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 Am+Pm 5% B5+GHK Cu Hydrating Serum Amazon.com: Neurogan GHK Cu (Copper Peptide) Neck & Face Serum 1,200mcg (1 oz bottle) : Beauty & Personal Care Elevate Supplements GHK Cu Copper Peptide Serum HardCore Supplements Skin Perfection GHK Cu Copper Peptide Serum Booster, 1 Percent Blue Liquid For Face, Neck, Body, Hair, And Scalp, 0.5 oz Walmart.com