As of July 26, 2026, 21 CFR 216.23 lists six substances that can be used through this pathway: Brilliant Blue G, cantharidin for topical use only, diphenylcyclopropenone for topical use only, N-acetyl-D-glucosamine for topical use only, squaric acid dibutyl ester for topical use only, and thymol iodide for topical use only
GHK-Cu Copper Peptide Names and Forms GHK-Cu copper peptide terminology can be confusing because the same topic appears under several names, including GHK, copper peptide, copper peptide GHK-Cu, GHK copper, copper tripeptide, Cu-GHK, and prezatide copper [1], [9]
Guglielmi, G
For newcomers to this drug class, our primer on what a GLP-1 is and how these peptides are described in research gives the vocabulary used throughout