What it is
Polystyrene is a rigid polymer of styrene that, in cosmetics, is typically used as a dispersion of fine particles or as part of a film-forming system. It can add opacity, help structure the formula, and contribute to a smooth, even layer on the skin. In sunscreens it may help carry or distribute other components and refine the visual finish.
Safety & warnings
As a high-molecular-weight polymer, polystyrene is essentially inert on the skin and is not a recognized irritant or fragrance allergen.
Origin & sourcing
Synthetic petrochemical-derived polymer of styrene.
Questions everyone asks
Why is polystyrene in a sunscreen?
It is used in small amounts as a film former or texture and opacity agent, helping the product apply smoothly and form an even layer.
Does polystyrene absorb into the skin?
No. It is a large, inert polymer that stays on the surface rather than penetrating the skin.