Polystyrene
molecular structure · PubChem
AKA: Styropor
Synthetic
Occlusive
Clean
Ethenylbenzene, homopolymer
CAS #
9003-53-6
Form
Powder
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
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: CosIng · EWG · CIR