Ingredient review
Polyoxyisobutylene/Methylene Urea Copolymer
INCI: Polyoxyisobutylene/Methylene Urea Copolymer
A synthetic polymer that helps products stay put on skin, especially in water-resistant formulas.
In plain English
This ingredient is a type of plastic-like polymer that forms a thin, flexible film on your skin. It's added to products like sunscreen and long-wear makeup to help them resist water, sweat, and rubbing off. Think of it as a gentle, invisible shield that helps your product stay effective longer.
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
Polyoxyisobutylene/Methylene Urea 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 Polyoxyisobutylene/Methylene Urea 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 copolymer created by combining polyoxyisobutylene and methylene urea, designed to form a flexible, water-resistant film on the skin.
How it works
When applied, the polymer molecules link together to create a continuous, breathable film on the skin's surface. This film physically blocks water and oil from breaking down the product underneath, enhancing durability and water resistance.
Pros
Boosts water resistance
Helps sunscreens and makeup stay effective even when you sweat or swim, so you don't have to reapply as often.
Extends wear time
Creates a flexible film that keeps foundation and eye makeup from fading or creasing throughout the day.
Cons and cautions
Can feel heavy on oily skin
The film-forming nature may feel sticky or occlusive for those with very oily skin, potentially contributing to a greasy feel.
Limited safety data
While generally considered safe, there is less published research on this specific polymer compared to more common film-formers like acrylates.
Best for
- People who need long-wearing or water-resistant sunscreens and makeup
- Those with normal to dry skin looking for extra product staying power
Use caution if
- Individuals with very oily or acne-prone skin who may find film-formers too occlusive
Usage tips
Safety summary
Polyoxyisobutylene/Methylene Urea Copolymer is considered safe for topical use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, though individuals with very sensitive or oily skin should patch test first.
Research notes
Evidence is based on general polymer safety data and industry use. No major safety concerns have been reported, but independent long-term studies are limited.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Sunscreens, Waterproof makeup, Long-wear foundations
- Environmental note
- As a synthetic polymer, it may not be biodegradable. However, it is used in low concentrations and is not known to bioaccumulate significantly.
Good to know
- This polymer is often combined with other film-formers to fine-tune texture and water resistance.
- It is not known to clog pores, but individual reactions can vary.
Common questions
What is Polyoxyisobutylene/Methylene Urea Copolymer in beauty products?
This ingredient is a type of plastic-like polymer that forms a thin, flexible film on your skin. It's added to products like sunscreen and long-wear makeup to help them resist water, sweat, and rubbing off. Think of it as a gentle, invisible shield that helps your product stay effective longer.
What does Polyoxyisobutylene/Methylene Urea Copolymer do in a beauty product?
When applied, the polymer molecules link together to create a continuous, breathable film on the skin's surface. This film physically blocks water and oil from breaking down the product underneath, enhancing durability and water resistance.
Is Polyoxyisobutylene/Methylene Urea Copolymer safe for most people?
Polyoxyisobutylene/Methylene Urea Copolymer is considered safe for topical use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, though individuals with very sensitive or oily skin should patch test first.
Who should be careful with Polyoxyisobutylene/Methylene Urea Copolymer?
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.