GHK

GHK (Glycyl-L-histidyl-L-lysine) is a naturally occurring human tripeptide found in plasma, saliva, and urine. It is the copper-free precursor to GHK-Cu and retains significant biological activity on its own. Plasma levels decline from ~200 ng/mL at age 20 to ~80 ng/mL by age 60, contributing to age-related decline in tissue repair and regeneration.

GHK chelates copper ions to form GHK-Cu, delivering bioavailable copper to sites of tissue injury. It upregulates collagen and glycosaminoglycan synthesis in dermal fibroblasts, promotes angiogenesis, and activates the FAK-paxillin signaling pathway critical for cell migration. Gene expression studies show GHK modulates over 4,000 human genes, including those governing DNA repair, mitochondrial biogenesis, anti-inflammatory signaling, and suppression of cancer-associated pathways such as TGF-β overactivation.

Preclinical studies demonstrate GHK stimulates collagen and elastin production at concentrations as low as 1 nM in human dermal fibroblasts. Animal wound healing studies suggest systemic efficacy at approximately 75–100 mg (human-equivalent). Large-scale gene array analyses by Pickart et al. identified broad anti-aging transcriptional effects. Human clinical evidence is limited primarily to topical cosmetic formulations.

Peptides commonly paired with GHK for synergistic effects.