Inorganic UV Filter
Inorganic UV Filter — a mineral-based sunscreen ingredient, specifically zinc oxide or titanium dioxide, that shields skin from ultraviolet radiation. Often called physical or mineral filters, they sit largely on the skin surface and protect through a combination of absorbing, scattering, and reflecting UV light.
Key points
- The two inorganic UV filters used in cosmetics are zinc oxide and titanium dioxide.
- They protect by absorbing and scattering UV radiation, not solely by reflecting it as once believed.
- Zinc oxide offers broad UVA and UVB coverage, while titanium dioxide is stronger in the UVB and shorter UVA range.
- Mineral filters are photostable and are often chosen for sensitive or reactive skin.
Frequently asked
Do mineral sunscreens only reflect UV light?
No, zinc oxide and titanium dioxide absorb a significant portion of UV radiation as well as scattering and reflecting it, so absorption is a major part of how they work.
Why do some mineral sunscreens leave a white cast?
Zinc oxide and titanium dioxide are white and sit on the skin surface, though micronized or tinted formulations can reduce the visible cast.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
