Amazon.com: Neurogan GHK Cu Copper Peptide Hair & Scalp Serum 2400mg, 4% Copper Peptides Fast Absorbing, Water Based Formula for Hair Softness & Shine Cosmetic Dry Scalp Moisturizer Spray, Made in USA : GHK Cu Copper Peptide Hair Tonic for Fuller Looking Hair 12 Week Supply (30 mL) Not all hair serums are built the same This one is powered by a dual copper peptide system GHK Cu + AHK Cu Designed to support: stronger feeling hair improved elasticity AHK Cu Peptide, Hair Elixir 4800mg