Widely used in biological assays to assess cell viability and metabolic activity. It serves as an indicator in tetrazolium-based assays, where living cells reduce it to a red-colored formazan product through dehydrogenase enzymes. This color change allows quantification of cell proliferation, cytotoxicity, and apoptosis in cell cultures. Commonly applied in drug screening, toxicity testing, and microbiology to evaluate the effect of compounds on cellular metabolism. Also used in plant physiology to study root activity and in microbiology for bacterial viability detection. Its ability to penetrate cells and produce a stable colored product makes it suitable for both manual and automated high-throughput screening methods.