The Cell Meter™ Colorimetric Cellular Senescence Activity Assay Kit is an easy-to-use method for detecting senescent cells in culture. Cellular senescence is a natural process in which actively dividing cells transition into a permanent, non-dividing state, often associated with aging. Senescence is accompanied by morphological changes, altered gene expression, and distinct physical characteristics. Over time, senescent cells typically progress toward cell death, although they can remain metabolically active for extended periods. This kit utilizes the Xite™ beta-D-galactopyranoside substrate to enable the visualization of β-galactosidase activity, a key biomarker of cellular senescence, forming a with a distinct blue color as seen under a standard light microscope. It includes all necessary reagents for fixation, staining, and detection, ensuring high reproducibility. The simple workflow involves a straightforward incubation and washing process, allowing researchers to achieve reliable results without requiring fluorescence microscopy or specialized equipment. It is ideal for studying aging, cellular stress, and drug-induced senescence in cells.