What does kaolin clay do for your skin?
Kaolin is a soft white clay, also known as china clay, that absorbs oil from the surface of the skin. It's widely used in face masks, and in a bath it disperses into the water so it reaches the whole body at once.
Quick answer
- Kaolin is a soft white clay, also called china clay, made mostly of the mineral kaolinite.
- On the skin it absorbs oil from the surface, so skin can feel cleaner and less oily once the clay is rinsed away.
- In a bath it disperses into the water and turns it soft and milky, reaching shoulders, back and legs at once.
- It works only on the surface of the skin: kaolin is a cosmetic ingredient, not a medicine.
What is kaolin clay?
Kaolin is a white clay made mostly of kaolinite, a hydrated aluminium silicate mineral. Its particles are extremely fine and flat, a little like tiny plates, which is why it feels so soft and smooth. In the UK it is better known as china clay, and it is mined from the granites of south-west England, mainly around St Austell in Cornwall and on the edge of Dartmoor in Devon.
It formed over geological time, as the feldspar in granite was slowly broken down by hot fluids underground and by weathering at the surface.
Where does the name kaolin come from?
The name comes from Gaoling (Kaoling), a village in China whose white clay was used to make porcelain. Kaolin still gives porcelain and bone china their whiteness, and most of the kaolin sold from the UK goes into paper and ceramics rather than skincare.
In skincare you'll usually see it listed as kaolin, or sold as white clay.
What does kaolin clay do for your skin?
Kaolin absorbs oil. Its fine particles take up oil sitting on the surface of the skin, and when the clay is rinsed away, some of that oil goes with it. That is the idea behind a clay mask, and it's why skin can feel cleaner and less oily afterwards.
In cosmetic ingredient databases, kaolin is listed for several jobs: absorbing oil, bulking out a formula, stopping powders from caking, adding colour and making a product opaque. That range is why it turns up in so many face masks.
Kaolin is a cosmetic ingredient and works only on the surface of the skin. If you have a skin condition, check with a doctor before trying something new.
Is kaolin clay good for sensitive skin?
Kaolin is soft, non-abrasive and chemically inert, and the Cosmetic Ingredient Review expert panel, which assesses the safety of cosmetic ingredients in the US, has concluded that kaolin and related clays are safe as used in cosmetics. That is a statement about the ingredient, not a promise for every skin.
If your skin is sensitive, patch-test anything new on a small area first, start with a lighter soak (fewer clay blocks, a shorter bath) and moisturise afterwards.
How is kaolin different from other clays?
Cosmetic clays are not all alike. Kaolin stands out in three ways:
- It's white and fine. Its colour and small, flat particles are what make it valued in porcelain, paper and cosmetics alike.
- It doesn't swell. Kaolin stays fine and soft in water, and it is far less chemically active than clays such as bentonite.
- It's soft, not gritty. Refined kaolin has the coarser grains removed, so it feels smooth rather than scratchy.
What's the difference between a kaolin face mask and a kaolin bath?
In a face mask, kaolin is mixed into a paste, left on for about 10 minutes and rinsed off. In a bath, the same clay is dispersed through the water, so it works on shoulders, back, arms and legs at once. It's a full-body version of a clay mask, far more diluted, and the water turns soft and milky.
How do you use kaolin clay in the bath?
- Run the bath warm, not hot. Very hot water can leave skin feeling dry.
- Add the clay once the bath is full so it disperses evenly. The water will turn soft and milky.
- Soak for 15 to 20 minutes. Our guide to how long to soak in the bath covers timing and temperature.
- Rinse off with clean water and pat dry. Follow with a moisturiser while skin is still slightly damp, especially if it tends to feel dry.
Kaolin sits well alongside oat. For a softer, creamier soak, see our guide to the oat milk bath.
How often can you have a kaolin bath?
Once or twice a week suits most people. Clay absorbs oil, so if your skin starts to feel dry or tight, space the baths out and moisturise after each one.
Kaolin in SLATE
Every SLATE block has kaolin clay in its base formula, at 3%. The CLAY block raises it to 8%, so the more CLAY blocks you add to your Grid™, the more of a clay soak your bath becomes. Each block is about 22 g, and every block also contains 10% Epsom salt and sweet almond oil, a tree nut.
The System explains how texture blocks such as CLAY sit alongside scent blocks in a Grid™.
A Grid™ for a clay soak
9 CLAY · Kaolin clay · Lifts surface oil
9 OAT · Colloidal oat · Calm and soften
9 CALM · Lavender and chamomile · Quiet the noise
Build this Grid™ →
Common questions
Is kaolin clay the same as white clay?
Yes. Kaolin is often sold as white clay, and in the UK it is also called china clay.
Can kaolin clay go in a bath?
Yes. It disperses into the water and turns it softly milky, so it reaches the whole body rather than just the face.
Does kaolin clay dry out your skin?
Kaolin absorbs oil, so skin can feel drier or tighter afterwards, particularly after a long or hot bath. Keep the water warm rather than hot, soak for 15 to 20 minutes and moisturise while skin is still damp.
Is kaolin safe to use in cosmetics?
The Cosmetic Ingredient Review expert panel concluded that kaolin and related clays are safe as used in cosmetics. Patch-test any new product, and avoid breathing in loose clay powder if you mix your own.
What does CI 77004 mean on an ingredient list?
CI 77004 is another name for kaolin, taken from the Colour Index, the naming system used for ingredients that add colour.
How often can I use a kaolin bath?
Once or twice a week is plenty for most people.
Sources
- Mineral planning factsheet: kaolin, British Geological Survey, 2009
- Final report on the safety assessment of aluminum silicate, calcium silicate … kaolin … and zeolite, Cosmetic Ingredient Review Expert Panel, International Journal of Toxicology, 2003
- Kaolin: INCI ingredient entry, CosmileEurope (Cosmetics Europe)
SLATE products are cosmetics for external use only. If you have a skin condition, are pregnant, or have any concerns, check with your doctor before use. Patch-test any new product. Keep out of reach of children. Contains essential oils; see each block's ingredient list for allergens. Every block contains sweet almond oil (tree nut).
SLATE is a soak for the body and mind: small-batch bath blocks of cosmetic-grade ingredients, made in the UK. Build your Grid™
