Ingredient review
Polyurethane-38
INCI: POLYURETHANE-38
Polyurethane-38 is a synthetic film-former that helps makeup last longer and resist water, but it may feel heavy on some skin types.
In plain English
Polyurethane-38 is a plastic-like ingredient that creates a thin, flexible film on your skin or lashes. It helps makeup stay put, resist sweat and water, and feel smooth. Think of it as a clear, invisible shield that keeps your foundation or mascara from smudging or fading. It's common in long-wear and waterproof products.
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
Polyurethane-38 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 Polyurethane-38.
- 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
Polyurethane-38 is a synthetic polymer, part of the polyurethane family, engineered to form a durable yet flexible film on skin or hair. It is not a natural ingredient and is produced through chemical synthesis.
How it works
When applied, the water or solvent in the product evaporates, leaving behind a thin, continuous film of polyurethane. This film adheres to the skin or lashes, creating a barrier that resists water, oil, and friction, thereby extending the wear time of the product.
Pros
Excellent wear time
Polyurethane-38 helps makeup stay intact for hours, even in humid or sweaty conditions, reducing the need for touch-ups.
Water-resistant barrier
It forms a protective layer that repels water and oil, making it ideal for waterproof mascaras and long-wear foundations.
Cons and cautions
Can feel heavy
On dry or sensitive skin, the film may feel tight, sticky, or uncomfortable, especially if layered under multiple products.
Removal challenges
Because it's water-resistant, you may need an oil-based or dual-phase makeup remover to fully cleanse it off, which can be inconvenient.
Best for
- People who need long-lasting makeup for events or long days
- Those with oily skin who struggle with makeup fading
Use caution if
- Those with very dry or sensitive skin who find film-formers uncomfortable
- Anyone preferring a minimalist or natural ingredient list
Usage tips
Safety summary
Polyurethane-38 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, but individuals with very sensitive skin may experience discomfort from the film-forming effect.
Research notes
Safety assessments of polyurethane polymers in cosmetics generally support their use as film-formers. Specific studies on Polyurethane-38 are limited, but the broader class is well-tolerated. No significant toxicity or allergenicity has been reported in peer-reviewed literature.
Common label clues
- Typical concentration
- 1–10%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and many other regions. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Long-wear foundations, Waterproof mascaras, Lip products, Setting sprays
- Environmental note
- As a synthetic polymer, Polyurethane-38 is not biodegradable. Its environmental impact depends on formulation and disposal methods.
Good to know
- Polyurethane-38 is often listed near the end of ingredient lists, indicating a low concentration.
- It is not the same as polyurethane foam used in furniture — cosmetic-grade polyurethanes are specifically designed for skin safety.
Common questions
What is Polyurethane-38 in beauty products?
Polyurethane-38 is a plastic-like ingredient that creates a thin, flexible film on your skin or lashes. It helps makeup stay put, resist sweat and water, and feel smooth. Think of it as a clear, invisible shield that keeps your foundation or mascara from smudging or fading. It's common in long-wear and waterproof products.
What does Polyurethane-38 do in a beauty product?
When applied, the water or solvent in the product evaporates, leaving behind a thin, continuous film of polyurethane. This film adheres to the skin or lashes, creating a barrier that resists water, oil, and friction, thereby extending the wear time of the product.
Is Polyurethane-38 safe for most people?
Polyurethane-38 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, but individuals with very sensitive skin may experience discomfort from the film-forming effect.
Who should be careful with Polyurethane-38?
Those with very dry or sensitive skin who find film-formers uncomfortable Anyone preferring a minimalist or natural ingredient list
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.