Used as a nutritional supplement to support selenium intake, particularly in research settings where isotopic labeling is needed. Employed in studies involving antioxidant mechanisms due to selenium's role in glutathione peroxidase activity. Applied in cell culture media to investigate selenium metabolism and its impact on protein synthesis, since it can be incorporated into proteins in place of methionine. Also utilized in radiolabeling and tracer studies for tracking metabolic pathways and selenium bioavailability.