Ingredient review
IPDI/Polybutanediol Crosspolymer
INCI: IPDI/POLY(1,4-BUTANEDIOL)-14 CROSSPOLYMER
A synthetic film-former that helps products stay put and resist water, but offers no direct skin benefit.
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 spread smoothly, feel silky, and stay in place longer, even when you sweat or get wet. Think of it as a clear, invisible shield that helps your makeup or sunscreen hold on better.
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
IPDI/Polybutanediol 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 IPDI/Polybutanediol 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 synthetic crosslinked polymer made from isophorone diisocyanate (IPDI) and poly(1,4-butanediol). It belongs to the polyurethane family and is designed to create a flexible, water-resistant film on the skin.
How it works
When applied, the polymer molecules link together (crosslink) to form a continuous, flexible film on the skin's surface. This film helps other ingredients adhere better, improves water resistance, and gives a smooth, silky feel. It also thickens the product slightly, making it easier to apply evenly.
Pros
Boosts water resistance
Helps sunscreen and makeup stay effective longer when you sweat or swim, reducing the need for frequent reapplication.
Improves texture and feel
Creates a smooth, silky finish that makes products easier to apply and more comfortable to wear.
Cons and cautions
No active skin benefit
This ingredient only improves product performance; it doesn't hydrate, soothe, or treat skin conditions.
Synthetic origin
Made from petrochemicals, which may be a concern for those seeking natural or 'clean' beauty products.
Best for
- Anyone wanting longer-lasting sunscreen or makeup
- People who swim, sweat, or live in humid climates
Use caution if
- Those who prefer only naturally-derived ingredients
- People with very sensitive skin who react to film-formers (rare)
Usage tips
Safety summary
IPDI/Polybutanediol Crosspolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. However, as a synthetic ingredient, it may not be suitable for those seeking exclusively natural formulations.
Research notes
Safety assessments by the Cosmetic Ingredient Review (CIR) panel and other bodies have found polyurethane film-formers to be safe in cosmetics. No significant human or environmental toxicity has been reported at typical use levels.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and other major markets. No known restrictions at typical use levels.
- Common uses
- Sunscreens, Water-resistant makeup, Long-wear foundations, Eye liners, Lip products
- Environmental note
- As a synthetic polymer, it is not biodegradable and may persist in the environment. However, it is used in small amounts and is not considered a major environmental concern.
Good to know
- This ingredient is often listed under the broader category 'Polyurethane-14' on some product labels.
- It is considered safe by major regulatory bodies when used in typical cosmetic concentrations.
Common questions
What is IPDI/Polybutanediol Crosspolymer 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 spread smoothly, feel silky, and stay in place longer, even when you sweat or get wet. Think of it as a clear, invisible shield that helps your makeup or sunscreen hold on better.
What does IPDI/Polybutanediol Crosspolymer do in a beauty product?
When applied, the polymer molecules link together (crosslink) to form a continuous, flexible film on the skin's surface. This film helps other ingredients adhere better, improves water resistance, and gives a smooth, silky feel. It also thickens the product slightly, making it easier to apply evenly.
Is IPDI/Polybutanediol Crosspolymer safe for most people?
IPDI/Polybutanediol Crosspolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. However, as a synthetic ingredient, it may not be suitable for those seeking exclusively natural formulations.
Who should be careful with IPDI/Polybutanediol Crosspolymer?
Those who prefer only naturally-derived ingredients People with very sensitive skin who react to film-formers (rare)
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.