Synthetically Manufactured Amorphous Silica and Amorphous Silicates

Safety Information

U.S. Food and Drug Administration (FDA)

The FDA allows silica to be directly added to food as an anticaking agent. It is also permitted as an indirect food additive as a component of filters and polyester resins (21CFR177.2250 and 21CFR177.2420). Aluminum calcium sodium silicate (as sodium calcium aluminosilicate, hydrated) is considered Generally Recognized as Safe (GRAS) as anticaking agent in food.

Expert Panel for Cosmetic Ingredient Safety

The Expert Panel for Cosmetic Ingredient Safety reviewed the safety of aluminum slicate, calcium slicate and other silicates in 2003, concluding that these ingredients are safe as used in cosmetic products.  In 2005, potassium silicate, sodium metasilicate and sodium silicate were found to be safe for use in cosmetics in the present practices of use and concentration when formulated to avoid irritation. Aluminum calcium sodium silicate, aluminum iron silicates, magnesium aluminometasilicate (previously known as alumina magnesium metasilicate) and sodium potassium aluminum silicate were determined to be safe as cosmetic ingredients in the practices of use and concentrations.

In 2019, an amended safety assessment of synthetically manufactured, amorphous silica and hydrated silica concluded that both ingredients are safe in the present practices of use and concentration when formulated to be non-irritating.

In 2022, the Expert Panel concluded the following 24 silicate ingredients are safe in cosmetics in the present practices of use and concentration when formulated to be non-irritating, with the exception that the available data are insufficient to make a determination of safety for the use of naturally-sourced (i.e., mined) silicate ingredients in products that may be incidentally inhaled.

 

Aluminum Calcium Sodium Silicate Magnesium Silicate
Aluminum Iron Calcium Magnesium Germanium Silicates* Magnesium Trisilicate*
Aluminum Iron Calcium Magnesium Zirconium Silicates* Potassium Silicate
Aluminum Iron Silicates* Pyrophyllite*
Aluminum Silicate Sodium Magnesium Aluminum Silicate*
Ammonium Silver Zinc Aluminum Silicate Sodium Magnesium Silicate
Calcium Magnesium Silicate* Sodium Metasilicate
Calcium Silicate Sodium Potassium Aluminum Silicate
Lithium Magnesium Silicate Sodium Silicate
Lithium Magnesium Sodium Silicate Sodium Silver Aluminum Silicate*
Magnesium Aluminometasilicate Zinc Silicate*
Magnesium Aluminum Silicate Zirconium Silicate*

*No reported uses.

In the cosmetic regulations in the European Union, zirconium and its compounds (including zirconium silicate) are listed in Annex II, entry 391 and are substances prohibited in cosmetic products. The remaining silicate-related ingredients reviewed by the Expert Panel in 2022 are not restricted from use in any way under the rules governing cosmetic products in the European Union.

Resources

Food Ingredients and Packaging
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Food Contact Substances
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Substances Generally Recognized As Safe (GRAS)
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Search Title 21 of the FDA Code of Federal Regulations
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Synthetically Manufactured Amorphous Silica and Amorphous Silicates

What Is It?

Silica and hydrated silica are inorganic oxides of silicon. These ingredients are solids that can be derived from naturally occurring minerals. However, as used in cosmetics and personal care products, these ingredients are more commonly prepared synthetically. Salts of silica are called silicates, which can be derived from minerals or synthetically made.

The silica used in cosmetics and personal care products is called amorphous silica, which means the silica has an irregular pattern to the three-dimensional arrangement of atoms with no definite form. Hydrated silica has additional water atoms bound to silica. In contrast, crystalline silica, which is not used in cosmetics and personal care products, has a very different safety profile from synthetically prepared amorphous silica.

Why Is It Used?

Amorphous silica, hydrated silica and other amorphous, synthetically manufactured silicates are used in a wide range of cosmetics and personal care products, including bath products, eye makeup, hair care products, makeup, nail care products, oral hygiene products and skin care products.

Silica, hydrated silica and most of the other amorphous, synthetically-manufactured silicates function as abrasives, absorbents, anti-caking agents, bulking agents, and/or opacifying agents  in cosmetics and personal care products. Some silicate salts, such as calcium magnesium silicate, may also be used as deodorant agents.

Scientific Facts

Silica is a naturally occurring compound composed of silicon and oxygen. The amorphous, synthetically manufactured form used in cosmetics and personal care products may also be referred to as amorphous silicon oxide hydrate, silicic anhydride, silicon dioxide and silicon dioxide, fumed. Hydrated silica may also be referred to as hydrosilicic acid, precipitated silica, silica gel, silica hydrate, silicic acid, silicic acid hydrate, silicon dioxide hydrate, synthetic amorphous silicon dioxide and colloidal silica.