Ingredient review
Polyester-5 Polymer
INCI: ISOPHTHALIC ACID/PENTAERYTHRITOL CROSSPOLYMER BENZOATE/ISOSTEARATE
A synthetic polymer that helps makeup and skincare stay put without feeling heavy or sticky.
In plain English
This is a synthetic ingredient that forms a thin, flexible film on your skin. It helps makeup last longer, resist water, and stay smooth. Think of it like a clear, invisible shield that keeps your foundation from sliding off or your mascara from smudging. It doesn't clog pores or cause irritation for most people.
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
Polyester-5 Polymer 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 Polyester-5 Polymer.
- 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 polymer created by combining isophthalic acid, pentaerythritol, benzoic acid, and isostearic acid. The result is a crosslinked polyester resin that forms a flexible film when applied to skin.
How it works
When applied, the polymer molecules link together into a thin, breathable film that sits on the skin's surface. This film helps other ingredients (like pigments or sunscreens) stay in place, resists water and sweat, and gives a smooth, even finish. It also helps control the thickness and feel of the product.
Pros
Long-lasting wear
Helps makeup and sunscreen stay put for hours, even in heat or humidity.
Non-greasy feel
Creates a smooth, dry finish without adding oil or stickiness.
Cons and cautions
Removal can be tricky
Because it's water-resistant, you may need an oil-based or micellar cleanser to fully remove it.
May feel tight on dry skin
The film can feel slightly stiff or tight if your skin is very dry or dehydrated.
Best for
- Anyone wanting long-lasting makeup
- People with oily or combination skin who need extra staying power
- Those who wear waterproof or water-resistant products
Use caution if
- People who prefer very lightweight, minimal-ingredient routines
- Those who find film-forming ingredients uncomfortable on their skin
Usage tips
Safety summary
This ingredient is considered safe for cosmetic use. It has low irritation and comedogenic potential, making it suitable for most skin types. No significant safety concerns have been reported in standard use concentrations.
Research notes
While specific studies on this exact polymer are limited, the broader class of polyester film-formers has been reviewed by the Cosmetic Ingredient Review panel and found safe. Research supports their effectiveness in improving wear time and water resistance without significant skin irritation.
Common label clues
- Typical concentration
- 1% to 10% depending on the formula
- Regulatory status
- Approved for use in cosmetics in the US, EU, and other major markets. The Cosmetic Ingredient Review (CIR) panel has evaluated similar polyester polymers and found them safe for use in cosmetics.
- Common uses
- Long-wear foundations, Waterproof mascaras, Lip products, Sunscreens
- Environmental note
- As a synthetic polymer, it is not biodegradable. However, it is used in small amounts and is not known to accumulate in the environment in significant quantities.
Good to know
- This polymer is often listed as 'Polyester-5' on ingredient labels.
- It is commonly found in long-wear and waterproof cosmetics.
- It is considered safe for use in cosmetics by major regulatory bodies.
Common questions
What is Polyester-5 Polymer in beauty products?
This is a synthetic ingredient that forms a thin, flexible film on your skin. It helps makeup last longer, resist water, and stay smooth. Think of it like a clear, invisible shield that keeps your foundation from sliding off or your mascara from smudging. It doesn't clog pores or cause irritation for most people.
What does Polyester-5 Polymer do in a beauty product?
When applied, the polymer molecules link together into a thin, breathable film that sits on the skin's surface. This film helps other ingredients (like pigments or sunscreens) stay in place, resists water and sweat, and gives a smooth, even finish. It also helps control the thickness and feel of the product.
Is Polyester-5 Polymer safe for most people?
This ingredient is considered safe for cosmetic use. It has low irritation and comedogenic potential, making it suitable for most skin types. No significant safety concerns have been reported in standard use concentrations.
Who should be careful with Polyester-5 Polymer?
People who prefer very lightweight, minimal-ingredient routines Those who find film-forming ingredients uncomfortable on their skin
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.