Ingredient review
Isocyanurate Trimer Crosspolymer
INCI: HEA/IPDI Isocyanurate Trimer/PG Crosspolymer
A synthetic film-former that helps makeup last longer and resist water, but may feel tight or stiff on some skin types.
In plain English
This ingredient is a type of plastic-like polymer that forms a thin, flexible film on the skin or hair. It is commonly used in long-wear and waterproof cosmetics to help the product stay in place and resist smudging or fading. Think of it as a clear, invisible shield that locks in your makeup.
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
Isocyanurate Trimer Crosspolymer 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 Isocyanurate Trimer Crosspolymer.
- 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 crosslinked polymer created from hydroxyethyl acrylate (HEA), isophorone diisocyanate (IPDI), and propylene glycol (PG). It forms a three-dimensional network that creates a durable film.
How it works
When applied, the polymer chains spread out and then crosslink as the solvent evaporates, forming a continuous, flexible film that adheres to the skin or hair. This film physically blocks water and oil from disturbing the product underneath, providing long-lasting wear and water resistance.
Pros
Excellent wear time
Helps makeup last through sweat, humidity, and long days without fading or smudging.
Water-resistant barrier
Creates a protective film that repels water, making it ideal for waterproof mascaras and foundations.
Cons and cautions
Can feel tight
The film may create a stiff or tight sensation on the skin, especially if you have dry or sensitive skin.
Requires double cleansing
Because it forms a durable film, it often needs an oil-based cleanser or micellar water to remove completely.
Best for
- People who need long-wear or waterproof makeup for events or humid conditions
- Those with oily skin who want makeup to stay put without melting
Use caution if
- Individuals with very dry or dehydrated skin who may find film-formers uncomfortable
- Anyone who prefers minimal, easily removable makeup
Usage tips
Safety summary
Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk. However, individuals with very sensitive or dry skin may experience tightness or discomfort.
Research notes
Limited peer-reviewed studies specifically on this exact polymer, but film-forming polymers as a class are well-studied for cosmetic use. Safety assessments by industry panels (e.g., CIR) support their use at low concentrations.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. No specific restrictions at typical use levels.
- Common uses
- Long-wear foundations, Waterproof mascaras, 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 biodegradable alternatives.
Good to know
- This polymer is often found in 'transfer-proof' or '24-hour wear' makeup formulas.
- It is not water-soluble, so water alone won't remove it.
Common questions
What is Isocyanurate Trimer Crosspolymer in beauty products?
This ingredient is a type of plastic-like polymer that forms a thin, flexible film on the skin or hair. It is commonly used in long-wear and waterproof cosmetics to help the product stay in place and resist smudging or fading. Think of it as a clear, invisible shield that locks in your makeup.
What does Isocyanurate Trimer Crosspolymer do in a beauty product?
When applied, the polymer chains spread out and then crosslink as the solvent evaporates, forming a continuous, flexible film that adheres to the skin or hair. This film physically blocks water and oil from disturbing the product underneath, providing long-lasting wear and water resistance.
Is Isocyanurate Trimer Crosspolymer safe for most people?
Generally considered safe for topical use at typical concentrations. Low irritation and comedogenic risk. However, individuals with very sensitive or dry skin may experience tightness or discomfort.
Who should be careful with Isocyanurate Trimer Crosspolymer?
Individuals with very dry or dehydrated skin who may find film-formers uncomfortable Anyone who prefers minimal, easily removable makeup
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.