Ingredient review
Butyl Methacrylate Crosspolymer
INCI: BUTYL METHACRYLATE/DMAPA ACRYLATES/VINYLACETAMIDE CROSSPOLYMER
A synthetic film-former that helps products stay put and resist water, but offers no active skincare benefit.
In plain English
This is a synthetic polymer—a type of plastic-like ingredient—that dries down to form a thin, flexible film on your skin or hair. It's used to make makeup last longer, sunscreen more water-resistant, and hair products hold their shape. Think of it like a clear, invisible shield that helps the product stay where you put 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
Butyl Methacrylate 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 Butyl Methacrylate 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 high-molecular-weight synthetic polymer created by crosslinking three monomers: butyl methacrylate, DMAPA acrylates, and vinylacetamide. It is designed to form a durable yet flexible film when applied to skin or hair.
How it works
When the product is applied and the water or solvent evaporates, the polymer chains link together into a continuous film. This film physically locks in other ingredients (like sunscreen filters or pigments) and resists removal by water, sweat, or friction.
Pros
Boosts water resistance
Helps sunscreen and makeup stay effective even when you sweat or swim, reducing the need for frequent reapplication.
Extends wear time
Keeps foundation, eyeliner, or lipstick in place for hours without smudging or fading.
Cons and cautions
Can feel tight
The film it forms may feel stiff or drying on skin, especially for those with dry or sensitive skin types.
Requires double cleansing
Because it's water-resistant, you may need an oil-based cleanser or micellar water to fully remove it, adding an extra step to your routine.
Best for
- Anyone wanting long-wear or water-resistant makeup
- People using water-resistant sunscreens for outdoor activities
- Those who like strong-hold hair styling products
Use caution if
- People with very dry or dehydrated skin who prefer lightweight, breathable formulas
- Those who dislike a 'tight' feeling from film-forming products
Usage tips
Safety summary
Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk. No known significant health concerns from cosmetic use.
Research notes
Safety data is based on analogy to similar acrylate polymers reviewed by the CIR panel. No specific published studies on this exact crosspolymer were found, but the class is well-established in cosmetics.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. The Cosmetic Ingredient Review (CIR) panel has evaluated similar acrylate crosspolymers and found them safe when formulated appropriately.
- Common uses
- Sunscreens, Long-wear makeup, Hair styling products, Water-resistant formulas
- Environmental note
- As a synthetic polymer, it is not biodegradable. However, it is used in small amounts and is not known to bioaccumulate. Some manufacturers are exploring bio-based alternatives.
Good to know
- This polymer is often used in combination with other film-formers to fine-tune the feel and durability of the final product.
- It is considered safe for use in cosmetics by major regulatory bodies at typical concentrations.
Common questions
What is Butyl Methacrylate Crosspolymer in beauty products?
This is a synthetic polymer—a type of plastic-like ingredient—that dries down to form a thin, flexible film on your skin or hair. It's used to make makeup last longer, sunscreen more water-resistant, and hair products hold their shape. Think of it like a clear, invisible shield that helps the product stay where you put it.
What does Butyl Methacrylate Crosspolymer do in a beauty product?
When the product is applied and the water or solvent evaporates, the polymer chains link together into a continuous film. This film physically locks in other ingredients (like sunscreen filters or pigments) and resists removal by water, sweat, or friction.
Is Butyl Methacrylate Crosspolymer safe for most people?
Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk. No known significant health concerns from cosmetic use.
Who should be careful with Butyl Methacrylate Crosspolymer?
People with very dry or dehydrated skin who prefer lightweight, breathable formulas Those who dislike a 'tight' feeling from film-forming products
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.