Stable isotope labeling involves the use of non-radioactive isotopes that can act as a tracers used to model several chemical and biochemical systems. The chosen isotope can act as a label on that compound that can be identified through nuclear magnetic resonance (NMR) and mass spectrometry (MS). Some of the most common stable isotopes are H, C, and N, which can further be produced into NMR solvents, amino acids, nucleic acids, lipids, common metabolites and cell growth media. The compounds produced using stable isotopes are either specified by the percentage of labeled isotopes (i.e. 30% uniformly labeled C glucose contains a mixture that is 30% labeled with carbon isotope and 70% naturally labeled carbon) or by the specifically labeled carbon positions on the compound (i.e. 1- C glucose which is labeled at the first carbon position of glucose).