Ingredient review

Polyurethane-46

INCI: POLYURETHANE-46

A synthetic film-former that helps makeup last longer and resist water, but offers no active skincare benefit.

beautyskincarefilm-former

In plain English

Polyurethane-46 is a man-made plastic-like ingredient that creates a thin, flexible film on your skin or lashes. This film helps makeup stay put longer, resist sweat and water, and feel smooth rather than stiff. Think of it as a clear, invisible shield that holds your makeup in place without clogging pores or causing irritation for most people.

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

Polyurethane-46 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 Polyurethane-46.
  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

Polyurethane-46 is a synthetic polymer belonging to the polyurethane family. It is produced through a chemical reaction between diisocyanates and polyols, resulting in a flexible, durable film-forming material. In cosmetics, it is used as a non-volatile film former that dries down to a clear, flexible layer.

How it works

When applied to the skin or lashes, the water or solvent in the product evaporates, leaving behind a thin polyurethane film. This film physically adheres to the surface, locking in pigments and other ingredients. Its flexibility allows the film to move with your skin without cracking or flaking, while its water-resistant nature helps the product withstand moisture.

Pros

Excellent wear time

Polyurethane-46 forms a durable film that helps makeup last through sweat, humidity, and water exposure, reducing the need for touch-ups.

Flexible finish

Unlike some stiff film-formers, polyurethane-46 remains flexible, so your makeup moves naturally with your skin without cracking or flaking.

Cons and cautions

Can be hard to remove

The water-resistant film requires an oil-based or dual-phase makeup remover to break down completely, which may be inconvenient for some.

No skincare benefit

Polyurethane-46 is purely a performance ingredient—it does not hydrate, soothe, or improve skin health, so it adds no active value beyond wear.

Best for

  • People who want long-wearing, waterproof makeup
  • Those with normal to oily skin looking for transfer-resistant formulas

Use caution if

  • Individuals who prefer lightweight, breathable makeup
  • Those with very sensitive skin that reacts to film-formers

Usage tips

Use an oil-based cleanser or micellar water to fully remove products containing polyurethane-46.
Apply a thin layer of product to avoid a heavy or tacky feel.
Pair with a hydrating primer if you have dry skin, as film-formers can sometimes emphasize texture.

Safety summary

Polyurethane-46 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, though individuals with very sensitive skin may experience mild reactions. No significant systemic toxicity has been reported from topical use.

Research notes

Safety assessments by the Cosmetic Ingredient Review (CIR) and other bodies support the use of polyurethane polymers in cosmetics. Most data come from industry studies and regulatory reviews rather than independent clinical trials, but the ingredient has a long history of safe use.

Common label clues

Typical concentration
1% to 10%
Regulatory status
Approved for use in cosmetics in the US, EU, and many other regions. The Cosmetic Ingredient Review (CIR) panel has evaluated polyurethane polymers and found them safe as used.
Common uses
Long-wear foundations, Waterproof mascaras, Lip products, Sunscreens
Environmental note
As a synthetic polymer, polyurethane-46 is not biodegradable. Its environmental impact depends on formulation and disposal, but it is not known to be a major pollutant at cosmetic use levels.

Good to know

  • Polyurethane-46 is considered safe for use in cosmetics by major regulatory bodies at typical concentrations.
  • It is often used in combination with other film-formers to fine-tune texture and durability.

Common questions

What is Polyurethane-46 in beauty products?

Polyurethane-46 is a man-made plastic-like ingredient that creates a thin, flexible film on your skin or lashes. This film helps makeup stay put longer, resist sweat and water, and feel smooth rather than stiff. Think of it as a clear, invisible shield that holds your makeup in place without clogging pores or causing irritation for most people.

What does Polyurethane-46 do in a beauty product?

When applied to the skin or lashes, the water or solvent in the product evaporates, leaving behind a thin polyurethane film. This film physically adheres to the surface, locking in pigments and other ingredients. Its flexibility allows the film to move with your skin without cracking or flaking, while its water-resistant nature helps the product withstand moisture.

Is Polyurethane-46 safe for most people?

Polyurethane-46 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, though individuals with very sensitive skin may experience mild reactions. No significant systemic toxicity has been reported from topical use.

Who should be careful with Polyurethane-46?

Individuals who prefer lightweight, breathable makeup Those with very sensitive skin that reacts to film-formers

Research sources

Cosmetic Ingredient Review (CIR) – Safety Assessment of Polyurethane PolymersOpenPubChem – Polyurethane-46OpenEuropean Chemicals Agency (ECHA) – Polyurethane-46Open

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.