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 Amazon.com: Skin Perfection Copper Peptide Serum GHK CU 1% for Face & Hair Copper Peptides for Skin, Hair, & Scalp 1% Blue Liquid for Face, Neck, Body, Scalp Multi Use Serum Booster with Neurogan Health, Copper Peptide GHK CU, 120 mcg, 60 Tablets iHerb Skin Perfection Ghk Cu Copper Peptide Powder 99.7% Pure Diy Ghk Powder to Make a Serum for Face Hair Scalp 1g