What Is Quaternium-90 Sepiolite?
Quaternium-90 Sepiolite is a hybrid ingredient created when quaternium-90, a positively charged conditioning agent, reacts with sepiolite, a naturally occurring clay made of magnesium silicate. The result is a fine powder that carries a gentle positive charge, which helps it interact well with the mostly negative surfaces of hair and skin. Clay minerals such as sepiolite have been valued for centuries for their ability to absorb oil and add texture, and in the late 20th century formulators began bonding them with quaternary compounds like quaternium-90 to boost stability and ease of use.
The manufacturing process is straightforward: sepiolite clay is dispersed in water, quaternium-90 is introduced, then the mixture is stirred so the cationic molecules anchor onto the clay’s surface. After filtration and drying, the modified clay is milled into a uniform powder ready for cosmetic use.
You are most likely to find Quaternium-90 Sepiolite in creams, lotions, facial masks, sunscreens, makeup foundations, hair conditioners and styling gels where it helps keep formulas smooth and pleasant to apply.
Quaternium-90 Sepiolite’s Cosmetic Benefits/Uses
In skin and hair care formulas Quaternium-90 Sepiolite offers two key technical benefits that improve both product performance and user experience:
- Emulsion stabilising: It helps keep oil and water from separating so creams and lotions stay smooth from the first pump to the last swipe
- Viscosity controlling: It thickens or suspends a formula, giving products the right body so they spread evenly without running or feeling too heavy
Who Can Use Quaternium-90 Sepiolite
Because it is largely inert and sits on the surface rather than sinking deeply into skin, Quaternium-90 Sepiolite is considered suitable for all skin types including oily, combination, normal and dry. Even sensitive skin generally tolerates it well since the modified clay has a low irritation profile. People prone to eczema or rosacea may still want to keep an eye on how their skin responds, mainly because any clay-based thickener can feel drying if used in very high amounts.
The ingredient is mineral based and made without animal-derived substances, so it meets vegan and vegetarian standards. Most suppliers also confirm that no animal testing is involved in the production process.
No specific warnings exist for pregnant or breastfeeding women. The ingredient is used at very low concentrations and sits on the surface, meaning systemic absorption is negligible. This is not medical advice and anyone who is pregnant or nursing should show the full product ingredient list to a qualified healthcare professional before use to be extra safe.
Quaternium-90 Sepiolite is not known to cause photosensitivity so you do not need special sun precautions beyond the usual daily SPF recommendation. It also has no documented interference with prescription topicals or over-the-counter actives.
Potential Side Effects/Adverse Reactions
Reactions vary from person to person. The effects listed below are only potential issues and are unlikely when the ingredient is used at normal cosmetic levels
- Mild skin dryness or tightness if the formula contains a high percentage of clay
- Temporary redness or itching in individuals who are sensitive to quaternary ammonium compounds
- Eye irritation if the raw powder or the product accidentally gets into the eyes
- Respiratory discomfort when inhaling the raw powder during manufacturing or DIY handling
If you notice persistent irritation or any unexpected reaction discontinue use and consult a healthcare professional
Comedogenic Rating
Rating: 1/5
Quaternium-90 Sepiolite is a finely milled clay coated with a conditioning agent that stays on the skin’s surface and does not melt into pores. Its oil-absorbing nature actually helps reduce excess sebum so the likelihood of it trapping debris and forming comedones is very low. The presence of the quaternary coating adds slip without contributing occlusive oils or waxes, keeping pore blockage risk minimal.
Because of this low score it is generally suitable for acne-prone or breakout-prone skin.
As with any powdered clay, very heavy use in leave-on products can create a dry film that might mix with natural skin oils and build up over time, but normal cosmetic levels rarely reach that point.
Summary
Quaternium-90 Sepiolite stabilises emulsions and controls viscosity by acting as a bridge between oil and water while adding body to the formula. The positively charged quaternium portion anchors onto the negatively charged clay, creating a network that keeps droplets suspended and thickens the product without heaviness.
It is a niche ingredient mostly seen in mid to high-end creams, masks and styling aids rather than in mass-market basics, but formulators appreciate its reliable performance and smooth skin feel.
Safety data show a low irritation profile, negligible absorption and a minimal risk of clogging pores. Still, everyone’s skin is different so doing a small patch test with any new product that contains Quaternium-90 Sepiolite is a smart step.