Used in metabolic research to trace carnitine metabolism pathways, particularly in fatty acid oxidation studies. Its deuterated methyl group allows for precise tracking using mass spectrometry or NMR, enabling detailed analysis of metabolic flux in biological systems. Commonly applied in studies related to mitochondrial function and energy metabolism, especially in cardiac and skeletal muscle tissues. Also utilized in pharmacokinetic studies to assess absorption, distribution, and clearance of carnitine derivatives in drug development.