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 Copper Peptide Hair Growth Serum for Hair Loss & Thinning Hair Feline Skinscience GHK CU Copper Peptide, Hair & Scalp Serum, 2 oz (60 ml) Copper Peptide GHK CU Conditioner for Hair Growth Mall of California Advanced Copper Peptide Hair Regrowth Formula GHK CU & AHK CU, Copper Peptide Hair Growth Treatment Serum For Men Women Walmart.ca