PDF) The effect of tripeptide copper complex on human hair growth in vitro GHK Cu for Hair Growth? It Works But Only If You Do It Right. Everyones talking about GHK Cu, but heres the catch most serums never make it past your scalp barrier. If the formulas too weak, it GHK CU Hair Loss & Regrowth Treatment Therapy Vitality Health Copper Peptide 10% GHK CU, 5% AHK CU with Oligopeptide 1 Hair Treatment Serum eBay