What Are GHK Cu Peptides for Skin and Hair Health? When your hair feels stronger, you do too. The Hairgenetix Extra Strength Copper Peptide Serum, formulated with 10% GHK Cu and 5% AHK Cu, supports hair health at the root helping strengthen follicles, Small molecules. Powerful results. Experience Peptide Power with Hairgenetix's advanced Copper Peptide Hair Growth Serum, formulated with 10% GHK Cu and 5% AHK Cu to support hair health at the follicle level. Helps 2% GHK CU Copper Peptide Serum for Hair Growth and Scalp Care Seraphime