Kaolin

What it is

Kaolin is a naturally occurring hydrated aluminium silicate, mined from weathered granite deposits and then washed, dried and milled. Chemically it is a non-swelling clay, so it absorbs oil and water without turning into a stiff gel the way bentonite does. Formulators use it in wash-off masks, cleansing powders and pressed powders because it gives a smooth, matte texture and mops up sebum. It is inert, does not dissolve in water and stays on the skin surface.

What it does well

• Absorbs surface oil and sebum

  Kaolin's high surface area lets it take up sebum and water, which is why a kaolin mask leaves skin feeling matte. The effect is physical and temporary rather than a lasting change in oil production.

  Moderate evidence

• Gentler than swelling clays like bentonite

  Because kaolin does not swell or shrink strongly as it dries, it tends to pull less on the skin than bentonite or rhassoul. The 2026 Cosmetic Ingredient Review panel concluded kaolin is safe as currently used, without the inhalation caveat it applied to the other clays it reviewed.

  Moderate evidence

Worth knowing

• Can over-dry skin if left on too long

  Leaving a clay mask on until it cracks removes more water than oil and can leave the skin barrier feeling tight. Rinsing while the mask is still slightly damp avoids this.

  Matters most toPeople with dry, dehydrated or eczema-prone skin.

• Naturally contains trace heavy metals

  All mined clays carry small amounts of lead, arsenic and cadmium from the parent rock; published surveys of natural kaolinitic clays report lead in the tens of parts per million and arsenic up to about 15 ppm. Work on topical clay gels found that only a tiny fraction is actually mobile - arsenic and cadmium released at about 0.1 and 0.2 micrograms per 100 g of gel - and concluded such products can be applied to skin without meaningful intoxication risk.

  Matters most toGenerally no one at normal wash-off use; relevant mainly to people eating clay, which some traditional practices involve.

• Loose powder should not be inhaled

  Mixing dry clay powder raises a fine dust. Repeated inhalation of mineral dust is an occupational concern, not a consumer one, but it is sensible to avoid breathing in the powder while mixing a DIY mask.

  Matters most toAnyone mixing loose clay powder at home, and children.

Where the EU stands

Sources (3)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Amended Safety Assessment of Naturally-Sourced Clays as Used in Cosmetics

   International Journal of Toxicology (Cosmetic Ingredient Review Expert Panel) · 2026 · doi:10.1177/10915818261455355

   The expert panel concluded kaolin is safe in cosmetics as currently used, and that the other clays reviewed are safe except where data on incidental inhalation are insufficient.

2. [2]
   Safety of Nanoclay/Spring Water Hydrogels: Assessment and Mobility of Hazardous Elements

   Pharmaceutics · 2020 · doi:10.3390/pharmaceutics12080764

   Arsenic and cadmium present in clay-based topical gels were only mobilised in very small amounts (0.1 and 0.2 micrograms per 100 g), so the gels could be applied to skin without major intoxication risk.

3. [3]
   Genotoxicity of micro- and nano-particles of kaolin in human primary dermal keratinocytes and fibroblasts

   Genes and Environment · 2020 · doi:10.1186/s41021-020-00155-1

   Kaolin particles caused DNA damage in isolated skin cells at high doses in culture, with smaller particles more active - a cell-culture finding that has not been shown to translate to intact skin, where kaolin does not penetrate.