GHK Cu for Hair Growth? It Works But Only If You Do It Right. Everyone's talking about GHK Cu, but here's the catch most serums never make it past your scalp barrier. GHK CU Cream Amazon.com : Scalp Exosomes with Growth Factor Peptides (EGF & IGF), GHK Cu, and Hyaluronic Acid Topical Hair & Scalp Rejuvenation. Made in Korea. (100 mg Exosomes + 5 mL Peptide Solution) : Copper Peptide Hair Growth Serum 10% GHK Cu & 5% AHK Cu Hairgenetix