Neurogan + Health GHK CU Copper Peptide Hair and Scalp Serum PrettyStick GHK CU 107MG Thrive Peptides Advanced GHK CU + AHK CU Peptide Hair Growth Serum 30ml Azur Skin GHK CU Warrior Peptides The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds, Copper Peptide Serum for Hair Regrowth & Thinning Hair Feline Skinscience