as nasal sprays. The MHRA says products containing melanotan II are classed as medicines if they are injectable or pens, and that a nasal spray is treated as a medicine only if it is sold with claims to treat or prevent disease ^[18]. That is a question of classification, not safety: the MHRA’s advice covers injections and nasal sprays alike.

In the melanotan 1 tanning studies, side effects were described as minimal or minor: occasional stomach upset, nausea and brief facial flushing ^[4][6]. In the pooled Scenesse trials, reactions reported more often than with a dummy implant included implant-site reactions (21% against 10%), nausea (19% against 14%), moles (4% against 2%) and skin darkening (4% against none) ^[10]. The EU overview names nausea, headache and implant-site reactions as the most common side effects ^[9]. The label adds that serious allergic reactions, including anaphylaxis, have been reported since approval ^[10]. The EU summary says Scenesse must not be used by people with reduced liver or kidney function ^[9].

Melanotan 2’s side effects reflect its wider receptor activity. The pilot and erectile dysfunction studies reported nausea, a stretching and yawning reaction, reduced appetite, sleepiness and fatigue, and spontaneous erections lasting one to five hours ^[3][11]. Outside trials, dermatologists have reported new and darkening moles after melanotan injections ^[14], a 2017 review found four published cases of melanoma arising in existing moles during or soon after melanotan use while noting that a causal link is not proven ^[13], and single case reports describe melanoma ^[15], priapism needing surgery ^[16] and a kidney infarction ^[19]. Case reports cannot show how often these happen, and many of the people involved also used sunbeds.

In the UK, the MHRA told a 2024 Freedom of Information requester that unauthorised melanotan products have unknown contents with no safeguards for quality, safety or effectiveness, that anyone who has used melanotan II injections or nasal sprays should stop immediately and report side effects through the Yellow Card scheme, and that selling, supplying or advertising unauthorised medicines is not permitted. It said it had received 16 UK suspected adverse reaction reports for melanotan II between 2012 and 2022, and that it has repeatedly acted to remove melanotan products from the market for over 10 years ^[18]. Public Health England reported in 2013 that men who inject anabolic steroids and tanning drugs are at higher risk of HIV and viral hepatitis, with 1 in 10 of 395 men surveyed exposed to at least one of these infections ^[24]. See UK legal status.

Other regulators say the same. Australia’s TGA says melanotan II is a prescription-only substance, that no product containing it is approved there, and that supplying tanning products containing it without a prescription is illegal ^[20]; it sits in Schedule 4 of the June 2026 Poisons Standard ^[27]. See Australian legal status. In April 2026 Health Canada named “Melanotan I and II” among examples of unauthorised injectable peptide drugs it had seized, and said research-use-only labelling does not make them legal ^[21]; see Canadian legal status. In May 2026 New Zealand’s Medsafe listed melanotan II among peptide products advertised online and said it is illegal to import, sell or use these products ^[22]; its classification database lists melanocyte-stimulating compounds and afamelanotide as prescription medicines ^[26].

In the US, the FDA has treated melanotan II as an unapproved new drug in enforcement proceedings against a seller ^[23], and its compounding page (as of April 2026) records melanotan II among substances whose nominations for pharmacy compounding were withdrawn, which does not authorise it ^[25]. See US legal status.

Yes, in one specific form. The FDA approved Scenesse (afamelanotide) implant, 16 mg, on 8 October 2019 under application NDA 210797 ^[28]. The label limits it to increasing pain-free light exposure in adults with a history of phototoxic reactions from EPP, and says it should be given by a healthcare professional ^[10]. The European Medicines Agency authorised Scenesse on 22 December 2014 under exceptional circumstances, because the rarity of EPP meant complete information on its benefits could not be obtained ^[9].

That approval does not extend to tanning, to injections of melanotan 1 powder, or to any product sold by research peptide vendors. Those are unlicensed products whose content has not been checked by a regulator.

We track suppliers for melanotan 2 only: see melanotan II prices and melanotan II suppliers in the UK. Listing a product does not make it legal where you live, and no licensed melanotan 2 product exists anywhere. If you are assessing a supplier, our guides on how to read a peptide COA and how to spot a fake peptide supplier explain what evidence to look for, and our list of third-party tested suppliers shows which publish independent results.