GHK Cu: The Regenerative Peptide for Skin, Hair, and Healing Pulse & Remedy 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 Growth Hormone and Aging Endotext NCBI Bookshelf GHK Cu Copper Peptide Therapy Chicago Better Med Spa The tripeptide GHKCu complex ameliorates lipopolysaccharideinduced acute lung injury in mice Oncotarget