GHK CU Peptide for Skin Rejuvenation Wittmer Rejuvenation Clinic This peptide reverses aging, And its been hiding in plain sight for decades., GHK Cu (Copper Peptide) is one of the most researched anti aging ingredients out there., Heres what it does:, GHK Cu 50mg Particle Peptides Turn Back Time with GHK CU Peptides Meet one of the most powerful anti aging peptides in skincare GHK CU. This advanced peptide helps to: Tighten and firm loose skin