Tetrazolium Red is widely used in biological and biochemical research as a vital stain to assess cell viability. It is particularly valuable in experiments involving living cells, where it helps differentiate between metabolically active and inactive cells. The compound is reduced by dehydrogenases in living cells, forming a colored formazan product, which can be quantified spectrophotometrically. This property makes it a key tool in cytotoxicity assays, drug screening, and studies on cell proliferation. Additionally, it is employed in seed viability testing, where it helps determine the germination potential of seeds by staining live tissue. Its application extends to microbiology for evaluating microbial activity in environmental samples.