Hydrogenated Styrene/Methyl Styrene/Indene Copolymer

What is Hydrogenated Styrene/Methyl Styrene/Indene Copolymer?

Hydrogenated Styrene/Methyl Styrene/Indene Copolymer is a synthetic, amorphous resin produced through the polymerization of styrene, methylstyrene, and indene monomers, followed by hydrogenation to enhance stability. This clear, tacky material belongs to the class of hydrocarbon copolymers commonly incorporated into color cosmetics like lipsticks, mascaras, eyeliners, and nail polishes. In formulations, it functions by thickening products to achieve optimal flow and suspension properties, preventing separation and ensuring smooth dispensing. Simultaneously, it deposits a flexible, cohesive film upon application, promoting adhesion to skin, hair, or nails while providing resistance to water, sweat, and rubbing. This dual role supports long-lasting performance in makeup without adding opacity or stiffness, and its hydrogenated structure minimizes oxidation risks for better shelf life and skin compatibility across anhydrous and emulsion-based systems.

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

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.
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.

Benefits

Improves product thickness for better stability and even application.

Forms a protective layer enhancing makeup durability and smudge resistance.

Contributes to smooth texture without heaviness or residue.

Who It's For

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

Who May Benefit Who Should Avoid
People using long-wear lip or eye products for extended hold.
Those with rare allergies to styrene-based polymers.
Individuals seeking water-resistant makeup formulations.
People preferring fully natural or plant-derived ingredients.
Users preferring stable, easy-to-apply cosmetic textures.
Individuals sensitive to film-forming resins in patch tests.

Safety Notes

  • Considered safe for cosmetic use at typical concentrations by regulatory reviews.
  • Presents low risk of irritation or comedogenicity in standard applications.

Frequently Asked Questions about Hydrogenated Styrene/Methyl Styrene/Indene Copolymer

What products contain this ingredient?

Commonly found in lipsticks, mascaras, eyeliners, and nail polishes for film-forming and viscosity benefits.

Is it safe for sensitive skin?

Generally low irritation potential based on cosmetic safety evaluations.

Does it cause breakouts?

Non-comedogenic rating indicates minimal acne risk.