Ingredient review
Sulfonated Polyester Copolymer
INCI: TEREPHTHALIC ACID/ISOPHTHALIC ACID/SODIUM ISOPHTHALIC ACID SULFONATE/GLYCOL COPOLYMER
A reliable film-former that helps makeup and sunscreen stay put longer without feeling heavy.
In plain English
This is a synthetic polymer that creates a thin, flexible film on your skin or hair. Think of it like a clear, invisible shield that helps other ingredients—like sunscreen filters or pigments—stay in place longer, even when you sweat or get wet. It's commonly used in waterproof and long-wear 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
Sulfonated Polyester 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.
- Step 1Start with the score, then check the irritation and clogging risk before judging Sulfonated Polyester Copolymer.
- 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 high-molecular-weight polyester copolymer made from terephthalic acid, isophthalic acid, and a sulfonated monomer, linked with glycol. It's designed to form a water-resistant film.
How it works
When applied, the polymer chains spread out and link together as the solvent evaporates, creating a continuous, flexible film. The sulfonate groups give it water-dispersibility, so it can be formulated into water-based products, yet once dry, the film resists wash-off by water or sweat.
Pros
Boosts water resistance
Helps sunscreen and makeup stay effective even when you sweat or go swimming, so you don't have to reapply as often.
Lightweight feel
Unlike some older film-formers, this polymer creates a thin, flexible film that doesn't feel heavy or sticky on the skin.
Cons and cautions
Requires double cleansing
Because it forms a water-resistant film, a simple water-based cleanser may not remove it fully. You'll likely need an oil-based or micellar cleanser first.
Potential tightness
On very dry or dehydrated skin, the film can create a slight tightening sensation, which some people find uncomfortable.
Best for
- Anyone wanting longer-lasting sunscreen or makeup
- People who swim or sweat a lot and need water-resistant products
Use caution if
- Those who prefer minimal-ingredient routines and avoid synthetic polymers
Usage tips
Safety summary
This ingredient has a strong safety profile with low irritation and sensitization potential. It is widely used in sunscreens and long-wear cosmetics and is considered safe for most skin types.
Research notes
Safety assessments by the Cosmetic Ingredient Review (CIR) panel have concluded that similar polyester copolymers are safe for use in cosmetics at current usage levels. No significant human or environmental toxicity has been reported.
Common label clues
- Typical concentration
- 1–10%
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (CosIng). No concentration restrictions are specified.
- Common uses
- Sunscreens, Waterproof mascaras, Long-wear foundations, Lip products
- Environmental note
- As a synthetic polymer, it is not biodegradable. However, it is used in small amounts and is not known to bioaccumulate.
Good to know
- This polymer is often listed under trade names like AQ Polymer or Polyester-5.
- It's considered safe for use in cosmetics by major regulatory bodies, including the FDA and the European Commission.
Common questions
What is Sulfonated Polyester Copolymer in beauty products?
This is a synthetic polymer that creates a thin, flexible film on your skin or hair. Think of it like a clear, invisible shield that helps other ingredients—like sunscreen filters or pigments—stay in place longer, even when you sweat or get wet. It's commonly used in waterproof and long-wear products.
What does Sulfonated Polyester Copolymer do in a beauty product?
When applied, the polymer chains spread out and link together as the solvent evaporates, creating a continuous, flexible film. The sulfonate groups give it water-dispersibility, so it can be formulated into water-based products, yet once dry, the film resists wash-off by water or sweat.
Is Sulfonated Polyester Copolymer safe for most people?
This ingredient has a strong safety profile with low irritation and sensitization potential. It is widely used in sunscreens and long-wear cosmetics and is considered safe for most skin types.
Who should be careful with Sulfonated Polyester Copolymer?
Those who prefer minimal-ingredient routines and avoid synthetic polymers
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.