Used in pharmaceutical research and development, particularly in the synthesis of deuterated peptides and proteins. The deuterated phenyl group enhances metabolic stability and allows for tracking in biological systems using mass spectrometry or NMR. Commonly employed in isotopic labeling studies to investigate drug metabolism, pharmacokinetics, and mechanistic pathways. Its BOC-protected amino acid structure makes it suitable for solid-phase and solution-phase peptide synthesis, where the deuterium label serves as an internal standard in quantitative assays. Also utilized in studies requiring improved analytical detection limits due to the distinct mass signature of deuterium.