Succinic acid-d6 is widely used as an internal standard in nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) for quantitative analysis. Its deuterated form ensures minimal interference with the sample, providing accurate measurements in studies involving metabolic pathways and biochemical processes. It is particularly valuable in tracing and analyzing the Krebs cycle in biological systems, aiding in research on cellular respiration and energy production. Additionally, it finds application in pharmaceutical research for drug metabolism studies, helping to identify and quantify metabolites in complex biological matrices. Its stability and isotopic purity make it a reliable tool in advanced analytical chemistry.