Ingredient review
Dimethicone/Silsesquioxane Copolymer
INCI: Dimethicone/Silsesquioxane Copolymer
A silicone polymer that helps makeup and skincare last longer by forming a flexible, breathable film that resists water and sweat.
In plain English
This is a type of silicone that creates a thin, flexible film on your skin or hair. Think of it like a very light, invisible shield that helps your makeup stay put and your sunscreen stay effective, even when you sweat or get wet. It also makes the product feel silky and smooth when you apply it.
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
Dimethicone/Silsesquioxane Copolymer 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 Dimethicone/Silsesquioxane Copolymer.
- 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 made by combining dimethicone (a common silicone oil) with silsesquioxane (a silicone resin). The result is a hybrid material that has both film-forming and water-resistant properties.
How it works
When applied, the copolymer forms a thin, even film on the skin or hair surface. This film helps other ingredients (like pigments in foundation or UV filters in sunscreen) stay in place longer. It also repels water and sweat, making the product more durable. The film is flexible, so it moves with your skin without cracking or feeling tight.
Pros
Long-lasting wear
Helps makeup and sunscreen stay put for hours, even in humid or sweaty conditions, so you don't need to reapply as often.
Smooth application
Gives products a silky, spreadable texture that glides on easily and leaves a non-greasy finish.
Cons and cautions
Can be hard to remove
Because it forms a water-resistant film, you'll likely need an oil-based cleanser or micellar water to fully wash it off, which adds a step to your routine.
May feel heavy on oily skin
For those with very oily or acne-prone skin, the film can feel a bit occlusive or contribute to a heavy sensation, though it is generally non-comedogenic.
Best for
- People who want long-lasting makeup or waterproof sunscreen
- Those with normal to dry skin looking for a smooth, silky finish
Use caution if
- Individuals who prefer silicone-free or minimalist routines
- Those with very oily skin who may find film-forming silicones too heavy
Usage tips
Safety summary
Dimethicone/Silsesquioxane Copolymer is considered safe for use in cosmetics at typical concentrations. It has a low irritation and comedogenic risk. Some individuals may find it difficult to remove, but it does not pose known health concerns.
Research notes
Safety assessments by the Cosmetic Ingredient Review (CIR) panel have concluded that dimethicone and related silicone polymers are safe for topical use. Specific studies on this copolymer are limited, but it is widely used in the industry with a strong safety record.
Common label clues
- Typical concentration
- 1% to 10%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and many other countries. No concentration restrictions are typically imposed.
- Common uses
- Long-wear foundations, Waterproof mascara, Sunscreens, Hair styling products, Primers
- Environmental note
- As a silicone-based polymer, it is not biodegradable and may accumulate in the environment. However, it is not classified as a microplastic under current definitions.
Good to know
- This ingredient is often used in 'transfer-proof' or '24-hour wear' makeup formulas.
- It is considered safe for use in cosmetics by major regulatory bodies, including the FDA and the European Commission.
Common questions
What is Dimethicone/Silsesquioxane Copolymer in beauty products?
This is a type of silicone that creates a thin, flexible film on your skin or hair. Think of it like a very light, invisible shield that helps your makeup stay put and your sunscreen stay effective, even when you sweat or get wet. It also makes the product feel silky and smooth when you apply it.
What does Dimethicone/Silsesquioxane Copolymer do in a beauty product?
When applied, the copolymer forms a thin, even film on the skin or hair surface. This film helps other ingredients (like pigments in foundation or UV filters in sunscreen) stay in place longer. It also repels water and sweat, making the product more durable. The film is flexible, so it moves with your skin without cracking or feeling tight.
Is Dimethicone/Silsesquioxane Copolymer safe for most people?
Dimethicone/Silsesquioxane Copolymer is considered safe for use in cosmetics at typical concentrations. It has a low irritation and comedogenic risk. Some individuals may find it difficult to remove, but it does not pose known health concerns.
Who should be careful with Dimethicone/Silsesquioxane Copolymer?
Individuals who prefer silicone-free or minimalist routines Those with very oily skin who may find film-forming silicones too heavy
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.