Ingredient review
Polystearyl Methacrylate
INCI: Polystearyl Methacrylate
A synthetic film-former that helps makeup last longer and resist water, but may feel heavy on very oily skin.
In plain English
Polystearyl methacrylate is a synthetic ingredient that creates a thin, flexible film on your skin. This film helps makeup stay put longer, resist sweat and water, and gives a smooth, even finish. It's like a clear, invisible shield that holds your foundation or concealer in place throughout the day. Because it's a polymer, it doesn't absorb into the skin but sits on top, which can feel slightly tacky or heavy for some people, especially if you have oily skin.
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
Polystearyl Methacrylate 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 Polystearyl Methacrylate.
- 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 polymer made from stearyl methacrylate monomers. It is a film-forming agent that dries down to a flexible, water-resistant layer on the skin.
How it works
When applied, the polymer chains spread out and then link together as the solvent evaporates, forming a continuous film. This film physically locks in pigments and other ingredients, reducing transfer and smudging. It also helps control oil absorption by creating a barrier that limits sebum migration through the makeup layer.
Pros
Boosts makeup staying power
Creates a flexible film that helps foundation and concealer resist smudging, fading, and transferring onto masks or clothing for hours.
Water-resistant barrier
Forms a protective layer that repels water and sweat, making it ideal for humid conditions or long days when you need your makeup to stay intact.
Cons and cautions
Can feel heavy on oily skin
The film-forming nature may feel tacky or suffocating for those with very oily skin, potentially leading to a greasy appearance or clogged pores.
Requires double cleansing
Because it forms a water-resistant film, it often needs an oil-based cleanser or micellar water to fully remove, adding an extra step to your routine.
Best for
- People who want long-lasting foundation or concealer
- Those with normal to dry skin who prefer a dewy, locked-in finish
Use caution if
- Individuals with very oily or acne-prone skin who find film-formers clogging or heavy
Usage tips
Safety summary
Polystearyl methacrylate is considered safe for cosmetic use at typical concentrations. It has a low irritation and comedogenic risk, but individuals with very oily or sensitive skin may find it heavy or slightly tacky. No significant safety concerns have been reported in regulatory reviews.
Research notes
Limited peer-reviewed studies specifically on polystearyl methacrylate, but it is a well-established film-former in cosmetics. Safety assessments by industry panels (e.g., CIR) have concluded it is safe when used as intended. Most evidence comes from formulation science rather than clinical trials.
Common label clues
- Typical concentration
- 1–10% in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Foundations, Concealers, Sunscreens, Long-wear makeup, Eye shadows
- Environmental note
- As a synthetic polymer, it is not biodegradable and may contribute to microplastic pollution. Some brands are moving toward biodegradable alternatives.
Good to know
- Polystearyl methacrylate is often combined with silicones to improve spreadability.
- It is commonly found in 'long-wear' or '24-hour' makeup products.
- This ingredient is not absorbed into the skin, so it poses minimal risk of irritation for most people.
Common questions
What is Polystearyl Methacrylate in beauty products?
Polystearyl methacrylate is a synthetic ingredient that creates a thin, flexible film on your skin. This film helps makeup stay put longer, resist sweat and water, and gives a smooth, even finish. It's like a clear, invisible shield that holds your foundation or concealer in place throughout the day. Because it's a polymer, it doesn't absorb into the skin but sits on top, which can feel slightly tacky or heavy for some people, especially if you have oily skin.
What does Polystearyl Methacrylate do in a beauty product?
When applied, the polymer chains spread out and then link together as the solvent evaporates, forming a continuous film. This film physically locks in pigments and other ingredients, reducing transfer and smudging. It also helps control oil absorption by creating a barrier that limits sebum migration through the makeup layer.
Is Polystearyl Methacrylate safe for most people?
Polystearyl methacrylate is considered safe for cosmetic use at typical concentrations. It has a low irritation and comedogenic risk, but individuals with very oily or sensitive skin may find it heavy or slightly tacky. No significant safety concerns have been reported in regulatory reviews.
Who should be careful with Polystearyl Methacrylate?
Individuals with very oily or acne-prone skin who find film-formers clogging or 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.