Natural Copper Peptide Serum Booster Advanced GHK Cu Face Cream 2400mg 4% Firmer Skin Neurogan Neurogan Health Not all Copper Peptides are created equal If you've tried copper peptides before and saw no change, here is why: Concentration and Stability. Most serums use a diluted solution that barely scratches 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 For Sale (200mg) Core Peptides 7% GHK Cu Cosmetic Ingredient Accelerant Skin Biology 15 ml