GHK Cu Peptide Therapy Collagen & Skin Renewal GHK Cu Hair Growth 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 Fitish Most people don't know GHK Cu by name. Their face does. It's the peptide your body uses to signal collagen production, repair tissue, Instagram GHK Cu Copper Peptide Benefits, Uses & Safety Intra V