Glycyl-L-phenylalanine is primarily used in biochemical research as a substrate to study enzyme activity, particularly for enzymes like dipeptidyl peptidase IV (DPP-IV). It helps in understanding the mechanisms of peptide bond cleavage and enzyme kinetics. Additionally, it is utilized in the development of therapeutic agents targeting metabolic disorders, such as diabetes, due to its role in DPP-IV inhibition. In cosmetic formulations, it serves as a peptide ingredient to enhance skin hydration and improve elasticity. Its application in nutritional supplements focuses on promoting muscle recovery and overall health due to its peptide structure.