GHK-Cu (copper peptide) is a tripeptide consisting of glycine, histidine, and lysine, with a strong binding affinity for copper(II) ions. It was first identified in human plasma and has since been detected in saliva and urine. The peptide-copper complex is studied in laboratory environments as a model for understanding metal ion–peptide interactions and their influence on extracellular matrix biology. In preclinical research, GHK-Cu has been examined for its effects on fibroblast behavior, including collagen synthesis, glycosaminoglycan production, and decorin expression in in-vitro culture systems. Experimental data describe modulation of matrix metalloproteinase (MMP) activity and cellular structure inhibitor of metalloproteinase (TIMP) expression, positioning the peptide as a probe for studying ECM turnover dynamics. Additional laboratory investigations reference GHK-Cu in studies of gene expression modulation, with microarray analyses identifying broad transcriptional changes in pathways associated with antioxidant response, DNA repair signaling, and inflammatory mediator regulation. Sequence: Gly-His-Lys:Cu²⁺ Molecular Formula: C₁₄H₂₃CuN₆O₄ Molecular Weight: 403.92 g/mol CAS: 49557-75-7 For laboratory research use only. Not for human consumption.