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Compound guide
Melanotan I: what the research covers
A close copy of alpha-MSH with two substitutions, and — unlike its better-known successor — selective for the receptor that controls pigmentation.
What Melanotan I is
Alpha-melanocyte-stimulating hormone is thirteen residues long and is cleared within minutes. Melanotan I is the same sequence with two changes: norleucine replacing methionine at position four, and D-phenylalanine replacing the L form at position seven. Both substitutions block degradation, and the D residue also locks a conformation the receptor prefers, so potency rises as well as duration.
Critically, the molecule remains linear and it remains selective. It is an agonist at MC1R, the melanocortin receptor on melanocytes that drives eumelanin synthesis, and it does not engage the other melanocortin receptors to any significant degree.
That selectivity is the whole difference from Melanotan II, which is cyclic and non-selective and consequently has an entirely different reported profile. The two are often conflated, and they should not be.
The one compound here with a regulatory approval for its original purpose
Melanotan I is marketed as afamelanotide for erythropoietic protoporphyria, a rare inherited condition in which light exposure causes severe pain. The approval rests on controlled trials, which makes the MC1R mechanism unusually well supported for a compound in this catalogue — the pigmentary pathway is not in doubt.
The research literature covers MC1R signalling through cyclic AMP and the microphthalmia-associated transcription factor, eumelanin versus pheomelanin synthesis, photoprotection measured as minimal erythema dose, and MC1R polymorphism, which is the genetic basis of red hair and fair skin and a determinant of how much response is possible in a given individual or cell line.
For comparative work, the Melanotan I and Melanotan II pairing is a clean selective-versus-non-selective contrast on the same receptor family, set out on Melanotan I versus Melanotan II.
How Amino Club supplies it
Supplied lyophilised in sealed vials as Melanotan I, specified at 99% purity or better by HPLC with identity confirmed by mass spectrometry and released against the batch Certificate of Analysis. The lab testing page sets out the release sequence.
The D-phenylalanine substitution is invisible to mass spectrometry, since the D and L forms have identical mass, so stereochemistry rests on the synthesis route and on chromatographic behaviour against reference material — a point worth understanding when reading any Certificate of Analysis for a peptide containing D residues. The powder is stored below −18 °C and kept dark; solutions are prepared in small volumes and protected from light. Diluents are under reconstitution supplies.
Related reading
Melanotan I belongs to the skin and cosmetic research peptides group with Melanotan II, GHK-Cu, AHK-Cu, SNAP-8 and glutathione. Its melanocortin parentage also links it to KPV, a fragment of the same hormone.
Every guide is indexed in the research library. Certificates and storage are covered on the FAQ, quantity pricing through bulk and wholesale.
Research use only
Melanotan I supplied by Amino Club is a laboratory reference material. It is not a medicine, not a supplement, and not for human or veterinary use, and no dosing guidance or administration protocol is provided. The full terms are in the research use policy.