Drometrizole Trisiloxane (Mexoryl XL)
A L'Oréal filter used in European formulations.
Banned in
- Palau
Also excluded where only mineral sunscreen is allowed
- Maui County
- Hawaiʻi County
Not approved in the US, so US sunscreens do not contain it.
Where it’s restricted
Named in the law or guidance
| Location | Status | Since |
|---|---|---|
| Palau law text ↗ | In force | January 1, 2020 |
Also not allowed under mineral-only rules
Drometrizole Trisiloxane (Mexoryl XL) isn’t named in these laws, but they allow only mineral (zinc oxide or titanium dioxide) sunscreens, so a product containing it is excluded anyway.
- Maui County (Maui, Molokaʻi, Lānaʻi) (in force since October 1, 2022)
- Hawaiʻi County (Big Island) (in force since December 1, 2022)
Why it’s regulated
In June 2010 the FDA found drometrizole trisiloxane eligible for its US sunscreen monograph at up to 15 percent, but asked for safety, effectiveness and environmental data before deciding whether it can be classed as GRASE. Under FDA rules, a product containing it may not be marketed as an OTC drug in the US unless it has an approved new drug or abbreviated new drug application.
What the reef research says
Fel et al. (2019) tested drometrizole trisiloxane, which the paper calls Mexoryl XL, on the coral Stylophora pistillata.
- Mitchelmore et al. 2021, A Critical Review of Organic Ultraviolet Filter Exposure, Hazard, and Risk to Corals, Environmental Toxicology and Chemistry 40(4):967-988
- FDA, Federal Register Vol. 75 No. 105 (2 June 2010): Drometrizole Trisiloxane Eligibility for Potential Inclusion in Sunscreen Monograph; Request for Safety, Effectiveness, and Environmental Data (Docket FDA-2003-N-0196)
Related ingredients: Ethylhexyl Triazone (Uvinul T 150), Ecamsule (Mexoryl SX)
Last reviewed October 14, 2026.