Used as a vital reagent in cell viability and proliferation assays. It is reduced by metabolically active cells to formazan, a purple-colored compound that can be quantified spectrophotometrically after solubilization. This property makes it ideal for assessing cell health in cytotoxicity, drug screening, and antimicrobial activity studies. Commonly applied in research laboratories for evaluating the effects of pharmaceuticals, environmental toxins, and experimental treatments on living cells. Also utilized in microbiology to determine microbial activity and in cancer research for testing chemotherapeutic agents.