Copper peptides (GHK Cu) have been studied for decades for their role in tissue repair and that same biology applies to hair. Research shows GHK Cu may help strengthen existing hair follicles, reduce Amazon.com: Copper Peptide Hair Serum with Copper Tripeptide 1 Dual Peptide Scalp Treatment plus Licorice Root Extract : Beauty & Personal Care Mayraki Hair Growth Serum Intense with Copper Peptide GHK Cu Hair Growth Serum for Woman and Man, Hair Growth Oil, Hair Regrowth Treatment, Hair GHK Cu Copper Peptide Anti Aging Toner I'm Fabulous Cosmetics