The Copper Peptide Revolution and the Rise of GHK-Cu in Modern Research GHK-Cu, or glycyl-L-histidyl-L-lysine copper, is far more than just another peptide on the laboratory shelf. Naturally present in human plasma, saliva and urine, this tripeptide possesses an exceptionally high affinity for copper ions, forming a complex that has fascinated cell biologists, dermatology researchers…