Cell Proliferation Reagent WST-1

cell proliferation reagent, wst-1

Quality Level




sufficient for ≤2,500 tests (11644807001)
sufficient for ≤800 tests (05015944001)


bottle of 25 mL (11644807001)
bottle of 8 mL (05015944001)



storage condition

protect from light


cell analysis: suitable
detection: suitable
protein quantification: suitable

optimum pH

8.0(for physiological conditions our product is buffered pH 7.3)


440-480 nm

detection method


shipped in

dry ice

storage temp.


General description

Cellular proliferation requires the replication of genomic DNA. Thus, monitoring DNA synthesis is an indirect parameter of cell proliferation, as well as being suitable for the study of the regulation of DNA synthesis. [3H]-thymidine has traditionally been used to label the DNA of replicating (cycling) cells. To circumvent the disadvantages associated with the use of the [3H]-thymidine, nonradioactive alternatives based on 5-bromo-2′-deoxyuridine (BrdU) have been developed. The use of chemiluminescence technology provides enhanced sensitivity and a broad measurement range.
Ready-to-use solution, containing WST-1 and an electron coupling reagent.
Colorimetric assay (WST-1 based) for the nonradioactive quantification of cell proliferation, cell viability, and cytotoxicity.


The Cell Proliferation Reagent WST-1 is used for the nonradioactive, spectrophotometric quantification of cell proliferation and viability in cell populations using the 96-well-plate format. Measurement of cell proliferation in response to growth factors, cytokines, mitogens, and nutrients.
  • Analysis of cytotoxic and cytostatic compounds, such as anti-cancer drugs and other pharmaceutical compounds
  • Assessment of growth inhibitory antibodies and physiological mediators

Features and Benefits

  • Convenient: Benefit from a ready-to-use reagent.
  • Safe and Easy: Eliminate radioactive isotopes, washing steps, and additional reagents.
  • Accurate: The absorbance obtained strongly correlates to the cell number.
  • Sensitive: Detect low cell numbers.
  • Fast: Process a large number of samples using a multi-well ELISA reader.


The stable tetrazolium salt WST-1 is cleaved to a soluble formazan by a complex cellular mechanism that occurs primarily at the cell surface. This bioreduction is largely dependent on the glycolytic production of NAD(P)H in viable cells. Therefore, the amount of formazan dye formed directly correlates to the number of metabolically active cells in the culture.
Cells grown in a 96-well tissue culture plate are incubated with the WST-1 reagent for 0.5 - 4 hours. After this incubation period, the formazan dye formed is quantitated with a scanning multi-well spectrophotometer (ELISA reader). The measured absorbance directly correlates to the number of viable cells.
Cell proliferation and viability assays are of particular importance for routine applications in cell biology. Tetrazolium salts (e.g., MTT, XTT, WST-1) are particularly useful for this type of analysis. Tetrazolium salts are cleaved to formazan by the succinate-tetrazolium reductase system (EC which belongs to the respiratory chain of the mitochondria, and is only active in metabolically intact cells.

Preparation Note

Working concentration: For best results, add 10 μl/well Cell Proliferation Reagent WST-1 to the cells already cultured in 100 μl/well (1:10 final dilution).
Using the 100 μl/well cell culture volume, one vial will be sufficient to perform 2500 tests (25 microplates).
Note: If the cells are cultured in 200 μl/well, add 20 μl/well Cell Proliferation Reagent WST-1.
Storage conditions (working solution): 2 to 8 °C
Note: When precipitates or turbidity are observed upon thawing, warm up the solution to 37 °C for 2 to 10 minutes and agitate to dissolve the precipitates.Centrifugation is not recommended because the working concentration would decrease. After being dissolved, the WST-1 reagent can be used without any limitations. Please store as follows:
Once thawed, store at 2 to 8 °C, protected from light, for up to four weeks. However please note that the solution may become viscous. If so, warm up the solution to 37 °C for 2 to 10 minutes as described above.

Long storage
For long storage, aliquots of WST-1 can be stored in plastic tubes at -15 to -25 °C until the expiry date.

Other Notes

For life science research only. Not for use in diagnostic procedures.


NONH for all modes of transport

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Cell based assays for cell proliferation (BrdU, MTT, WST1), cell viability and cytotoxicity experiments for applications in cancer, neuroscience and stem cell research.
Read More
WST-1 assay protocol for measuring cell viability, proliferation, activation and cytotoxicity. Instructions for WST-1 reagent preparation and examples of applications. Frequently asked questions and troubleshooting guide for WST-1 assay.
Read More

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