What is Sodium Metasilicate?

What is Sodium Metasilicate?

This is part of our ongoing series to help consumers better understand chemicals, chemistry, and product formulations. We translate the science, bust the myths, and give you an honest assessment, so you can make informed choices for your family!


Sodium Metasilicate

What it is:

Sodium metasilicate is created by fusing sodium carbonate with silica sand at about 1400 degrees celsius (1). Three quick facts for your scientific enjoyment:

  • If you heat baking soda (a.k.a. sodium bicarbonate) in a 400°F oven for about an hour, it releases carbon dioxide and water and turns into sodium carbonate (2).
  • Silica sand is quartz that’s been broken down into tiny granules through years and years and years of wind and water erosion (3). People purify this sand for commercial use to make things like glass.
  • How hot does it need to be to fuse these two elements? Extremely. To give you a sense of how hot 1400 degrees celsius is — lava, by comparison, is typically 700 to 1200 degrees celsius (4).

What it does:

Sodium metasilicate softens water and enhances cleaning performance and efficiency (5,6).

Why we use it:

We chose sodium metasilicate for our Dishwasher Packs and 4-in-1 Laundry Packs because it’s not only effective, but it’s also very mild – the U.S. Food and Drug Administration even lists it as a Generally Recognized as Safe (GRAS) direct food substance (6,7).


  1. Pentahydrate, S. M., & Nonahydrate, S. M. (2002). Review of Toxicological Literature. North Carolina, National Institute of Environmental Health Sciences, 23-25.
  2. What happens when sodium bicarbonate is heated? (n.d.). December 28, 2015, from http://antoine.frostburg.edu/chem/senese/101/inorganic/faq/carbonate-decomposition.shtml
  3. Goffer, Z. (2006). Archaeological chemistry (Vol. 170). John Wiley & Sons.
  4. Volcano World. (n.d.). Retrieved December 28, 2015, from http://volcano.oregonstate.edu/how-hot-lava
  5. Baker, C. L. (1931). Detergent value of sodium metasilicate. Industrial & Engineering Chemistry, 23(9), 1025-1032.
  6. Elmore, A. R. (2004). Final report on the safety assessment of potassium silicate, sodium metasilicate, and sodium silicate. International journal of toxicology, 24, 103-117.
  7. CFR - Code of Federal Regulations Title 21. (n.d.). Retrieved January 08, 2016, from https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=184.1769a

This post was revised as of 1/26/2016.

We aim to provide you with the most honest and credible information possible. This article was reviewed for accuracy by The Honest Team and was written based on trusted sources that are linked at the bottom of the article.