What Melanotan I is
The MT1 peptide, Melanotan I, is α-melanocyte-stimulating hormone with two deliberate changes: norleucine at position 4 and D-phenylalanine at position 7. The first removes a methionine that oxidizes easily; the second resists enzymatic cleavage and strengthens binding at the melanocortin 1 receptor. The 13-residue chain keeps α-MSH's acetylated N-terminus and amidated C-terminus, giving C78H111N21O19 and 1646.85 g/mol.
MT1 Peptide Co. lists MT1 in 10 mg vials at $29.99 through Klow.bio. Lot KB-34289 tested at 97.55% by HPLC at ILS Laboratories, with Melanotan I identity confirmed against a reference standard.
MT1 is a linear peptide and a different compound from Melanotan II (MT2), which is a shorter, cyclic analog. The two have different formulas and molecular weights (1646.85 vs 1024.18 g/mol).
Structure
MT1 is linear, with an acetylated N-terminus (Ac-Ser1) and amidated C-terminus (Val13-NH2). Position 4 is norleucine (Nle) and position 7 is D-phenylalanine. The central His-D-Phe-Arg-Trp segment is the core shared by melanocortin receptor ligands. The single tryptophan (Trp9) is its most oxidation-sensitive residue.
complete MT1 specifications.
Storage and handling
Store sealed, dry and protected from light at the temperature stated on the vial label. Allow a cold vial to reach room temperature before opening. Lyophilized material absorbs moisture from the air, and absorbed moisture restarts the reactions that drying slows, so keep vials sealed until needed. Storage and stability guide.