GHK CU: How to Mix It The Peptide Report 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 Amazon.com: Skin Perfection Copper Peptide Serum GHK CU 1% for Face & Hair Copper Peptides for Skin, Hair, & Scalp 1% Blue Liquid for Face, Neck, Body, Scalp Multi Use Serum Booster with Topical GHK Cu Cream : r Peptides_for_Women Reducing Redness & Inflammation with GHK Cu Copper Peptides Vitali Skincare