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 pHA measurement of the acidity or basicity of a substance. pH is the negative logarithm (base 10) of the concentration of hydrogen ions in solution. Water has a concentration of hydrogen ions of 1.0 x 10-7, and thus has a pH of 7. A pH of 7 is considered neutral, a pH lower than 7 is considered acidic, and a pH higher than 7 is considered basic. 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“GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.). 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 inhibitorIngredients that prevent the corrosion (rust) of metallic materials used in cosmetic packaging. 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 ReviewThe Cosmetic Ingredient Review (CIR) was established in 1976 as an independent safety review program for cosmetic ingredients. The CIR Expert Panel consists of independent experts in dermatology, toxicology, pharmacolgy and veterinary medicine. The CIR includes participation by the U.S. Food & Drug Administration and the Consumer Federation of America. (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 UnionUnder the general provisions of the cosmetics regulation of the EU, ingredients appearing on the following function-specific annexes must comply with the listed restrictions and/or specifications: colorants (Annex IV), preservatives (Annex V), UV filters (Annex VI) and other ingredients with specific concentration limits and/or other restrictions (Annex III). Ingredients specifically prohibited from use in cosmetic products are listed in Annex II. Other ingredients listed in the EU cosmetic ingredient database (CosIng) may be used without restrictions..

Link to the EU Cosmetic Regulation:
http://europa.eu/legislation_summaries/consumers/product_labelling_and_p…

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.
http://www.inchem.org/documents/jecfa/jecmono/v05je04.htm

More Scientific Information

Sodium Silicate is formed when metal cations (sodium) combine with silica. Sodium Silicate functions as a buffering agentIngredients that minimize the change in the pH of a solution when an acid or a base is added to the solution., corrosion inhibitor and a pH adjusterIngredients that are used to control the pH of cosmetic products. 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.

Resources

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

Food Ingredients and Packaging: http://www.fda.gov/Food/IngredientsPackagingLabeling/default.htm

Food Contact Substances: http://www.fda.gov/Food/IngredientsPackagingLabeling/PackagingFCS/defaul…

Substances Generally Recognized As Safe (GRAS): http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/default.htm

Search the Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm

EU Cosmetics Inventory http://ec.europa.eu/consumers/cosmetics/cosing/