AHK CU + GHK CU Hair Serum Pro YanaSecrets 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 Our peptide haircare and skincare collection is finally complete! The newest addition, our Dual Copper Peptide Hair Serum with AHK Cu + GHK Cu, is now available for pre order and completes the full AHK Cu vs. GHK Cu Peptides: Key Differences in Copper Mediated Signaling Research