GHK Cu (copper peptide) used topically is one of the most well studied skin repair peptides. Here's how it helps the skin, in practical terms: 1. Boosts collagen & elastin GHK Cu signals your skin GHK Cu Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy GHK Cu Dosage and Protocol: A Medical Provider's Guide to the 30 Day Cycle Perfect B The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Officially started my "copper uglies" phase of GHK CU, phase is NOT for the weak. No pin pain, but my skin is purging and I hate it