NL GHK Cu (TETRAPEPTIDE + CU) Synthagen Synthagen PL Ozark Have you heard of GHK Cu the copper peptide your body is already making? GHK Cu (Glycyl L Histidyl L Lysine Copper) is a naturally occurring tripeptide found in human plasma, saliva, and urine. GHK Cu Peptide: Turn Back the Clock Naturally Calibrate Hydration GHK Cu 50mg Particle Peptides Ghk Cu Shampoo Copper Peptide Hair Growth Best Peptide for Hair Growth Copper Peptide Shampoo GHK Cu Glow Peptide Stack for Skin Rejuvenation Jennifer R. Berman MD