Melanotan I

Melanotan I is the one peptide on this list that became a licensed medicine. Under the name afamelanotide, marketed as Scenesse by Clinuvel, it was approved by the European Commission in 2014 and by the US Food and Drug Administration in October 2019 to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria [5]. That distinction matters throughout what follows, because the same molecule exists in two entirely different worlds: a regulated 16 mg implant inserted by a trained clinician, and a vial of powder bought online for tanning.

Chemically, afamelanotide is [Nle4-D-Phe7]-alpha-MSH, a 13-residue analogue of the natural melanocyte stimulating hormone with two substitutions that dramatically increase potency and resistance to degradation. It acts mainly at the melanocortin 1 receptor on melanocytes, stimulating production of eumelanin, the darker and more photoprotective form of melanin. It is a linear peptide and reasonably selective for MC1R, which distinguishes it from Melanotan II, a cyclic analogue that hits MC3R and MC4R as well and produces the sexual and nausea effects that made that compound notorious.

Erythropoietic protoporphyria is a rare inherited disorder in which protoporphyrin accumulates and reacts with light, producing severe burning pain in the skin after even short sun exposure. Patients often live largely indoors. The clinical case for afamelanotide was that increasing constitutive melanin would raise the threshold for phototoxic reactions and give patients usable daylight hours. The pivotal evidence appeared in the New England Journal of Medicine in 2015, reporting randomised trial results in EPP patients [1]. A long-term observational study of 115 patients published the same year in the British Journal of Dermatology provided the durability and safety data that regulators needed [2], and a 2016 review in the American Journal of Clinical Dermatology summarised the package [3].

The approved regimen is a single 16 mg implant placed subcutaneously above the anterior supra-iliac crest every two months during the sunlight season, administered by a healthcare professional trained in the implantation procedure. The label's most common adverse reactions are implant-site reaction, nausea, oropharyngeal pain, cough, fatigue, dizziness, skin hyperpigmentation, somnolence, melanocytic naevus, respiratory tract infection and skin irritation. Two label points deserve emphasis. First, twice-yearly full-body skin examination is recommended, because a drug that darkens skin and increases naevi can mask or mimic changes that matter. Second, patients are told to maintain sun protection: afamelanotide raises the phototoxicity threshold, it does not make skin safe.

Outside EPP, the evidence thins quickly. A 2015 randomised multicentre trial in JAMA Dermatology tested afamelanotide combined with narrowband UV-B for vitiligo and reported greater repigmentation than phototherapy alone [4], but this has not translated into an approval. A 2023 open-label phase IIa study in BMC Neurology explored feasibility and safety in acute stroke, which is exploratory work with no efficacy conclusion attached.

The grey market is a different proposition entirely. Melanotan I sold as a lyophilised powder for self-injection has no approval, no quality oversight, no dose standardisation and no dermatological monitoring. National medicines agencies in the UK, Australia, Norway and elsewhere have issued repeated warnings about unlicensed melanotan products, and the melanotan case-report literature, mostly concerning Melanotan II, includes darkening and change of existing naevi, eruptive naevi and reports of melanoma diagnosed in users. Causation in individual case reports is not established, but the mechanism gives a plausible reason for concern: stimulating melanocyte activity in people who are also seeking sun exposure is not a neutral combination, and doing so without the twice-yearly skin checks the approved product requires removes the safeguard that exists precisely for this risk.

There is also no longevity rationale here. Afamelanotide is a photoprotective drug for a specific metabolic disease. Extending that into an anti-ageing or skin-health claim has no evidential basis, and the cosmetic tanning use inverts the logic by encouraging more sun exposure rather than less.

Our position: as afamelanotide, this is a legitimate, well-evidenced orphan drug and the highest-rated compound in this section at tier 2. As grey-market Melanotan I injected for cosmetic tanning, it is an unapproved use of a potent melanocyte stimulant without the surveillance that its own label requires. Those two things share a molecule and nothing else.