Cambridge Isotope Laboratories, Inc. (CIL)  is the world’s leading producer of stable isotopes and stable isotope-labeled compounds. With over 500 employees and laboratories in four countries, CIL specializes in the process of labeling biochemical and organic compounds with highly enriched, stable (nonradioactive) isotopes of carbon, hydrogen, nitrogen and oxygen. Our chemists substitute common atoms (e.g., ¹H, ¹²C, ¹⁴N, ¹⁶O) with rare, highly valued isotopes (e.g., ²H or D, ¹³C, ¹⁵N, ¹⁸O) so that the final product can be readily measured or traced using mass spectrometry (MS) or nuclear magnetic resonance (NMR). CIL’s products are utilized in laboratories, medical, government and academic research centers and health care facilities worldwide.