Subcutaneous Injection Sites and Instructions for Safe Self Administration 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 Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy GHK Cu 100mg Peptide Pen Bioniq Lab Peptides Made Personal