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 Copper Peptide Skincare Routine: How to Layer Peptides Glimmer Goddess GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B Neurogan Health, Copper Peptide GHK CU, 120 mcg, 60 Tablets iHerb GHK Cu Reconstitution & Stack Questions (Need Advice) : r PeptideDiscussion