GHK Cu Peptide: What It Does for Body Composition and Metabolic Health Topical or SubQ GHK Cu? Same molecule. Very different purposes. Topical you apply it on your skin. Think of it as feeding your skin from the outside. In a 12 week study of GHK Cu Glow Peptide Stack for Skin Rejuvenation Jennifer R. Berman MD Rejuvenation and Youth with GHK Cu Peptide Treatment Dr. Ahmet zyigit Copper peptide questions we get asked all the time How often should you use it? Do you need to avoid the sun? If you're new, start once daily (evenings are great),