GHK Cu is getting a lot of attention right now, and for good reason. This is not just a skin peptide. It's a copper binding tripeptide with documented effects on gene expression, collagen synthesis, GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? GHK Cu Engage Peptides 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