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 GHK Cu Topical Cream Neurogan Health, Copper Peptide GHK CU, 120 mcg, 60 Tablets iHerb After a year of using GHK Cu both topically and going deeper than topicals (under my doctor's care), the difference in my skin is not something I have to squint at in good