Ingredient review

Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer

INCI: DIISOPROPANOLAMINE/METHYLHEXAHYDROPHTHALIC ANHYDRIDE NONANOATE COPOLYMER

A synthetic film-former that helps products stay put, but offers no active skincare benefit.

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In plain English

This is a man-made polymer that dries down to form a thin, flexible film on your skin or hair. Think of it like an invisible, breathable plastic wrap that helps makeup last longer or keeps hair in place. It's not absorbed into the skin and works purely on the surface.

Review score

Safety, usefulness, and evidence

3.5Good
3.5/ 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

Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer.
  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

A synthetic copolymer created by reacting diisopropanolamine with methylhexahydrophthalic anhydride and nonanoic acid. It belongs to a class of ingredients called film formers, which are common in long-wear and water-resistant formulas.

How it works

When applied, the copolymer's molecules link together as the solvent (usually water or alcohol) evaporates, forming a continuous, flexible film. This film physically locks in pigments or other ingredients, resists water and sweat, and helps maintain the product's original appearance for hours.

Pros

Long-lasting wear

Helps makeup and sunscreen stay put for hours, reducing the need for frequent touch-ups.

Water resistance

Creates a barrier that resists sweat and humidity, making it ideal for active days or humid climates.

Cons and cautions

Removal difficulty

The film can be stubborn to remove, often requiring an oil-based cleanser or double cleansing to avoid residue.

Potential tightness

On very dry or sensitive skin, the dried film may feel tight or slightly uncomfortable, especially if layered heavily.

Best for

  • Anyone wanting longer-lasting makeup or sunscreen
  • People with normal to oily skin who prefer matte, transfer-resistant finishes

Use caution if

  • Those with very dry or compromised skin barriers who may find film-formers uncomfortable

Usage tips

Use an oil-based cleanser or micellar water to fully remove products containing this polymer.
Apply in thin, even layers to avoid a heavy or cakey feel.
Pair with a moisturizer underneath if you have dry skin to minimize any tight sensation.

Safety summary

Generally recognized as safe for topical cosmetic use at typical concentrations. Low irritation and comedogenic risk. No significant safety concerns have been raised by regulatory bodies or dermatological reviews.

Research notes

Limited peer-reviewed studies specifically on this copolymer, but it is chemically similar to other well-studied film-forming polymers used in cosmetics. Safety assessments rely on analog data and ingredient-specific toxicology reports from manufacturers.

Common label clues

Typical concentration
0.5% to 5%
Regulatory status
Approved for use in cosmetics in the US, EU, and many other regions. No specific restrictions beyond general cosmetic safety requirements.
Common uses
Hair styling products, Water-resistant sunscreens, Long-wear makeup
Environmental note
As a synthetic polymer, it may not be biodegradable. However, it is used in very small amounts per product, so its environmental impact is considered low relative to other packaging and formulation factors.

Good to know

  • This ingredient is not absorbed into the skin; it works only on the surface.
  • It is often listed near the end of ingredient lists because it is used in low concentrations.
  • The long chemical name simply describes its structure—it's a standard film-former, not a novel or exotic ingredient.

Common questions

What is Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer in beauty products?

This is a man-made polymer that dries down to form a thin, flexible film on your skin or hair. Think of it like an invisible, breathable plastic wrap that helps makeup last longer or keeps hair in place. It's not absorbed into the skin and works purely on the surface.

What does Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer do in a beauty product?

When applied, the copolymer's molecules link together as the solvent (usually water or alcohol) evaporates, forming a continuous, flexible film. This film physically locks in pigments or other ingredients, resists water and sweat, and helps maintain the product's original appearance for hours.

Is Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer safe for most people?

Generally recognized as safe for topical cosmetic use at typical concentrations. Low irritation and comedogenic risk. No significant safety concerns have been raised by regulatory bodies or dermatological reviews.

Who should be careful with Diisopropanolamine/Methylhexahydrophthalic Anhydride Nonanoate Copolymer?

Those with very dry or compromised skin barriers who may find film-formers uncomfortable

Research sources

Cosmetic Ingredient Review (CIR) - Safety Assessment of Film-Forming PolymersOpenEuropean Chemicals Agency (ECHA) - Substance InformationOpenPersonal Care Products Council - Ingredient DatabaseOpen

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.