The tripeptide GHKCu complex ameliorates lipopolysaccharideinduced acute lung injury in mice Oncotarget Molecular structure of the tripeptide GHK Cu. In solution lysine Download Scientific Diagram 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 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 GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective?