Amazon.com: Neurogan GHK Cu (Copper Peptide) Neck & Face Serum 1,200mcg (1 oz bottle) : Beauty & Personal Care GHK CU Copper Peptide, Hair & Scalp Serum, 2 oz (60 ml) Amazon.com: Neurogan GHK Cu + AHK Cu Hair Serum Pro Lightweight Scalp Serum with Dual Copper Peptides Daily Hair & Scalp Use, Cosmetic Product : Beauty & Personal Care 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 GHK Cu Copper Peptide Hair Tonic for Fuller Looking Hair 12 Week Supply (30 mL)