Your body made this peptide every day until you turned 30. Then it stopped. GHK Cu (copper peptide) is a naturally occurring tripeptide discovered in 1973. At age 20, your plasma levels sit Rational modification of PROTACs for tumor selective protein degradation ScienceDirect Nanoengineered Self Assembling Peptides with Increased Proteolytic Stability Promote Wound Healing ACS Applied Materials & Interfaces In Vitro and in Vivo Studies of pH Sensitive GHK Cu Incorporated Polyaspartic and Polyacrylic Acid Superabsorbent Polymer ACS Omega