GHK Cu for Hair Growth: Before and After Results and Dosage If you've been seeing copper peptides everywhere lately this is the one they're usually talking about. GHK Cu has been studied for its role in skin recovery and follicle support, which is Copper Peptide Hair Growth Serum 10% GHK Cu & 5% AHK Cu Hairgenetix Copper Peptide 10% GHK CU, 5% AHK CU with Oligopeptide 1 Hair Treatment Serum Neurogan Health, GHK Cu Copper Peptide, Hair & Scalp Serum Copper Peptide Hair Growth Serum AHK Cu & GHK Cu + Licorice Peptide Labz