Copper, Collagen, and Controversy: Inside the GHK Cu Buzz Before vs. after 3 months of GHK Cu peptide therapy smoother texture, more even tone, and skin that looks healthier overall. Small peptide, big difference Rejuvenation and Youth with GHK Cu Peptide Treatment Dr. Ahmet zyigit The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline