Melanotan 1: the tanning peptide that became a licensed medicine, and the powder that did not

Melanotan 1 (melanotan I, MT-1) is a synthetic version of alpha-melanocyte-stimulating hormone (alpha-MSH), the 13-amino-acid hormone that tells pigment cells in the skin to make melanin. Chemists at the University of Arizona made it in 1980 by changing two of the hormone’s amino acids: methionine at position 4 was replaced with norleucine, and the L-phenylalanine at position 7 with its mirror-image D-form. The result, [Nle4-D-Phe7]-alpha-MSH, resisted breakdown by enzymes and was far more potent and longer acting than the natural hormone in frog-skin and lizard-skin assays ^[1].

Over the following decade the same group tested the peptide as a tanning agent in people and gave it the working name melanotan I ^[3][20]. A cyclic, shorter analogue from the same programme became melanotan II, which acts on more receptors and was never approved. Melanotan I was licensed to the Australian company Clinuvel and developed under the international name afamelanotide; it was approved in the EU in 2014 and in the US in 2019 as Scenesse, an implant for a rare inherited light-sensitivity disease ^[14][16].

So the melanotan 1 peptide has two lives. One is a prescription-only implant with a full clinical trial record. The other is a freeze-dried powder sold by research peptide suppliers and tanning sellers, usually labelled MT-1 or MT1, which is chemically the same molecule but is not made, tested or supplied under any licence. This guide covers both, and is careful to say which evidence belongs to which.

Alpha-MSH and afamelanotide both bind the melanocortin 1 receptor (MC1R) on melanocytes, the pigment cells of the skin. Activation of MC1R switches melanin production towards eumelanin, the brown-black pigment, and increases the amount made. Because the analogue is resistant to enzymes and binds tightly, the effect of a course of injections lasts well after the drug has gone: in the 1991 trial, skin darkening peaked one to three weeks after the last injection ^[2], and in a 1997 pharmacokinetic study, tanning of the forehead, arms and neck peaked a week after dosing and was still present three weeks later ^[3].

A 2000 study in human volunteers confirmed that the pigment being made is eumelanin. Ten daily injections increased eumelanin in skin biopsies and increased tanning measured by reflectance, with the largest effects in people whose skin was lightest at baseline ^[4]. Eumelanin is the pigment associated with better protection from ultraviolet damage, which is why the compound was later tried as a photoprotective drug rather than a cosmetic one.

Unlike melanotan II, melanotan I is a linear peptide with a strong preference for MC1R over the MC3 and MC4 receptors in the brain that control appetite and sexual function. That selectivity is the main reason the two compounds differ in their side effects, as set out on our melanotan 1 vs melanotan 2 page.

The claimed melanotan 1 benefits are a tan with less sun, protection from sunburn, and relief in medical conditions where light damages the skin. Each rests on a different body of evidence.

Tanning: in a 1991 randomised, placebo-controlled trial at the University of Arizona, 28 healthy white men received ten subcutaneous injections of the peptide or saline over 12 days while using a high-potency sunscreen. Skin darkened measurably in both poor tanners (skin types I and II) and good tanners (types III and IV) given the peptide, and in nobody given placebo ^[2]. Later studies showed the tan came with more eumelanin in the skin ^[4] and that combining the peptide with a small amount of solar UV produced a deeper, more even tan than either alone ^[5].

Sunburn protection: a 2006 Sydney study gave 65 volunteers 0.16 mg/kg by subcutaneous injection for three 10-day cycles over three months. Melanin density rose in every treated subject, by an average of 41% in people with the most sun-sensitive skin. After a controlled UV exposure, sunburn cells in the epidermis fell by more than half in those fair-skinned volunteers and thymine dimers, a marker of DNA damage, fell by 59% ^[6]. This is the strongest evidence that induced pigmentation protects skin, but it is short-term laboratory data, not a trial showing fewer skin cancers.

Light-sensitivity disease: the medical use that led to approval is erythropoietic protoporphyria (EPP), in which a build-up of protoporphyrin makes sunlight cause severe pain within minutes. A 2009 letter in the New England Journal of Medicine first reported that afamelanotide implants let EPP patients tolerate more light ^[7]. Two phase 3 trials followed and are described below ^[8].

Vitiligo: in a 2015 randomised trial in 55 patients with darker skin types, adding monthly 16 mg afamelanotide implants to narrowband UV-B phototherapy produced faster and greater repigmentation than phototherapy alone, with 48.6% repigmentation at day 168 versus 33.3%. The benefit was clearest in skin phototypes IV to VI ^[10]. It is not an approved use.

The pivotal evidence comes from two multicentre, randomised, double-blind, placebo-controlled trials published together in 2015. In the EU study, 74 EPP patients received a 16 mg afamelanotide or placebo implant under the skin every 60 days for five implants; in the US study, 94 patients received three. The primary outcome was hours of direct sunlight exposure without pain. In the US trial the median pain-free time over six months was 69.4 hours with afamelanotide against 40.8 hours with placebo; in the EU trial it was 6.0 hours against 0.8 hours over nine months, and the number of phototoxic reactions fell from 146 to 77. Quality of life improved in both trials, and serious adverse events were not thought to be related to the drug ^[8].

Long-term data come from an observational study of 115 EPP patients treated with 1,023 implants over up to eight years at porphyria centres in Rome and Zurich. Quality-of-life scores rose from 31% of maximum before treatment to 74% after starting and stayed there; 23% of patients stopped, mostly for reasons such as pregnancy or cost, and only minor adverse events, mainly nausea, were attributed to the drug ^[9].

The tanning studies of the 1990s and 2000s were small: three men in the pharmacokinetic study ^[3], 28 in the 1991 trial ^[2], and 65 in the 2006 photoprotection study ^[6]. No phase 3 trial of melanotan 1 for cosmetic tanning was ever run, and no study has tested whether it prevents skin cancer.

In the controlled studies, darkening was detectable during a 10-dose course and peaked one to three weeks after the last injection ^[2][3]. The tan was still measurable three weeks after a course ended ^[3], and the three-cycle Sydney protocol kept melanin raised over three months ^[6]. For the implant, pain-free light tolerance in EPP was measured over six to nine months of two-monthly implants ^[8]. These timelines come from supervised dosing of pharmaceutical-grade material; they do not describe what happens with an unlicensed powder of unknown content.

Every published human study used subcutaneous injection or the implant, and every dose was calculated by body weight or fixed by the licensed product. The 1997 pharmacokinetic study gave 0.16 mg/kg intravenously and orally and 0.08 to 0.21 mg/kg subcutaneously, ten doses over two weeks. Subcutaneous doses were fully absorbed, oral dosing produced no detectable drug in blood, and the elimination half-life after injection was 0.8 to 1.7 hours ^[3]. The 2006 photoprotection trial used 0.16 mg/kg daily for three 10-day cycles ^[6]. The licensed implant contains 16 mg and is inserted by a trained professional every two months ^[8][15].

These figures describe what studies used; they are not recommendations. A melanotan 1 dosage chart of the kind circulated on forums does not come from any trial, and the online products it refers to have not been shown to contain a consistent amount of peptide. Our peptide calculator does the arithmetic for reconstituting a vial, but it cannot tell you what the vial holds.

The licensed form is a single 16 mg dissolving implant, about the size of a grain of rice, placed under the skin above the hip; it releases the drug over days and the label reports a half-life of about 15 hours from the implant ^[15]. Research and tanning sellers instead offer freeze-dried powder in vials for injection, sometimes pre-mixed pens, and nasal sprays.

We found no published human study of a melanotan 1 nasal spray, so nothing is known about how much of it is absorbed. Oral dosing at 0.16 mg/kg produced no measurable drug in blood in the 1997 study ^[3], which is why capsules and drops are unlikely to work. Injecting any unlicensed product also carries the risks of non-sterile preparation and shared equipment.

In the tanning studies, side effects were minimal and consisted of occasional stomach upset and facial flushing ^[3]. In the EPP trials and the long-term study the most common effects were nausea, headache and implant-site reactions, and serious adverse events were not attributed to the drug ^[8][9]. The US label lists implant-site reactions, nausea, oropharyngeal pain, cough, fatigue, dizziness and darkening of the skin and of moles among its warnings ^[15].

Moles are the main safety question. A 2021 Italian study followed the moles of EPP patients treated with afamelanotide and found clinical and dermoscopic changes, including darkening, which the authors recommended monitoring with full skin examinations ^[11]. The label advises the same ^[15]. The concern with unlicensed use is that new or changing moles go unexamined. A 2017 review found that case reports of melanocytic changes, new dysplastic naevi and four melanomas arising in existing moles involve both melanotan I and melanotan II, while noting that conclusive evidence of cause and effect is lacking ^[12].

Unlicensed products add risks that have nothing to do with the molecule. A 2009 BMJ report on the use of melanotan I and II in the general population highlighted that users were injecting products of unknown content and sterility, obtained from websites and gyms, without medical oversight ^[13]. Regulators make the same point ^[17][18]. Nothing in the afamelanotide trial record can be read across to a powder from an unregulated source.

Searches for melanotan 1 for bodybuilding or weight loss have no evidence behind them: we found no study of melanotan 1 and muscle, strength or body composition. Reduced appetite was reported with melanotan II, which acts on the MC4 receptor, not with melanotan I.

Both compounds copy alpha-MSH and both came from the University of Arizona. Melanotan 1 is linear, 13 amino acids long and selective for the MC1 receptor; melanotan 2 is a cyclic seven-amino-acid fragment that also activates the MC3 and MC4 receptors, which is why its pilot studies recorded nausea, yawning, reduced appetite and spontaneous erections alongside tanning. Melanotan 1 became a medicine with two phase 3 trials and a long-term safety record in EPP ^[8][9]; melanotan 2 never got past small pilot studies. Neither is approved for cosmetic tanning, and the melanotan 1 sold online is not the licensed implant. Our melanotan 1 vs melanotan 2 comparison sets the two out side by side, and the melanotan II guide covers that compound in full. PT-141 (bremelanotide), a derivative of melanotan 2, is the third member of the family with an approved medicine.

Afamelanotide is a prescription-only medicine. The European Commission authorised Scenesse in December 2014, under exceptional circumstances because the rarity of EPP limited the evidence available, and the EMA’s product information restricts use to adults with EPP and to administration by a physician trained by the company ^[14]. The FDA approved it in October 2019 under NDA 210797 to increase pain-free light exposure in adults with a history of phototoxic reactions from EPP ^[16][15]. It is not approved anywhere for tanning, vitiligo or any cosmetic use.

The material sold as melanotan 1 or MT-1 powder has no marketing authorisation in any country. In the UK, the MHRA treats injectable melanotan products as unlicensed medicines that may not be sold, and its disclosures of Yellow Card reports cover melanotan tanning products generally ^[17]. Health Canada’s April 2026 advisory on unauthorised injectable peptides names melanotan I among the products it has seized ^[18]. See our legal status overview and the UK, US, Canadian and Australian pages for the rules on buying and holding research peptides.

We have not confirmed whether melanotan I appears by name on the WADA Prohibited List; unlike AICAR or myostatin inhibitors, it is not a performance-enhancing agent in the usual sense.

The licensed implant is stored refrigerated in its sealed vial until use, per the product information ^[15]. Unlicensed melanotan 1 is supplied as a freeze-dried powder that, like other peptides, is kept cold, dry and away from light and is less stable once mixed. See how to store peptides and our guide to bacteriostatic water.

Because the licensed product is only available through porphyria specialists, every vial of melanotan 1 for tanning or research sold online is unlicensed and its content cannot be assumed. If you are researching suppliers, you can compare melanotan 1 prices, read how to read a COA, see our third-party tested suppliers and learn how to spot a fake peptide supplier.

We track listings in the UK and the US. A certificate of analysis should report a measured mass close to 1646.8 g/mol ^[19]; a different mass suggests a different or incomplete peptide, and a store that cannot show one is worth avoiding. Our guide to third-party peptide testing explains what a credible test looks like.