What it is
Drometrizole Trisiloxane is a lipophilic benzotriazole derivative carrying a silicone (trisiloxane) group, used as a broad-spectrum ultraviolet absorber. It absorbs ultraviolet radiation across the UVB and UVA ranges, with absorption peaks reported near 303 nm in the UVB region and 344 nm in the UVA region. Being oil-soluble and photostable, it resists breakdown under sun exposure, and it is noted to act synergistically with the filter ecamsule (Mexoryl SX) to enhance overall protection.
Spectrum coverage
UVA1 · UVA2 · UVB
Regional approval · max %
Safety & warnings
Origin & sourcing
Drometrizole Trisiloxane is a synthetic organic compound, a benzotriazole UV absorber modified with a trisiloxane (silicone) chain that makes it oil-soluble. It is manufactured industrially rather than obtained from any natural source.
History
Drometrizole Trisiloxane is a UV filter developed by the L'Oreal group and marketed under the trademark Mexoryl XL, described as a L'Oreal-group exclusive sunscreen agent. It appears in numerous international sunscreens from L'Oreal brands such as La Roche-Posay, Vichy, Garnier, and SkinCeuticals.
Questions everyone asks
What is Mexoryl XL?
Mexoryl XL is the trade name for drometrizole trisiloxane, an oil-soluble organic UV filter developed by the L'Oreal group that absorbs both UVA and UVB rays.
Is drometrizole trisiloxane photostable?
Yes. It is described as a photostable filter, meaning it resists breaking down during sun exposure.
Why is it not in US sunscreens?
It has not been approved for use in US sunscreens, although it is used in many products in regions such as the EU, Japan, and Korea.