Sourcing Melanotan 2 for research

Receptor pharmacology groups often keep Melanotan 2 on the shelf as a reference agonist, for instance to confirm that a new cell line expressing MC4R responds as expected. It normally arrives as a freeze-dried acetate salt in sealed vials. Because it differs from bremelanotide at just one end of the molecule, careful identity testing is part of good practice.

Before ordering, confirm:

• Exact identity: the certificate should give the full sequence with the C-terminal amide (-NH₂). The free-acid form is bremelanotide, a separate compound about one mass unit heavier.
• Mass spectrometry: an observed mass matching roughly 1,024 Da for the batch actually supplied.
• Purity: a batch-specific HPLC trace with the method stated, rather than one general figure for the product line.
• Net peptide content and counter-ion: how much of the powder is peptide, and whether it is an acetate or a trifluoroacetate salt.
• Matching paperwork: the same batch number on the certificate and the vial label, plus a safety data sheet.
• Storage and labelling: shipped and stored cold, dry and away from light, and labelled for laboratory research only.

Whether the material comes from the Peptides EU shop or from elsewhere, the batch number on the paperwork should match the vial.

Some labs also compare each new lot with the previous one in their own receptor assay before using it in a long experiment.