GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? 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 Squalane + Copper Peptide (GHK Cu) Rapid Plumping Serum Biossance GHK Cu Organic Serum Copper Peptide for Anti Aging & Skin Repair