The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds, GHK Cu vs AHK Cu: A Scientific Comparison of These Peptides Peptide Tech Copper Tripeptide 1 (GHK Cu) Cosmetic Ingredient Guide In Vitro and in Vivo Studies of pH Sensitive GHK Cu Incorporated Polyaspartic and Polyacrylic Acid Superabsorbent Polymer ACS Omega