Copper Peptide Hair Growth Serum (GHK Cu & AHK Cu) COPPER PEPTIDES FOR HAIR GROWTH Ultrastrong 10% GHK Cu Formula with Sonora Supply Co. Support hair growth at the follicle level. GHK Cu is a copper peptide naturally produced by the body that plays a role in tissue repair, healing, and hair follicle activity. As levels decline GHK Cu Copper Peptide Hair Tonic for Fuller Looking Hair 12 Week Supply (30 mL)