Why we use kaolin and rhassoul, not bentonite

If you’ve looked at clarifying soap ingredients, you’ve probably seen bentonite clay come up. It’s everywhere in the “detox skincare” category, marketed as the strongest clay, the one that “draws out” the most.

We use kaolin and rhassoul instead. Here’s why that’s the right call.

What clays do

All clays work through ion exchange. Clay particles carry a slight negative charge. Sebum, sweat residue, and environmental grime tend to carry a positive charge. Opposites attract, the clay binds the debris, and the whole thing rinses off. That’s the mechanism. None of it is magic.The difference between clay types is in how aggressively they do this and what they leave behind.

Bentonite is too aggressive for a rinse-off product

Bentonite has a very high swelling capacity. It expands significantly when it hits water, which gives it strong drawing power. In a face mask that you wear for ten minutes and rinse, that can be useful. In a rinse-off bar soap, it’s too much. The contact time is shorter, the skin is wet and more permeable, and bentonite at that level of absorption can strip moisture alongside the grime. For a lot of skin types, especially anything on the sensitive or dry end, that means tightness and irritation.

Kaolin and rhassoul do the job without the overreach

Kaolin is a soft, white clay with a much milder draw. It absorbs excess oil without stripping the skin’s natural moisture. It works well across skin types, including sensitive. Rhassoul is a rarer Moroccan clay, higher in silica and magnesium, with a slightly stronger action than kaolin but significantly gentler than bentonite. Together, they handle oil and debris without taking everything with them. Marbled Charcoal uses both, alongside activated charcoal for additional surface-level absorption. The result is a thorough clean that doesn’t punish your skin for having it.

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