Formulation chemistry inherited a working classification for topical peptides: signal peptides, carrier peptides, neurotransmitter-type peptides, and enzyme-inhibitor peptides. The grouping is useful for organizing an ingredient list. It is not a substitute for structure, INCI or research name, and a lot file.
Signal peptides
These are short, defined sequences used as discrete raw materials in leave-on systems. Palmitoylated fragments, for example, are still identified by sequence plus modification, not by the word "signal." The professional file needs the sequence or INCI name, the salt form, and a method-stated purity.
Carrier peptides
Carrier peptides are sequences associated with coordinating a metal ion, most often Cu(II). The peptide ligand and the metal complex are not automatically the same SKU. A specification should state whether the material is the free peptide, a defined complex, and at what stoichiometry if a ratio is claimed.
Neurotransmitter-type peptides
This heading appears in many cosmetic ingredient taxonomies. Treat it as a filing label. The receiving lab still identifies a named sequence, a method, and a batch number.
Enzyme-inhibitor peptides
A fourth heading used in the same literature. The purchase record remains the structure and the COA, not the heading.
How to use the taxonomy
Use the four headings only to sort a long catalog. When a quote is issued, drop the heading and keep name, sequence or INCI, format, net content, purity method, identity method, and lot.
Research-use and professional buyer information only. Class names are not performance claims.