Melanotan I

Educational overview

Melanotan I is listed in the ezGLP knowledgebase under Pigmentation. Evidence and regulatory status can vary by formulation, route, and jurisdiction.

Melanotan I is the original research name for afamelanotide, a synthetic thirteen-amino-acid analogue of alpha-melanocyte-stimulating hormone in which two substitutions, norleucine at position four and D-phenylalanine at position seven, give it greater potency and resistance to degradation than the natural hormone. It was developed at the University of Arizona in the 1980s and is classed as a melanocortin-1 receptor agonist. Activation of MC1R on melanocytes increases production of eumelanin, the photoprotective brown-black pigment, without requiring ultraviolet exposure. Unlike its cyclic relative Melanotan II, afamelanotide is relatively selective for MC1R and lacks the pronounced MC4R-mediated sexual and appetite effects.

Afamelanotide has a substantial and independently reviewed clinical record because it was taken through formal drug development by Clinuvel. The FDA approval package describes three randomised, vehicle-controlled trials in adults with erythropoietic protoporphyria, enrolling 244 subjects, in which the implant increased pain-free time in direct sunlight and delayed phototoxic symptoms. Common adverse reactions were headache and implant-site reactions, and the label notes darkening of pre-existing moles and freckles. A 1997 pharmacokinetic study of the free peptide after subcutaneous injection reported a terminal half-life of roughly one to two hours, which is why the commercial product is a controlled-release implant rather than a solution.

Afamelanotide is approved as Scenesse, a subcutaneous implant, by the EMA since 2014, the FDA since October 2019, and the TGA since 2020, in each case for adult patients with erythropoietic protoporphyria to increase pain-free light exposure. The FDA approval was granted with orphan designation and requires administering clinicians to complete manufacturer training. No injectable solution of afamelanotide is approved anywhere, and no regulator has approved it for cosmetic tanning. Products sold online under the name Melanotan I as lyophilised powder for reconstitution and injection are unlicensed, and regulators including the TGA and the MHRA have warned against tanning peptides generally. Their identity and purity are unverified.

The approved product is dispensed and implanted in a clinic, and the Scenesse label specifies refrigerated storage between two and eight degrees Celsius, protection from light, and insertion by a trained professional using the supplied cannula, so patient-side storage does not arise. Unlicensed Melanotan I powder has no regulator-reviewed storage guidance and relies on supplier statements; peptides degrade with heat, light, and repeated freeze-thaw cycles, and reconstituted solutions have no established beyond-use time. For the licensed product, the record of interest is the implant date and lot number. For unlicensed powder, a dose log recording vendor, lot, reconstitution date, route, and storage, alongside an inventory record, supplies the missing traceability.

Category

Pigmentation

Routes represented

Subcutaneous (SubQ)

Approximate library half-life

1.25 hours; formulation-dependent and not dosing guidance

Storage context

Storage and PK are formulation-dependent; follow the product label. Scenesse implants are refrigerated at 2–8°C and protected from light.