Copper Peptide (GHK Cu): Clinical Uses, Stability & Compounding Tips What is GHK Cu? GHK Cu (glycyl L histidyl L lysine copper complex) is a naturally occurring peptide in human plasma that: Binds copper ions Acts as a biological signalling molecule Plays a role GHK Cu is one of the most talked about peptides in aesthetics right now. But how much of what you have heard about it is actually true?, Copper peptide, known as GHK Cu, has a growing body of peer GHK CU