Copper Peptides for Skin: A Complete Guide Neurogan GHK Cu (Copper Peptide) Neck & Face Serum 1200mcg (1 oz bottle) You started using a GHK Cu peptide serum on your face and now , The things no one tells you., Yes, the injections can hurt like a bitch. , Heres the thing Ive found it works even better topically, Neurogan Health, copper peptide GHK CU, 120 mcg, 60 tablets iHerb GHK Cu Peptide Therapy Pricing Cellular Glow Copper Peptide GHK Cu Serum for Face