What it is
Disteardimonium hectorite is an organically modified form of hectorite, a smectite clay, in which the clay's surface has been treated with quaternary ammonium (stearyl-type) groups so it disperses and gels in oils rather than water. In a formula it acts as a rheology modifier, thickening the product and keeping it from being runny, and it suspends pigments and other solids so they do not settle during storage. This makes it especially useful in sunscreens and makeup, where it helps keep UV filters and color pigments evenly distributed and contributes a light, smooth feel.
Safety & warnings
Disteardimonium hectorite is a large, surface-treated clay particle that stays on the skin surface and is used as a formulation aid rather than an active ingredient, so it is generally regarded as well tolerated. Published consumer ingredient references for this material do not highlight specific irritation or sensitization concerns. As with any cosmetic ingredient, anyone with reactive skin should patch test a new product.
Origin & sourcing
It starts from hectorite, a rare, soft, lithium-rich clay mineral of the smectite group first identified near Hector, California. The naturally occurring clay is then chemically modified by exchanging its surface ions for di-stearyl quaternary ammonium groups, turning the water-loving clay into an oil-dispersible organoclay.
Questions everyone asks
What is disteardimonium hectorite made from?
It is hectorite, a natural clay mineral, that has been chemically modified with quaternary ammonium groups so it can thicken and gel oil-based formulas.
Why is it used in sunscreens?
It thickens the formula and keeps UV filters and pigments suspended so they do not settle, and it helps give a smooth feel.
Is it the same as Bentone 38?
Bentone 38 is a common trade name under which disteardimonium hectorite is sold for cosmetic use.