Ingredient review
Trimethylsiloxysilicate/Dimethiconol Crosspolymer
INCI: TRIMETHYLSILOXYSILICATE/DIMETHICONOL CROSSPOLYMER
A silicone film-former that helps makeup last longer and protects skin from moisture loss without feeling heavy.
In plain English
This is a type of silicone that forms a thin, flexible, invisible film on your skin or hair. It helps makeup stay put, makes skin feel silky, and can lock in moisture by reducing water evaporation. Think of it like a breathable raincoat for your skin — it protects without suffocating.
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
Trimethylsiloxysilicate/Dimethiconol Crosspolymer 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 Trimethylsiloxysilicate/Dimethiconol Crosspolymer.
- 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 crosslinked silicone polymer made by combining trimethylsiloxysilicate (a film-forming silicone resin) with dimethiconol (a silicone fluid). The crosslinking creates a flexible, durable network that spreads easily and dries down to a smooth, non-sticky finish.
How it works
When applied, the polymer forms a continuous, flexible film over the skin or hair. This film helps other ingredients (like pigments or UV filters) adhere evenly, resists water and sweat, and reduces transepidermal water loss (TEWL — the amount of water that evaporates from your skin). It also imparts a silky, velvety feel without greasiness.
Pros
Long-lasting wear
Helps foundation and sunscreen stay in place for hours, even in humidity or water exposure.
Smooth, non-greasy feel
Leaves a silky, velvety finish on skin and hair without the sticky or oily residue common with other film-formers.
Cons and cautions
Requires thorough removal
Because it forms a water-resistant film, it won't wash off with plain water or gentle cleansers. You'll likely need an oil-based cleanser or double cleansing to avoid buildup.
Environmental persistence
As a synthetic silicone, it is not biodegradable and can accumulate in waterways, raising concerns for aquatic ecosystems.
Best for
- People who want long-lasting, transfer-resistant makeup
- Those with normal to dry skin looking for a gentle occlusive layer
Use caution if
- Anyone who prefers silicone-free or fully biodegradable formulations
Usage tips
Safety summary
Trimethylsiloxysilicate/Dimethiconol Crosspolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. The main concern is environmental persistence rather than human toxicity.
Research notes
Safety assessments by the Cosmetic Ingredient Review (CIR) panel have found silicone film-formers like this to be safe when used as intended. Most evidence comes from industry safety data and regulatory reviews rather than independent clinical trials.
Common label clues
- Typical concentration
- 1% to 10%
- Regulatory status
- Approved for use in cosmetics globally, including by the U.S. FDA and EU CosIng database. No specific concentration restrictions.
- Common uses
- Long-wear foundations, Sunscreens, Waterproof mascaras, Hair serums, Primers
- Environmental note
- Silicones like this one are not readily biodegradable. Some manufacturers are working on more eco-friendly alternatives, but recycling and disposal remain challenges.
Good to know
- This ingredient is often used in 'transfer-proof' or '24-hour wear' makeup formulas.
- It is considered non-comedogenic for most skin types, but everyone's skin is different — patch test if you're prone to breakouts.
Common questions
What is Trimethylsiloxysilicate/Dimethiconol Crosspolymer in beauty products?
This is a type of silicone that forms a thin, flexible, invisible film on your skin or hair. It helps makeup stay put, makes skin feel silky, and can lock in moisture by reducing water evaporation. Think of it like a breathable raincoat for your skin — it protects without suffocating.
What does Trimethylsiloxysilicate/Dimethiconol Crosspolymer do in a beauty product?
When applied, the polymer forms a continuous, flexible film over the skin or hair. This film helps other ingredients (like pigments or UV filters) adhere evenly, resists water and sweat, and reduces transepidermal water loss (TEWL — the amount of water that evaporates from your skin). It also imparts a silky, velvety feel without greasiness.
Is Trimethylsiloxysilicate/Dimethiconol Crosspolymer safe for most people?
Trimethylsiloxysilicate/Dimethiconol Crosspolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. The main concern is environmental persistence rather than human toxicity.
Who should be careful with Trimethylsiloxysilicate/Dimethiconol Crosspolymer?
Anyone who prefers silicone-free or fully biodegradable formulations
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.