Not all copper peptide serums are formulated the same Before you buy one, make sure you're actually getting pure GHK Cu at the right concentration not just a diluted blend. We spent GHK Copper Peptide Concentrate, cumpr ingredient cosmetic GHK CU Copper Peptide Face Serum Robyn's Tack Room ROBYN'S TACK ROOM GHK CU Copper Peptide, Face Serum, 1 oz (30 ml) Copper Peptide Serum (GHK Cu) Nardo's Natural Private Label