Polystyrene
AKA “Polystyrene, Styropor
Ingredient
Ingredient Facts
Polystyrene
AKA: Styropor
Ingredient · Film Forming · EWG: 1
Synthetic
Occlusive
Clean
Ethenylbenzene, homopolymer
CAS #
9003-53-6
Form
Powder
See origin →
Functions
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Moisturizing
Strengthens Barrier
Anti-Inflammatory
Creates protective layer
Traditional Use
A synthetic plastic polymer developed in the early 20th century and adapted for cosmetic use. Used in cosmetics primarily as microbeads in exfoliating products and as a thickening or suspending agent (largely phased out due to environmental concerns).
Skin Types
all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Verified Jun 2026
Data: CosIng · EWG · CIR