Used as a stable isotope-labeled internal standard in mass spectrometry and nuclear magnetic resonance (NMR) studies to trace metabolic pathways involving amino acids. Enables precise quantification and monitoring of serine metabolism in biological systems, particularly in research on one-carbon metabolism, neurotransmitter synthesis, and cancer cell metabolism. Supports studies in proteomics and metabolomics where high sensitivity and accuracy in detection are required. Also employed in stable isotope labeling by amino acids in cell culture (SILAC) for quantitative proteomics.