Cellular Glow Copper Peptide GHK Cu Serum for Face Do Nasal Spray Peptides Work? Intranasal vs Injectable Peptides Glutathione Vs Other Skin Brightening Treatments Explained GHK CU Copper Peptide Recovery Peptide Suppstance The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds,