Ingredient review

Bis-HEMA Polybutanediol/IPDI Copolymer

INCI: BIS-HEMA POLY(1,4-BUTANEDIOL)-9/IPDI COPOLYMER

A synthetic film-former that helps makeup and skincare stay put longer, but may feel tight or heavy on sensitive skin.

beautyskincarefilm-former

In plain English

This ingredient is a plastic-like polymer that dries down to form a flexible, invisible film on your skin. It's what makes some foundations and eyeliners last all day without smudging or fading. Think of it like a clear, breathable shield that locks in your makeup or active ingredients.

Review score

Safety, usefulness, and evidence

3.8Good
3.8/ 5

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
How reviews are scored

Quick decision guide

Useful, but context matters

Bis-HEMA Polybutanediol/IPDI 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Bis-HEMA Polybutanediol/IPDI Copolymer.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A synthetic copolymer created by reacting bis-HEMA (a methacrylate) with poly(1,4-butanediol) and IPDI (isophorone diisocyanate). It belongs to the polyurethane family and is designed to form a durable, flexible film on the skin.

How it works

When applied, the copolymer's solvent evaporates, leaving behind a thin, continuous film that adheres to the skin. This film physically blocks water and oil from disturbing the product underneath, improving wear time and water resistance.

Pros

Excellent staying power

Creates a durable film that helps makeup resist sweat, water, and rubbing, so your look lasts through a long day or workout.

Smooth finish

Dries down to a uniform, non-tacky layer that can help blur fine lines and create a flawless canvas for makeup.

Cons and cautions

Potential tightness

The film can feel stiff or drying on some skin types, especially if you have dry or dehydrated skin.

Removal challenge

Because it's water-resistant, you'll likely need an oil-based or micellar cleanser to fully remove it without rubbing.

Best for

  • People who want long-lasting makeup that doesn't smudge
  • Those with oily or combination skin who need extra staying power

Use caution if

  • Individuals with very dry or reactive skin who dislike a tight or heavy feel

Usage tips

Always use a double-cleansing method (oil cleanser followed by water-based cleanser) to ensure complete removal.
If you have dry skin, pair with a hydrating primer or moisturizer underneath to reduce any tight feeling.

Safety summary

Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk, but may cause tightness in sensitive or dry skin. No known serious safety concerns.

Research notes

Limited independent studies on this specific copolymer, but related polyurethane film-formers have a long history of safe use in cosmetics. Safety assessments rely on ingredient-specific data and general polymer toxicology.

Common label clues

Typical concentration
Typically 1–10% in leave-on products
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
Long-wear foundations, Waterproof eyeliners, Lip products, Sun protection formulas
Environmental note
As a synthetic polymer, it is not biodegradable and may contribute to microplastic pollution. Some brands are moving toward bio-based alternatives.

Good to know

  • This ingredient is often found in '24-hour wear' or 'waterproof' makeup products.
  • It is not water-soluble, so standard foaming cleansers may not remove it fully.

Common questions

What is Bis-HEMA Polybutanediol/IPDI Copolymer in beauty products?

This ingredient is a plastic-like polymer that dries down to form a flexible, invisible film on your skin. It's what makes some foundations and eyeliners last all day without smudging or fading. Think of it like a clear, breathable shield that locks in your makeup or active ingredients.

What does Bis-HEMA Polybutanediol/IPDI Copolymer do in a beauty product?

When applied, the copolymer's solvent evaporates, leaving behind a thin, continuous film that adheres to the skin. This film physically blocks water and oil from disturbing the product underneath, improving wear time and water resistance.

Is Bis-HEMA Polybutanediol/IPDI Copolymer safe for most people?

Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk, but may cause tightness in sensitive or dry skin. No known serious safety concerns.

Who should be careful with Bis-HEMA Polybutanediol/IPDI Copolymer?

Individuals with very dry or reactive skin who dislike a tight or heavy feel

Research sources

CosIng - European Commission ingredient databaseOpenPersonal Care Council - Safety Assessment of Polyurethane PolymersOpenPubMed - Review of film-forming polymers in cosmeticsOpen

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.