MT-1 / Melanotan-I

Developed in 1980s University of Arizona work on α-MSH analogs as sunless tanning agents. It is native α-MSH with two amino-acid swaps (norleucine at 4, D-phenylalanine at 7) that resist breakdown and prolong receptor binding.

Activates the MC1R receptor on pigment cells, raising brown-black eumelanin without UV exposure. In erythropoietic protoporphyria (EPP), the extra melanin is thought to block visible light before it reaches light-reactive protoporphyrin in the skin. It is more MC1R-focused than MT-2, consistent with its lack of erection and appetite effects.

Two randomized phase 3 trials of the implant in EPP (NEJM 2015) reported more pain-free time in direct sunlight and fewer phototoxic reactions than placebo, and real-world cohorts in the Netherlands and Germany report high long-term continuation. In vitiligo, a 55-patient trial combining the implant with narrowband UVB phototherapy reported more repigmentation than phototherapy alone, confined to darker skin types; a phase 3 vitiligo trial was ongoing in 2026. It has also been studied in other light-sensitivity disorders. Long-term melanoma risk and the behavior of non-implant forms remain open questions.

On the US label, implant-site reactions, nausea, throat pain, cough, fatigue, skin darkening and new moles were more common than with an inactive implant; headache is also common. It darkens skin, moles and freckles, so the label recommends full-body skin exams twice a year; anaphylaxis is uncommon but reported. Unlicensed 'melanotan' products have been linked to new and changing moles.

The brand drug Scenesse (an implant) was FDA-approved in October 2019 for adults with EPP, and approved in the EU in 2014; approval does not cover research powder, and vitiligo is not an approved use. Afamelanotide is not on FDA's Category 2 list. It is not named on the 2026 WADA list and, as an approved substance, falls outside S0.