Cell Counting Kit

Accurate and efficient quantification of viable cells is essential for evaluating cell proliferation, cytotoxicity, and drug effects in vitro. Our Cell Counting Kit-8 (CCK-8) provides a simple, reliable, and highly sensitive colorimetric method for determining viable cell numbers in a wide variety of cell-based assays.

Utilizing a water-soluble tetrazolium salt (WST-8), the CCK-8 kit enables non-radioactive and reproducible analysis of cell viability. It is ideal for high-throughput screening, cytotoxicity testing, and long-term proliferation studies.

Key Features:

No radioactivity – safe, non-toxic assay for routine lab use
Ready-to-use – one-bottle solution, no mixing or preparation required
High sensitivity and reproducibility
Low-cytotoxicity – allows longer incubation and additional downstream assays
Colorimetric readout – compatible with standard plate readers
Ideal for high-throughput screening in 96- and 384-well formats

How It Works:

The CCK-8 assay is based on the reduction of WST-8, a tetrazolium salt, by cellular dehydrogenases present in metabolically active cells. This reaction produces a water-soluble orange formazan dye, the intensity of which correlates directly with the number of viable cells. The dye remains in the culture medium and can be measured directly by absorbance at 450 nm, without the need for additional steps such as solubilization or washing.

Because the CCK-8 reagent has low toxicity and is stable, extended incubation (up to 24–48 hours) is possible—making it ideal for time-course and long-term viability assays.