Ingredient review
Stearyl Methacrylate
INCI: STEARYL METHACRYLATE
A synthetic film-former that helps makeup and sunscreen stay put longer, but offers no skincare benefit.
In plain English
Stearyl methacrylate is a man-made ingredient that forms a thin, flexible film on your skin. It's used in products like foundation, sunscreen, and mascara to help them resist water, sweat, and smudging. Think of it like a clear, invisible shield that keeps your makeup in place. It doesn't hydrate or treat your skin—it's purely a performance ingredient.
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
Stearyl 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 Stearyl 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
Stearyl methacrylate is a synthetic polymer created by reacting stearyl alcohol with methacrylic acid. It belongs to a family of ingredients called acrylates, which are widely used in cosmetics for their film-forming and texture-enhancing abilities.
How it works
When applied, stearyl methacrylate molecules link together to form a flexible, water-resistant film on the skin or hair. This film helps other ingredients (like pigments or UV filters) stay evenly distributed and last longer. It also gives products a smooth, silky feel and can thicken a formula.
Pros
Boosts wear time
Helps foundation and sunscreen stay put for hours, even in humid or sweaty conditions.
Improves texture
Gives products a silky, smooth feel that glides on easily and doesn't pill.
Cons and cautions
No skin benefit
It's purely a performance ingredient—it won't hydrate, soothe, or treat your skin.
Can feel heavy
On oily or combination skin, the film may feel sticky or overly occlusive, potentially leading to clogged pores.
Best for
- Anyone wanting long-wearing makeup or water-resistant sunscreen
- People with normal to dry skin who enjoy a smooth, film-like finish
Use caution if
- Those who prefer lightweight, breathable formulas (e.g., gel-based or water-based products)
- Individuals with very oily or acne-prone skin who may find film-formers too occlusive
Usage tips
Safety summary
Stearyl methacrylate is considered safe for cosmetic use at typical concentrations. It has a low irritation and comedogenic risk, but may feel heavy on very oily skin. No significant safety concerns have been reported in peer-reviewed literature.
Research notes
Research on stearyl methacrylate is limited to its function as a film-former. It is well-tolerated in patch tests and does not show significant skin sensitization. Most safety data come from broader acrylate copolymer studies.
Common label clues
- Typical concentration
- Typically 0.5–5% in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and many other regions. No concentration restrictions are specified for leave-on products.
- Common uses
- Foundations, Sunscreens, Waterproof mascaras, Long-wear lip products
- Environmental note
- As a synthetic polymer, stearyl methacrylate is not biodegradable. However, it is not classified as a microplastic under current definitions.
Good to know
- Stearyl methacrylate is often listed under broader INCI names like 'Acrylates Copolymer' or 'Acrylates/Stearyl Methacrylate Copolymer'.
- It is considered safe for use in cosmetics by major regulatory bodies at typical concentrations.
Common questions
What is Stearyl Methacrylate in beauty products?
Stearyl methacrylate is a man-made ingredient that forms a thin, flexible film on your skin. It's used in products like foundation, sunscreen, and mascara to help them resist water, sweat, and smudging. Think of it like a clear, invisible shield that keeps your makeup in place. It doesn't hydrate or treat your skin—it's purely a performance ingredient.
What does Stearyl Methacrylate do in a beauty product?
When applied, stearyl methacrylate molecules link together to form a flexible, water-resistant film on the skin or hair. This film helps other ingredients (like pigments or UV filters) stay evenly distributed and last longer. It also gives products a smooth, silky feel and can thicken a formula.
Is Stearyl Methacrylate safe for most people?
Stearyl methacrylate is considered safe for cosmetic use at typical concentrations. It has a low irritation and comedogenic risk, but may feel heavy on very oily skin. No significant safety concerns have been reported in peer-reviewed literature.
Who should be careful with Stearyl Methacrylate?
Those who prefer lightweight, breathable formulas (e.g., gel-based or water-based products) Individuals with very oily or acne-prone skin who may find film-formers too occlusive
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.