Cosmetic ingredient

DROMETRIZOLE TRISILOXANE

Drometrizole Trisiloxane is an organic ultraviolet filter used in sunscreens and other cosmetics intended for sun protection. It belongs to the benzotriazole family and includes siloxane groups, which distinguishes it from mineral filters such as zinc oxide and titanium dioxide that function as particles in a formula.

2D molecular structure

CAS number

155633-54-8

Molecular formula

C24H39N3O3Si3

Molecular weight

501.8

Chemical name

Phenol,2-(2H-Benzotriazol-2-yl)-4-Methyl-6-(2-Methyl-3-(1,3,3,3-Tetramethyl-1-(Trimethylsilyl)Oxy)-Disiloxanyl)Propyl

InChIKey

HUVYTMDMDZRHBN-UHFFFAOYSA-N

DROMETRIZOLE TRISILOXANE: what it is

It is not a botanical extract or an oil; it is made by chemical synthesis. Drometrizole Trisiloxane absorbs part of the radiation in the UVA and UVB ranges and is described as photostable. That matters because a filter needs to retain its light-absorbing ability while the finished formula is exposed to light.

DROMETRIZOLE TRISILOXANE: what it does in cosmetics

In sunscreen, Drometrizole Trisiloxane helps make up the part of the formula that absorbs UV radiation. For someone reading an ingredient list, this means it can contribute to broad-spectrum protection when it is combined with other filters in a product whose SPF and UVA protection have been tested.

The ingredient does not determine a sunscreen's performance on its own. Final coverage depends on the permitted concentration, the other filters, the film the product forms on skin, and testing of the finished product. The literature also reports one clinical case of allergic contact dermatitis linked to it; a single case does not establish how often this happens, but it supports stopping use and seeking advice if irritation or allergy symptoms appear.

DROMETRIZOLE TRISILOXANE: conditions and care

In the European Union, Drometrizole Trisiloxane is listed as a UV filter at a maximum of 15% in the ready-to-use product. One clinical case described allergic contact dermatitis; stop use if signs of a reaction appear.

Use limits