Ingredient review
Cetyldimethylsiloxy Trimethylsiloxysilicate
INCI: Cetyldimethylsiloxy Trimethylsiloxysilicate
A gentle silicone that helps products glide on smoothly and resist water, but may not suit those avoiding silicones entirely.
In plain English
This is a type of silicone that forms a thin, breathable film on your skin or hair. It helps lotions and creams spread easily, makes makeup last longer, and can add a silky, non-greasy feel. It's also used in sunscreens to help them stay effective when you sweat or swim. Think of it as a lightweight, invisible shield that doesn't clog pores.
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
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Cetyldimethylsiloxy Trimethylsiloxysilicate 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 Cetyldimethylsiloxy Trimethylsiloxysilicate.
- 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 synthetic silicone polymer (a type of siloxane) with a long-chain alkyl group (cetyl) attached. It is designed to be highly compatible with skin and hair, providing a smooth, non-sticky finish.
How it works
When applied, the molecules align to form a thin, flexible film on the surface. This film reduces water loss from the skin (helping with moisture), improves the feel of the product, and can help other ingredients stay in place longer. It also helps sunscreens resist wash-off from water or sweat.
Pros
Smooth, silky feel
Leaves skin and hair feeling soft and velvety without being greasy or heavy.
Boosts water resistance
Helps sunscreens and makeup stay effective longer when you sweat or get wet.
Cons and cautions
Not biodegradable
As a synthetic silicone, it does not break down easily in the environment, which may be a concern for eco-conscious users.
Can require double cleansing
Its film-forming nature means a single gentle cleanser may not remove it completely, so you might need an oil-based cleanser first.
Best for
- People looking for a smooth, silky finish in moisturizers or primers
- Those who want extra water resistance in their sunscreen or long-wear makeup
Use caution if
- Anyone strictly avoiding all silicones for personal or environmental reasons
Usage tips
Safety summary
Cetyldimethylsiloxy Trimethylsiloxysilicate is considered safe for use in cosmetics at typical concentrations. It has a low irritation and comedogenic risk, making it suitable for most skin types, including sensitive skin.
Research notes
Safety assessments by cosmetic ingredient review panels (e.g., CIR) have concluded that similar silicone polymers are safe as used. Specific studies on this exact ingredient are limited, but its chemical class is well-established as low-risk.
Common label clues
- Typical concentration
- 1% to 10%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU, and many other regions. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Moisturizers, Sunscreens, Primers, Hair serums, Color cosmetics
- Environmental note
- Silicones like this one are not biodegradable and can accumulate in the environment. Some manufacturers are working on more eco-friendly alternatives.
Good to know
- This ingredient is often found in 'water-resistant' or 'long-wear' formulas.
- It is considered non-comedogenic and generally safe for sensitive skin.
Common questions
What is Cetyldimethylsiloxy Trimethylsiloxysilicate in beauty products?
This is a type of silicone that forms a thin, breathable film on your skin or hair. It helps lotions and creams spread easily, makes makeup last longer, and can add a silky, non-greasy feel. It's also used in sunscreens to help them stay effective when you sweat or swim. Think of it as a lightweight, invisible shield that doesn't clog pores.
What does Cetyldimethylsiloxy Trimethylsiloxysilicate do in a beauty product?
When applied, the molecules align to form a thin, flexible film on the surface. This film reduces water loss from the skin (helping with moisture), improves the feel of the product, and can help other ingredients stay in place longer. It also helps sunscreens resist wash-off from water or sweat.
Is Cetyldimethylsiloxy Trimethylsiloxysilicate safe for most people?
Cetyldimethylsiloxy Trimethylsiloxysilicate is considered safe for use in cosmetics at typical concentrations. It has a low irritation and comedogenic risk, making it suitable for most skin types, including sensitive skin.
Who should be careful with Cetyldimethylsiloxy Trimethylsiloxysilicate?
Anyone strictly avoiding all silicones for personal or environmental reasons
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.