D-Glutamine, the D-enantiomer of the amino acid glutamine, is primarily used in biochemical and molecular biology research. Unlike the biologically common L-glutamine, it serves as a specialized tool to investigate enzyme stereospecificity, chiral recognition, and the differential metabolism of D- versus L-amino acids. It is employed in studies of amino acid transport, protein synthesis pathways, and enzyme function, where its non-natural configuration helps distinguish activities specific to L-forms. D-Glutamine is also utilized in specialized cell culture media to examine the effects of D-amino acids on cellular growth and viability, particularly in comparative studies. In microbiology, it supports the cultivation of select organisms capable of utilizing D-amino acids. Furthermore, it plays a role in neuroscience research, exploring potential influences on neurotransmitter regulation and D-amino acid signaling in the brain. Its niche applications make it essential for advancing understanding in chirality-dependent biological processes.