Ingredient review
Quaternium-18/Benzalkonium Bentonite
INCI: QUATERNIUM-18/BENZALKONIUM BENTONITE
A modified clay that helps control oil and improve product texture, generally safe for most skin types.
In plain English
This ingredient is a specially treated clay that helps thicken products and absorb excess oil. It's often used in foundations and powders to give a smooth, matte finish. The clay is modified with quaternary compounds to make it mix better with oils and other ingredients in your skincare or makeup.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Quaternium-18/Benzalkonium Bentonite is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Quaternium-18/Benzalkonium Bentonite.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A bentonite clay that has been chemically modified with quaternium-18 and benzalkonium chloride to improve its ability to thicken and absorb oil in cosmetic formulations.
How it works
It swells and forms a gel-like network in the product, which helps control viscosity and gives a smooth, spreadable texture. It also absorbs sebum and excess moisture, helping to mattify the skin and reduce shine.
Pros
Oil control
Effectively absorbs excess sebum, helping to reduce shine and keep makeup in place longer.
Texture improvement
Gives products a smooth, creamy feel that spreads easily and evenly on the skin.
Cons and cautions
Potential dryness
May strip natural oils from very dry skin, leading to tightness or flakiness.
Heavy feel
In high concentrations, it can feel thick or cakey on the skin, especially in powders.
Best for
- People with oily or combination skin
- Those looking for a matte finish in makeup or skincare
Use caution if
- People with very dry or dehydrated skin
- Those with sensitive skin who react to modified clays
Usage tips
Safety summary
Generally considered safe for topical use in cosmetics. Low irritation and comedogenic risk, but may be drying for some skin types. Avoid inhalation of loose powder forms.
Research notes
Limited direct studies on this specific modified clay, but bentonite clays are well-studied for their absorbent and thickening properties. The quaternary modifications are common and considered safe at low concentrations.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and other major markets with no known restrictions at typical concentrations.
- Common uses
- Foundations, Powders, Masks, Creams
- Environmental note
- Bentonite is a natural clay, but the chemical modification process may have environmental impacts. It is not biodegradable in its modified form.
Good to know
- This ingredient is often found in mattifying primers and oil-control powders.
- It is not water-soluble, so it works best in oil-based or emulsion formulas.
Common questions
What is Quaternium-18/Benzalkonium Bentonite in beauty products?
This ingredient is a specially treated clay that helps thicken products and absorb excess oil. It's often used in foundations and powders to give a smooth, matte finish. The clay is modified with quaternary compounds to make it mix better with oils and other ingredients in your skincare or makeup.
What does Quaternium-18/Benzalkonium Bentonite do in a beauty product?
It swells and forms a gel-like network in the product, which helps control viscosity and gives a smooth, spreadable texture. It also absorbs sebum and excess moisture, helping to mattify the skin and reduce shine.
Is Quaternium-18/Benzalkonium Bentonite safe for most people?
Generally considered safe for topical use in cosmetics. Low irritation and comedogenic risk, but may be drying for some skin types. Avoid inhalation of loose powder forms.
Who should be careful with Quaternium-18/Benzalkonium Bentonite?
People with very dry or dehydrated skin Those with sensitive skin who react to modified clays
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.