Alumina/Silica Treated Titanium Dioxide — INCI reference

What it is

Alumina/Silica Treated Titanium Dioxide consists of titanium dioxide (TiO2) particles whose surfaces have been coated with thin layers of aluminium oxide (alumina) and silicon dioxide (silica). The coatings are deposited by hydrolysis of aluminium salts or silicates in aqueous TiO2 dispersions under controlled pH conditions. These inorganic shells serve several purposes: they reduce the photocatalytic reactivity of bare TiO2, which can otherwise degrade organic co-ingredients; they improve dispersibility and stability in cosmetic matrices; and they allow further hydrophobic surface treatments. The ingredient functions primarily as a white colorant and opacifier in color cosmetics such as foundations, powders, and eyeshadows, imparting coverage and brightness. It also provides incidental UV absorption.

Safety & warnings

Considered safe for dermal use; skin absorption is minimal due to particle size. The Scientific Committee on Consumer Safety (SCCS) found no carcinogenic risk via the skin route. The primary safety concern is inhalation: TiO2 is classified as a suspected carcinogen (Category 2 CMR) by inhalation in the EU, so use in spray or powder formats that could be inhaled is restricted or prohibited. Products containing nano-form material must be labeled with '(nano)' in the EU. Not considered a sensitizer or comedogen on intact skin. Some studies note a knowledge gap regarding penetration through damaged or repeatedly treated skin.

Origin & sourcing

Produced synthetically from titanium ore (rutile or ilmenite) via the sulfate or chloride process to obtain TiO2, followed by surface treatment in aqueous slurry with aluminium sulfate or sodium aluminate (for the alumina layer) and sodium silicate (for the silica layer), then filtered, washed, dried, and milled to a fine white powder.

History

Alumina and silica surface treatments for TiO2 pigments were developed in industrial paint applications from the 1940s–1960s to improve durability and dispersibility. Their adoption in cosmetics followed as mineral pigment technology matured. EU Cosmetics Regulation (EC) 1223/2009 Annex VI explicitly lists alumina and silica among approved coatings for nano TiO2 UV filters; Commission Regulation (EU) 2019/1857 updated permitted coating combinations.

Questions everyone asks

Why is titanium dioxide coated with alumina and silica?

The coatings reduce the photocatalytic activity of bare TiO2, which can break down organic ingredients under UV light. They also improve how well the particles disperse in cosmetic formulas and can serve as a base for additional hydrophobic surface treatments.

Is this the same as the TiO2 UV filter used in sunscreens?

Related but distinct. Sunscreen-grade TiO2 is often nano-sized (under 100 nm) and is listed separately as Titanium Dioxide [nano]. Alumina/Silica Treated Titanium Dioxide typically refers to conventional pigment-grade material used primarily for white coverage and opacity in color cosmetics rather t

Is it safe for sensitive skin?

Generally yes. Titanium dioxide is regarded as one of the gentler cosmetic minerals with very low sensitization potential. The alumina and silica coatings further stabilize the particle, and dermal absorption is negligible for pigment-grade sizes.

Are there restrictions on which products can contain it?

EU regulations restrict TiO2, especially in nano form, from spray and inhalable powder applications due to lung inhalation risks. It is permitted in leave-on and rinse-off skin products. The EU maximum concentration is 25% in ready-to-use preparations applied to the skin.