A particle-form organic filter covering UVB through long-wave UVA. Photostable and barely absorbed; allowed in the EU at 10% but not approved in the US.
Bisoctrizole is an organic filter made as microfine particles dispersed in the water phase, so, like the mineral filters, it both absorbs and scatters UV. It covers UVB through UVA1 (peaks near 305 and 360 nm) and is very photostable.
It is permitted in the EU (up to 10%, including a nano form, which is not allowed in sprays), Australia and much of Asia. It is not an approved sunscreen active in the US, so US products containing it are generally imported formulas.
Its broad-spectrum absorption and stability are established in formulation and SPF/UVA testing. Toxicology reviews found no genotoxicity or reproductive toxicity and low absorption, with a wide margin of safety at 10%. Clinical outcome trials exist for sunscreens in general, not for this filter specifically.
Reviewing animal and lab data, the filter showed no genotoxicity, no reproductive or developmental effects up to 1,000 mg/kg/day, and no skin sensitisation at 30%. The calculated margin of safety exceeded 100 at 10% use in all cosmetics.