Silica is a common ingredient in cosmetic products, valued for its mattifying, texturising and absorbent properties. But where does it actually come from, and how is it processed before being incorporated into our creams or powders? Discover how it is extracted.
How is the silica used in cosmetics extracted?
Summary
Published on July 31, 2025, by Lilia, Scientific Editor — 4 min of reading
Themes:
The natural origin of silica: mineral extractions.
The silica used in cosmetics can be of natural mineral origin. It is particularly extracted from silicon dioxide-rich rocks, such as quartz, siliceous sand or diatomite. The latter is a sedimentary rock composed of the microscopic fossils of single-celled algae known as diatoms. These deposits are mechanically milled and then purified to remove mineral and organic impurities. The resulting product is generally a fine porous powder, called natural amorphous silica. Its disordered structure makes it safer for cosmetic use than the silica crystalline, potentially toxic if inhaled in respirable particulate form. This natural form is primarily used for its absorbing and mattifying.
Precipitated silica: a controlled production.
The most commonly used form in cosmetic formulations is the precipitated silica, also known as synthetic amorphous silica. It is obtained through a chemical reaction between sodium silicate and a strong acid, such as sulfuric or hydrochloric acid. This reaction, carried out in an aqueous medium under stirring, induces the precipitation of silica particles in the form of a gel or powder. The synthesis conditions (temperature, pH, reaction time) directly influence the particle size, their porosity and morphology, yielding grades tailored for various uses: thickeners, mattifying agents, opacifiers or texture enhancers. This form is highly purified and contains no crystalline silica. It is approved by regulatory bodies such as EFSA and the SCCS for non-inhalation cosmetic applications.
Colloidal silica: nanoparticles in suspension.
The silica can also be obtained in colloidal form, that is dispersed in water on a nanometre scale. This form is produced by the controlled polymerisation of silicic acid in an aqueous medium. The process generates a stable suspension of spherical nanoparticles of amorphous silica, generally between 5 and 100 nanometres in diameter. This colloidal form is primarily used as a texture-stabilising agent or to enhance the film-forming effect of certain gels or serums. However, its use in cosmetics is regulated due to concerns regarding nanomaterials, particularly when they may penetrate the skin barrier or be inhaled. In topical applications, these forms are considered safe provided they are not used in aerosols or inhalable loose powders.
Strictly regulated safety in silica extraction.
The different forms of silica used in cosmetics are regulated and evaluated by European bodies. The Scientific Committee on Consumer Safety (SCCS) confirmed in 2015 that precipitated, hydrated or colloidal amorphous silica poses no health risk when used under the recommended conditions of use. In contrast, the crystalline silica naturally present in sand or quartz is prohibited in cosmetic products due to its potential toxicity when inhaled.
Sources
Scientific Committee on Consumer Safety (SCCS). Opinion on Silica, Hydrated Silica, and Silica Surface Modified with Alkyl Silylates (nano form). Public Health (2015).
KHOTSENG L. & al. Extraction and Synthesis of Silicon Nanoparticles (SiNPs) from Sugarcane Bagasse Ash: A Mini-Review. Applied Sciences (2022).
KHOTSENG L. & al. Green synthesis of silica and silicon from agricultural residue sugarcane bagasse ash – a mini review. RSC Advances (2023).
HOSSEN F. & al. Production and Characterization of Silica from Rice Husk: An Updated Review. Asian Journal of Chemical Sciences (2024).
