Ingredient review

Hydrogenated Acetophenone/Oxymethylene Copolymer

INCI: HYDROGENATED ACETOPHENONE/OXYMETHYLENE COPOLYMER

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

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In plain English

This is a man-made polymer that forms a thin, flexible film on your skin or hair. Think of it like an invisible, breathable plastic wrap that helps makeup last longer or sunscreen stay on in water. It doesn't moisturize or treat skin—it's purely a performance ingredient for texture and wear.

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

Hydrogenated Acetophenone/Oxymethylene 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 Hydrogenated Acetophenone/Oxymethylene 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 hydrogenated acetophenone with oxymethylene. It's designed to form a continuous, flexible film when applied to skin or hair.

How it works

When the product dries, the polymer molecules link together into a thin, even layer. This film resists water, sweat, and friction, helping the product stay in place longer. It also can thicken the formula slightly for a smoother application.

Pros

Boosts wear time

Creates a flexible film that helps makeup and sunscreen stay put for hours, even in humid or wet conditions.

Water-resistant

Forms a barrier that resists water and sweat, making it ideal for swim-proof sunscreens and long-wear foundations.

Cons and cautions

No skin benefit

This ingredient does not moisturize, soothe, or treat skin—it's purely a performance enhancer for texture and durability.

Potential tightness

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

Best for

  • Anyone wanting long-wearing or waterproof makeup
  • People who need water-resistant sunscreen for swimming or sweating

Use caution if

  • Those with very dry or compromised skin barriers who prefer minimal film formers

Usage tips

Apply a moisturizer underneath products containing this polymer to avoid any tight feeling.
Use a gentle oil-based cleanser or micellar water to fully remove film-forming products at the end of the day.

Safety summary

Considered safe for topical use at typical cosmetic concentrations. Low irritation and comedogenic risk. No known toxicity concerns from regulatory bodies.

Research notes

Limited independent studies on this specific polymer, but film-forming copolymers as a class are well-studied for safety and performance. No published evidence of significant skin penetration or systemic absorption.

Common label clues

Typical concentration
0.5% to 5%
Regulatory status
Approved for use in cosmetics globally, including by the U.S. FDA and EU CosIng database, with no known restrictions at typical concentrations.
Common uses
Sunscreens, Waterproof makeup, Long-wear foundations, Hair styling products
Environmental note
As a synthetic polymer, it is not biodegradable and may persist in the environment. Some regions are beginning to regulate certain film-forming polymers in rinse-off products.

Good to know

  • This ingredient is often found in combination with other film formers for a stronger water-resistant effect.
  • It is not a sunscreen active ingredient—it only helps the sunscreen stay on skin longer.

Common questions

What is Hydrogenated Acetophenone/Oxymethylene Copolymer in beauty products?

This is a man-made polymer that forms a thin, flexible film on your skin or hair. Think of it like an invisible, breathable plastic wrap that helps makeup last longer or sunscreen stay on in water. It doesn't moisturize or treat skin—it's purely a performance ingredient for texture and wear.

What does Hydrogenated Acetophenone/Oxymethylene Copolymer do in a beauty product?

When the product dries, the polymer molecules link together into a thin, even layer. This film resists water, sweat, and friction, helping the product stay in place longer. It also can thicken the formula slightly for a smoother application.

Is Hydrogenated Acetophenone/Oxymethylene Copolymer safe for most people?

Considered safe for topical use at typical cosmetic concentrations. Low irritation and comedogenic risk. No known toxicity concerns from regulatory bodies.

Who should be careful with Hydrogenated Acetophenone/Oxymethylene Copolymer?

Those with very dry or compromised skin barriers who prefer minimal film formers

Research sources

CosIng - European CommissionOpenPersonal Care Council - Safety Assessment of Film FormersOpenPubMed - Safety of Synthetic Polymers in CosmeticsOpen

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.