What a Copper Peptide Is Called on a Cosmetic Label

By What Peptides Editorial Team · Updated 2026-09-14 · Part of Cosmetic Peptide Benefits, Uses & Skincare Products Guide

A copper peptide is a short chain of amino acids bound to a copper ion, and the same molecule can carry four or five different names depending on who is writing. A chemist writes a three-letter sequence, a research catalog writes a shorthand such as GHK-Cu, a cosmetic label writes a standardized INCI name, and a marketing team writes something else again. This page maps one naming system onto the next so that a label can be read against the literature without guessing. No claim is made about what any of these ingredients does.

The naming matters because searchers often meet the research shorthand first and then fail to find it on a product. The cosmetic peptide benefits and uses hub uses label vocabulary, while how peptides are named in other contexts covers the wider problem of peptide synonyms. The short version is that the word copper on a cosmetic label is part of a standardized name, and the shorthand used in catalogs is not the form that appears on the pack.

From Three Amino Acids to a Label Name

The best known copper-binding tripeptide is built from glycine, histidine and lysine in that order. Written in the three-letter residue notation used in biochemistry it reads Gly-His-Lys, and in one-letter notation it reads GHK. Using the average residue mass of about 110 Da, with glycine at 57.02, histidine at 137.06 and lysine at 128.09 as monoisotopic residue values, the free tripeptide works out at roughly 340 Da. Complexing a copper ion adds on the order of 60 Da more, so the metallated form sits near 400 Da. These are ordinary small-molecule dimensions, far smaller than a protein.

The binding is the interesting part of the chemistry. Histidine provides an imidazole side chain that coordinates metal ions, and the N-terminal amine and adjacent deprotonated amide nitrogens complete the coordination environment for copper. That is why the sequence, not merely the composition, determines whether a given tripeptide carries copper at all. A scrambled version with the same three residues will not behave the same way, which is one reason the sequence notation is more informative than a list of component amino acids. Each of the naming systems above answers a different question, and only one of them is the form a regulator expects to see printed on a pack.

INCI Names and Why the Number Is Not Chemistry

INCI names are assigned through a registration process and published in databases such as the European Commission's CosIng, which is free to search. The number appended to a peptide name is a sequential registration marker, not a description of chain length or potency. Tripeptide-1 and tripeptide-29 are therefore not comparable on the basis of their numbers, and a high number does not imply a newer or stronger material. The convention exists so that the same substance is declared under the same name on every pack in a market, which is what makes cross-brand comparison of panels possible at all. It is an identification system, not a grading system.

Two further conventions cause confusion. Metal-bearing names declare the metal as part of the ingredient name, so copper tripeptide-1 and tripeptide-1 are distinct declarations rather than two ways of writing one thing. Lipid-modified peptides carry a prefix such as palmitoyl, acetyl or myristoyl, indicating that a fatty acid group has been attached to improve compatibility with an oil phase. None of these names states how much of the ingredient is present, and none of them is a statement about outcome. They are identification strings, and that is all they are, which is why two products declaring the same name are not automatically comparable in any other respect.

How to Check Which Name Your Product Actually Uses

Start from the ingredient panel rather than the front of the pack. The front may use the research shorthand or a trade name, but the panel must use the standardized INCI form in most markets. Copy the name exactly, including hyphens and numbers, then search it in CosIng to confirm that it is a recognized cosmetic ingredient and to see any functions recorded against it. If the panel shows only a generic tripeptide name without the metal, then the declared ingredient is the unmetallated peptide, whatever the front of the pack says.

A second check is worth doing when the product name and the panel disagree. Look up the free peptide in a chemical database such as PubChem to confirm the sequence and the mass, and check whether the supplier or brand publishes a specification sheet naming both forms. Discrepancies between marketing copy and the panel are common and are not necessarily deceptive, because a brand may describe a complex by its research name while declaring it under its INCI name. For related label reading, see reading a named skincare term and ingredient panels on a peptide cream.

This page is part of the Cosmetic Peptide Benefits, Uses & Skincare Products Guide guide.