Good Active Ingredient Sensitization Data

Drometrizole Trisiloxane

INCI: DROMETRIZOLE TRISILOXANE

CAS Number
155633-54-8
Function
Oil-soluble broad-spectrum UV filter; dual absorption peaks at ~303 nm (UVB) and ~344 nm (UVA2); provides oil-phase UVA coverage; synergistic with ecamsule (Mexoryl SX) to deliver full-spectrum UVA1+UVA2 protection in the L'Oréal Mexoryl system
Safety Rating
GOOD

Regulatory Status

🇪🇺 EU Status permitted
EU Max Conc. Approved under EU Cosmetics Regulation Annex VI; concentration limits apply
🇺🇸 US Status prohibited
US Notes Not approved in the US under the FDA OTC sunscreen monograph. Available only in products outside US jurisdiction. The L'Oréal Mexoryl system (Mexoryl SX + Mexoryl XL combination) is proprietary; US sunscreens with ecamsule must proceed via L'Oréal's NDA pathway, and drometrizole trisiloxane has no independent FDA approval pathway.

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
low
Sensitization
low

Calculate MoS for your specific formulation with the MoS Calculator.

Sensitization Profile

Contact sensitization data for Drometrizole Trisiloxane based on clinical patch test studies and IFRA standards.

Sensitization Rate
low
Allergen Class
other
EU Allergen Listed
no
Patch Test Positive Rate
0.1%
Cross-reactivity Group
none
Reaction Type
contact-dermatitis

Source: SCCS

Expert Verdict

Oil-soluble UV filter with dual UVB/UVA2 absorption peaks (303 nm and 344 nm) that complements water-soluble ecamsule in the L'Oréal Mexoryl system for full-spectrum protection. The trisiloxane backbone provides photostability and limits dermal penetration. Approved in the EU but not available in US-market products.

⚠️
Concern Level: Low

Regulatory Flags

uv-filter uva-uvb dual-peak oil-soluble photostable eu-approved not-fda-approved mexoryl-xl loreal-proprietary mexoryl-system trisiloxane-backbone uva2-primary uvb-secondary eu_cosing_listed

Frequently Asked Questions

Is Drometrizole Trisiloxane safe in cosmetics?

Oil-soluble UV filter with dual UVB/UVA2 absorption peaks (303 nm and 344 nm) that complements water-soluble ecamsule in the L'Oréal Mexoryl system for full-spectrum protection. The trisiloxane backbone provides photostability and limits dermal penetration. Approved in the EU but not available in US-market products. The EU classifies Drometrizole Trisiloxane as "permitted". Safety rating: GOOD.

Is Drometrizole Trisiloxane allowed in the EU?

Drometrizole Trisiloxane EU regulatory status: permitted. Maximum allowed concentration: Approved under EU Cosmetics Regulation Annex VI; concentration limits apply. This is based on EU Regulation 1223/2009 and its amendments.

What does Drometrizole Trisiloxane do in cosmetics?

Drometrizole Trisiloxane functions as: Oil-soluble broad-spectrum UV filter; dual absorption peaks at ~303 nm (UVB) and ~344 nm (UVA2); provides oil-phase UVA coverage; synergistic with ecamsule (Mexoryl SX) to deliver full-spectrum UVA1+UVA2 protection in the L'Oréal Mexoryl system. It is classified as a Active Ingredient in our database. CAS number: 155633-54-8.

What is the Margin of Safety for Drometrizole Trisiloxane?

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

📱

Is Drometrizole Trisiloxane in Your Products?

Scan any product label with Piro — our free ingredient scanner. Point your camera at the ingredients list and get instant safety scores for every ingredient.

Try Piro Free →

Analyze Your Full Ingredient List

Paste any INCI list into the Decoder for instant safety analysis, or calculate the Margin of Safety for Drometrizole Trisiloxane in your formulation.