Copper Peptide Regenerating Serum for Glowing Skin and Hair The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Defy GHK Cu (glycyl L histidyl L lysine) is a naturally occurring copper binding peptide found in human plasma. As levels decline with age, so may its support of the biological processes involved in collagen production, skin GHK Cu Copper Peptide Benefits, Uses & Safety Intra V