GHK Cu isn't just' a skin peptide. The gene expression data is why it keeps showing up in longevity reviews. Follow @lebaneselabs for daily peptide research. 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: GHK Cu Copper Peptide Supplement, 120mcg High Purity Supplement for Skin & Hair, Enteric Coated for Maximum Absorption, Vegan & Gluten Free (60 Count) : Health & Household GHK Cu Peptide: Benefits for Tissue Repair, Healing, and Recovery Revolution Health & Wellness 7% GHK Cu Accelerant Private Label Advanced GHK Cu Copper Peptide Face Cream Anti Age Improve Elasticity Blue GHK Copper Peptides Powder Moisturizer