What Is Quaternium-90 Bentonite?
Quaternium-90 Bentonite is a specialty form of bentonite clay that has been chemically linked with a conditioning agent known as Quaternium-90. Bentonite itself is a naturally occurring clay mined from volcanic ash deposits while Quaternium-90 is a quaternary ammonium compound prized for its ability to bond with both water and oil. When the two are reacted together the clay particles gain a permanent positive charge, which improves how they disperse in water-based formulas and how they interact with skin and hair.
The idea of pairing clays with quaternary compounds emerged in the late 20th century as chemists looked for ways to make thick, stable yet smooth products without heavy waxes or gums. By treating bentonite with Quaternium-90 they created a clay that swells quickly, stays suspended and feels silky rather than gritty. Production involves hydrating purified bentonite, introducing the Quaternium-90 solution under controlled heat and pH then drying and milling the final reacted powder.
You will most often find Quaternium-90 Bentonite in rinse-off masks, creamy cleansers, scrubs, styling pomades, sunscreens, tinted moisturizers and other products that need a reliable thickener that does not feel heavy or dusty.
Quaternium-90 Bentonite’s Cosmetic Benefits/Uses
In formulations Quaternium-90 Bentonite is valued for a single key role
Viscosity controlling: The ingredient swells and forms a soft gel network that thickens liquids, helping creams stay rich and uniform and keeping pigments or exfoliating particles from settling. Because its structure is clay-based the thickening effect feels light and non-greasy, allowing brands to create products that spread evenly yet do not drip or separate during storage.
Who Can Use Quaternium-90 Bentonite
Because Quaternium-90 Bentonite is a mineral-based thickener that stays mostly on the surface, it suits most skin types including normal, oily and combination skin that appreciate its light non-greasy feel. Dry or very sensitive skin can also tolerate it in well-balanced formulas, although if a product relies heavily on clay absorption it may leave these skins feeling a bit tight.
The ingredient is derived from natural clay and a lab-made conditioning agent, neither of which come from animals, so products using Quaternium-90 Bentonite are normally appropriate for vegans and vegetarians as long as the rest of the ingredient list also meets those standards.
No specific warnings exist for pregnant or breastfeeding women. The compound is used topically, is not readily absorbed and has no known hormone-related activity. This is not medical advice and anyone who is pregnant or nursing should run any skincare product past a doctor just to be on the safe side.
Quaternium-90 Bentonite does not increase photosensitivity. Standard daytime sun protection practices remain sufficient.
Potential Side Effects/Adverse Reactions
Reactions to topical Quaternium-90 Bentonite can vary from person to person. The points below outline potential effects but most users will not experience them when the ingredient is properly formulated and used as intended.
- Mild skin dryness
- Temporary tightness or flaking in very dry skin
- Rare cases of contact irritation such as redness or itching
- Allergic response to other formula components that may be mistaken for a reaction to the clay
If any persistent irritation or discomfort occurs discontinue use and consult a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Quaternium-90 Bentonite sits low on the scale because its clay structure is porous and non-occlusive, so it does not trap oil or create a heavy film that could block pores. The quaternary treatment helps it disperse evenly rather than clump on the skin which further lowers the chance of congestion.
Suitable for acne-prone or breakout-prone skin in most cases, provided the rest of the formula is also low in pore-clogging ingredients.
As with any clay-based thickener, using it in very heavy concentrations or in products that are not rinsed off could, in rare instances, accentuate dryness which might prompt the skin to overproduce oil, indirectly encouraging blemishes. Formulators usually balance it with humectants and light emollients to avoid this.
Summary
Quaternium-90 Bentonite is mainly a viscosity controller. By swelling in water and forming a smooth gel network it thickens lotions, masks and cleansers, keeps pigments suspended and gives formulas a light cushiony feel without greasiness.
It is a niche ingredient rather than a mainstream superstar, but brands that want a silky clay thickener with easy processing turn to it regularly, especially in modern cream masks and hybrid skincare-makeup products.
Safety data show it is generally well tolerated, non-sensitizing and low on the comedogenic scale. Still, everyone’s skin is unique so it is smart to patch test any new product that contains Quaternium-90 Bentonite before committing to full-face use.