What it is
Sodium metasilicate is an alkaline inorganic salt composed of sodium, silicon, and oxygen. In personal-care formulas it acts mainly as a pH adjuster and buffering agent, helping bring a formula to a target alkalinity, and it can also contribute mild water-conditioning or sequestering effects. It is typically present at low levels.
Safety & warnings
Sodium metasilicate is alkaline in concentrated form, so it is used at low levels and in pH-balanced finished products; in those finished formulas it is not expected to cause irritation. As an inorganic salt it is not comedogenic and is not a recognized fragrance allergen.
Origin & sourcing
Synthetic. It is an inorganic silicate salt manufactured from silica and sodium sources.
Questions everyone asks
What does sodium metasilicate do in a product?
It mainly adjusts and buffers pH toward the alkaline side and can help condition or sequester ions in the water phase.
Is it the same as silica?
No. It is a soluble alkaline sodium silicate salt, different from insoluble silica powder used as a texturizer or absorbent.