GHK-Cu (glycyl-L-histidyl-L-lysine copper) is a naturally occurring tripeptide-copper complex, with the molecular formula C₁₄H₂₄N₆O₄Cu, found in human plasma, saliva, and urine, known for its role in tissue repair, anti-inflammatory, and regenerative processes. The tripeptide GHK (glycyl-L-histidyl-L-lysine) binds copper (II) ions with high affinity, forming a stable complex that modulates over 4,000 genes involved in wound healing, collagen and elastin synthesis, and antioxidant defense by activating pathways such as TGF-β and VEGF, while inhibiting pro-inflammatory cytokines like IL-6 and TNF-α. GHK-Cu promotes angiogenesis, fibroblast proliferation, and extracellular matrix remodeling, making it a candidate for applications in skin rejuvenation, hair growth, and tissue repair, with studies showing enhanced wound closure rates and reduced scarring in animal models. Administered topically, subcutaneously, or intravenously in experimental settings, it exhibits low toxicity but is not FDA-approved for clinical use, with research ongoing into its potential in anti-aging, neurodegenerative disorders, and chronic wounds, though human clinical data remain limited and optimal dosing strategies are under investigation.