Sodium Styrene/Acrylates Copolymer

What is Sodium Styrene/Acrylates Copolymer?

Sodium Styrene/Acrylates Copolymer is a lab-synthesized anionic polymer derived from styrene and acrylic acid monomers, neutralized with sodium to form its salt. Commonly found in makeup foundations, sunscreens, shampoos, and lotions, it functions by depositing a flexible, continuous layer on the skin or hair surface. This film helps adhere active ingredients and improves product longevity against water or rubbing. As a rheology modifier, it interacts with water and other components to build structure, preventing separation and easing application. Its light-scattering particles reduce transparency, giving creams and emulsions a smooth, uniform appearance without affecting spreadability. Derived through emulsion polymerization, it remains stable across pH ranges typical in rinse-off and leave-on formulations, supporting diverse textures from gels to thick creams.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Film former
Creates a continuous film on skin or hair to improve wear, water resistance, transfer resistance, shine, or hold in sunscreens, makeup, and styling products.
Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.
Opacifying agent
Makes a formula less transparent to create a creamy, opaque look; can also help visually mask suspended particles and improve aesthetic uniformity.

Benefits

Provides a flexible barrier that enhances makeup staying power and sunscreen water resistance.

Improves formula stability by adjusting thickness for smooth texture and even dispensing.

Creates an opaque, creamy look that masks imperfections and suspended particles for visual appeal.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Users seeking long-lasting makeup or hair styling hold.
Those with rare allergies to styrene-derived polymers.
Individuals preferring stable, non-separating lotions and creams.
People sensitive to high-molecular-weight synthetic thickeners.
People wanting visually uniform, non-transparent skincare emulsions.
Individuals preferring entirely natural or polymer-free formulations.

Safety Notes

  • Rated low hazard by safety assessments for cosmetic use.
  • Shows minimal irritation or sensitization in standardized tests.

Frequently Asked Questions about Sodium Styrene/Acrylates Copolymer

Is it safe for daily use?

Yes, safety reviews confirm it's suitable for frequent application in rinse-off and leave-on products.

Does it make products feel heavy?

No, it forms lightweight films and adjusts viscosity for comfortable, spreadable textures.

Can it be used on sensitive skin?

Generally low irritation potential, though patch testing is advisable for sensitivities.