Widely used in biological and biochemical assays as an electron acceptor in dehydrogenase enzyme reactions. It serves as a vital component in cell viability and cytotoxicity tests, where metabolically active cells reduce it to a red-colored formazan product. This color change allows for easy quantification of cellular activity in assays such as MTT or similar tetrazolium-based tests. Commonly applied in drug screening, toxicity studies, and research involving mitochondrial function. Its ability to penetrate cell membranes and undergo enzymatic reduction makes it valuable for detecting live cells in high-throughput screening and microbiological testing.