AHK-cu (L-alanyl-L-histidyl-L-lysine) is a tripeptide used in laboratory research to investigate peptide-mediated signaling pathways, gene expression modulation, and cellular protein regulation. In vitro applications include studies on its influence on extracellular matrix dynamics, protein turnover, and oxidative stress–related pathways. AHK also serves as a reference compound in biochemical assays exploring peptide stability, degradation kinetics, and interactions with metal ions and enzymes. Additionally, it is utilized in analytical method development, including chromatography and mass spectrometry, due to its well-defined structure and reproducible behavior under controlled experimental conditions.