Copper Peptide (GHK Cu): Clinical Uses, Stability & Compounding Tips GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? Four reasons this serum belongs in your routine. GHK Cu Peptides that firm and support collagen renewal. Barrier support to keep your skin healthy and resilient. No injection. No needles. No clinic visit. GHK Copper Peptide GHK Cu Tripeptide 1 GHK Cu Side Effects, Complications, and Risk Profile