Effects of Copper Tripeptide on the Growth and Expression of Growth Factors by Normal and Irradiated Fibroblasts Jeffrey D. Pollard, Susan Quan, Thomas Kang, R. James Koch, 2005 GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? Amazon.com: GHK Cu Copper Peptide Powder 99.7%+ Pure Cosmetic Grade Ingredient for DIY Serums, Creams & Scalp Tonics Supports Collagen & Fuller Hair (1g) : Beauty & Personal Care The naturally occurring peptide GHK reverses age related fibrosis by modulating myofibroblast function He Aging Pathobiology and Therapeutics GHK Cu is a naturally occurring tripeptide in human plasma. Levels average 200 ng ml at age 20 and drop to 80 ng ml by age 60 (Pickart et al., 2020). That decline tracks with Relief of ovalbumin induced airway remodeling by the glycyl l histidyl l lysine Cu2+ tripeptide complex via activation of SIRT1 in airway epithelial cells ScienceDirect