GHK Cu 50 mg Copper Peptide Research Grade PRG GHK Cu Youthful Skin, Healthy Cells, Vibrant You. Now introducing one of my favorite peptides.. GHK Cu This is a naturally occurring copper peptide your body already uses to repair and regenerate skin. As we age, those levels decline and that's GHK Cu, commonly known as copper peptides, are found naturally within the human body where they play a vital role in skin repair and maintenance. Copper peptides support optimal skin function by helping