Stable isotopes such as Carbon-13 (13C), Nitrogen-15 (15N), and Deuterium (2H) are incorporated into cells or tissues through labeled compounds (e.g., amino acids, nucleotides). These compounds are introduced into the biological system, where they participate in normal cellular functions. The labeled molecules can then be tracked and analyzed using techniques like mass spectrometry and Nuclear Magnetic Resonance (NMR).
