GHK Cu Hair Growth The Peptide Craze Ground Truths GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? 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. GHK Cu as a multifunctional copper peptide: synthesis routes, process engineering and emerging applications Systems Microbiology and Biomanufacturing Springer Nature Link Peptide Therapy for Pain Management and Healing Core Medical & Wellness