Sodium Silicate

What Is It?

Sodium Silicate, Sodium Metasilicate and Potassium Silicate are an inorganic salts. In cosmetics and personal care products, these ingredients are used in skin care, hair coloring, shaving, bath, eyemakeup and oral hygiene products.

Why Is It Used?

Sodium Silicate is used to control the pH of the finished product. Sodium Silicate, Sodium Metasilicate and Potassium Silicate are also used to prevent the corrosion (rust) of metallic materials used in cosmetic packaging.

Scientific Facts

Sodium Silicate is produced through a reaction of silica sand and sodium carbonate, sometimes referred to as “liquid glass.” The principle use of Sodium Silicate is in the manufacture of soaps and detergents, where it provides a constant pH value.

Safety Information

The Food and Drug Administration (FDA) includes Sodium Metasilicate on its list of direct food substances affirmed as Generally Recognized As Safe (GRAS). In food, Sodium Metasilicate is used as a processing aid, and in the washing and peeling of fruits, vegetables and nuts. It is also used as a corrosion inhibitor in canned and bottled water. Sodium Silicate is on the list of indirect food additives considered GRAS as a substance migrating to food from packaging materials.

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of Sodium Silicate, Sodium Metasilicate and Potassium Silicate. The CIR Expert Panel concluded that when formulated to avoid irritation, all three ingredients were safe for use in cosmetic products in the practices of use and concentrations described in the safety assessment.

CIR Safety Review: The CIR Expert Panel determined that the data provided in its report were sufficient to address the safety of the tested ingredients Potassium Silicate, Sodium Metasilicate and Sodium Silicate. The CIR Expert Panel recognized the irritation potential of these ingredients, especially in leave-on products. However, because these ingredients have limited dermal absorption and Sodium Metasilicate is a GRAS direct-food substance, the CIR Expert Panel deemed the ingredients safe as currently used when formulated to avoid irritation.

FDA: Link to the Code of Federal Regulations for Metasilicate and Sodium Silicate

Sodium Silicate, Sodium Metasilicate and Potassium Silicate may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European Union.

Link to the EU Cosmetic Regulation:…

The Joint FAO/WHO Expert Committee on Food Additives has not established a limit for the Acceptable Daily Intake of Silicon dioxide and certain silicates except Magnesium Silicate and Talc.

More Scientific Information

Sodium Silicate is formed when metal cations (sodium) combine with silica. Sodium Silicate functions as a buffering agent, corrosion inhibitor and a pH adjuster in cosmetics. Buffering agents, commonly called buffers, are chemicals which have the property of maintaining the pH of an aqueous medium in a narrow range even if small amounts of acids or bases are added. Buffering agents and pH adjusters are used in cosmetics to alter and maintain a product’s pH at the desired level.


Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging:

Food Contact Substances:…

Substances Generally Recognized As Safe (GRAS):

Search the Code of Federal Regulations

EU Cosmetics Inventory