Can GHK Cu Copper Peptide Tighten Skin After Weight Loss? Peptides for Hair Growth: promising, but not magic., Hair growth is not controlled by one single factor. It depends on the hair cycle, follicle health, blood supply, inflammation, hormones, How GHK Peptide Works Signaling GHK acts as a switch for skin repair: Interacts with adenosine receptors reduces inflammation Activates MAPK ERK, PI3K Akt, TGF pathways Stimulates fibroblasts & keratinocytes boosts collagen, elastin Ingredients Hairgenetix GHK Cu, AHK Cu & PDRN Peptides