D-Tryptophan is primarily used in research and pharmaceutical applications. It serves as a chiral building block in the synthesis of various biologically active compounds, including peptides and pharmaceuticals. In biochemical studies, it is employed to investigate enzyme mechanisms and protein interactions due to its role as a precursor in metabolic pathways. Additionally, D-Tryptophan is utilized in the development of drugs targeting neurological disorders, as it influences serotonin and melatonin production. Its enantiomeric properties make it valuable in asymmetric synthesis and the study of stereochemical effects in drug design.