Skin Restoration: Prioritizing Safety Over Trends GHK Cu: My secret weapon for skin, hair, and healing, I use it two ways topical cream for my face, and subQ injections 3x a week., It boosts collagen, tightens skin, helps hair grow, and even 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 All About GHK Cu Peptide More Than Just Cosmetic Subcutaneous Injection: What It Is and How to Give One