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 Advanced GHK Cu Face Cream 2400mg 4% Firmer Skin Neurogan Neurogan Health 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 Am+Pm 5% B5+GHK Cu Hydrating Serum GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B