The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline 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 Copper Peptide Hair Regrowth Formula GHK CU AHK CU: Real Results for Thinning Hair in Men and Women Copper Peptide 10% GHK CU, 5% AHK CU with Oligopeptide 1 Hair Treatment Serum eBay