Used extensively in neuroscience research, it serves as a stable isotope-labeled internal standard in mass spectrometry for the quantification of endogenous γ-aminobutyric acid (GABA) levels in biological samples. This application is crucial for studies investigating GABA's role in neurological disorders such as epilepsy, anxiety, and depression. Additionally, it aids in pharmacokinetic studies to understand the metabolism and distribution of GABA-related drugs. Its deuterated form ensures accurate and reliable measurements by minimizing interference from endogenous compounds.