A specific user guide for silica?

How to use silica?

Silica, a multifaceted mineral ingredient, is widely employed in cosmetics for its absorbent, mattifying and texturising properties. This naturally raises the question of its mode of use. Discover more on this topic in this article.

Published on September 10, 2025, by Lilia, Scientific Editor — 6 min of reading

Silica: an interesting mineral ingredient.

The silica, or silicon dioxide (SiO₂), is a mineral-derived ingredient commonly used in cosmetics. It is extracted from natural raw materials such as quartz, sand or diatomite. In cosmetic applications, only amorphous forms (precipitated or colloidal) are employed, as these are deemed safe, unlike crystalline silica, which is prohibited due to its toxicity by inhalation.

Amorphous silica is obtained by chemical precipitation from sodium silicates and a strong acid. It is recognised for its absorbing and mattifying properties. It can help regulate sebum, reduce shine, and optically smooth pores and fine lines. It is also used as a thickening or mild abrasive agent in toothpastes. Its versatility and good tolerability make it an interesting ingredient in cosmetic products.

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Silica in cosmetics: how is it used?

Silica, particularly in its amorphous (non-crystalline) form, is incorporated into a wide range of skin care, sun care, hair care, make-up and exfoliants. In facial treatments and sunscreens, it acts as a thickening, stabilising and absorbent agent: it improves the texture of formulations, reduces greasiness and enhances the stability of UV filters, especially in mineral sunscreens. Recent studies on plant-derived silicas (from sugarcane bagasse) have demonstrated good stability and a potential effect on pro-collagen synthesis.

In make-up, silica is prized for its strong absorptive power: it captures excess sebum and reduces shine, offering a long-lasting matte finish. Its microporous structure also provides a "soft-focus" effect, optically blurring pores and imperfections for a more even complexion.

In hair care, it is used in dry shampoos and texturising sprays to absorb sebum at the roots without leaving any visible residue, while adding volume and texture. It also offers an eco-friendly alternative to microplastics through its biodegradability. Finally, in mechanical exfoliants, silica is employed as particles with controlled size and hardness, enabling gentle, effective exfoliation that is suitable for sensitive skin, while also being kind to the environment.

And regarding the safety and regulation of silica used in cosmetics?

Although silica is used in cosmetics in certain formulations, guidelines are provided regarding safety and use of the silica and the authorised forms. Here are the main conditions of use recommended by the SCCS (Scientific Committee on Consumer Safety) regarding amorphous silica in cosmetics, drawn from Opinion SCCS/1545/15 (2015):

Permitted forms
Precipitated, hydrated or colloidal amorphous silica, non-crystalline.
Recommended maximum usage concentrations
No strict overall limit is established, but silica is typically employed at concentrations ranging up to 15% in cosmetic formulations, depending on the product type.
Particle size and nanomaterials
Silica can be used in the form of nanoparticles, but these must be stable, non-toxic and must not penetrate the skin. The SCCS emphasises that the nanoparticulate form must be assessed to ensure no dermal penetration and no systemic toxicity.
Inhalation
Amorphous silica is prohibited in products likely to be inhaled, particularly in loose powders, owing to the potential respiratory hazard associated with inhalation of fine particles.
Topical use
Amorphous silica is considered safe for skin application, including in products for mucous membranes, provided the particles are not inhaled.