Ingredient review

Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer

INCI: AMMONIUM ACRYLOYLDIMETHYLTAURATE/STEARETH-25 METHACRYLATE CROSSPOLYMER

A reliable synthetic thickener that gives products a silky, non-sticky feel without clogging pores.

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In plain English

This is a synthetic ingredient used to thicken and stabilize water-based skincare products. It helps create a smooth, lightweight gel texture that spreads easily and doesn't feel sticky or greasy on the skin. Think of it as a helper that keeps the product's consistency nice and even, so your lotion or serum doesn't separate or feel watery.

Quick decision guide

Useful, but context matters

Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer.
  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 high-molecular-weight synthetic polymer that swells in water to form a gel-like network. It is made by crosslinking two types of monomers: one that attracts water and another that helps the ingredient blend with oils and other ingredients.

How it works

When mixed into a water-based formula, the polymer particles absorb water and expand, creating a three-dimensional network that thickens the product. This network also helps stabilize emulsions (mixtures of oil and water) by preventing them from separating, and it gives the final product a smooth, elegant feel on the skin.

Pros

Lightweight feel

Creates a silky, non-greasy texture that absorbs quickly, making it ideal for gel-based moisturizers and serums.

Stable formulas

Helps keep oil and water mixed together, so your product stays smooth and doesn't separate over time.

Cons and cautions

Synthetic origin

Made in a lab, which may be a turn-off for people who prefer naturally derived thickeners like xanthan gum.

Potential tackiness

If used at too high a concentration, it can leave a slightly sticky or tacky residue on the skin.

Best for

  • Anyone who enjoys lightweight gel creams or serums
  • People with oily or combination skin looking for a matte finish

Use caution if

  • Those who strictly avoid synthetic ingredients in their routine

Usage tips

Apply gel-based products containing this ingredient to slightly damp skin for easier spreadability.
Layer with lighter serums first, then follow with a thicker cream if needed.

Safety summary

Extensively tested and considered safe for topical use. It has a very low irritation and comedogenic (pore-clogging) risk, making it suitable for sensitive and acne-prone skin.

Research notes

Used widely in cosmetics for decades with a strong safety record. No significant adverse effects have been reported in normal use. Most data comes from industry safety assessments rather than independent clinical trials.

Common label clues

Typical concentration
0.1% to 2%
Regulatory status
Approved for use in cosmetics globally, including by the U.S. FDA and EU CosIng database, with no known restrictions.
Common uses
Gel creams, Serums, Lotions, Sunscreens, Makeup
Environmental note
As a synthetic polymer, it is not biodegradable, but it is used in very small amounts and is not known to accumulate in the environment.

Good to know

  • This ingredient is often used in 'water gel' formulas that feel refreshing and cool on the skin.
  • It is considered very safe and non-irritating, even for sensitive skin types.

Common questions

What is Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer in beauty products?

This is a synthetic ingredient used to thicken and stabilize water-based skincare products. It helps create a smooth, lightweight gel texture that spreads easily and doesn't feel sticky or greasy on the skin. Think of it as a helper that keeps the product's consistency nice and even, so your lotion or serum doesn't separate or feel watery.

What does Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer do in a beauty product?

When mixed into a water-based formula, the polymer particles absorb water and expand, creating a three-dimensional network that thickens the product. This network also helps stabilize emulsions (mixtures of oil and water) by preventing them from separating, and it gives the final product a smooth, elegant feel on the skin.

Is Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer safe for most people?

Extensively tested and considered safe for topical use. It has a very low irritation and comedogenic (pore-clogging) risk, making it suitable for sensitive and acne-prone skin.

Who should be careful with Ammonium Acryloyldimethyltaurate/Steareth-25 Methacrylate Crosspolymer?

Those who strictly avoid synthetic ingredients in their routine

Research sources

CosIng - European Commission databaseOpenPersonal Care Council - Safety AssessmentOpen

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.