GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? GHK Cu: The Regenerative Peptide for Skin, Hair, and Healing Pulse & Remedy Growth Hormone and Aging Endotext NCBI Bookshelf The naturally occurring peptide GHK reverses age related fibrosis by modulating myofibroblast function He Aging Pathobiology and Therapeutics By age 30, your skin produces about 25% less collagen. By 40, that number can reach 40%. This decline affects more than just how your skin looks. It changes how it heals, Relief of ovalbumin induced airway remodeling by the glycyl l histidyl l lysine Cu2+ tripeptide complex via activation of SIRT1 in airway epithelial cells ScienceDirect