GHK Cu Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline 7 days on GHK Cu. Here's my honest update. I'm not going to hype this up because the real results don't even start until week 46. But something is already happening. Fitish Most people don't know GHK Cu by name. Their face does. It's the peptide your body uses to signal collagen production, repair tissue, Instagram