Drometrizole trisiloxane (INCI) is a lipophilicbenzotriazole derivative marketed as Mexoryl XL by L'Oréal and is used in sunscreens to absorb UV radiation. It is a broad-spectrum UV absorber with two absorption peaks, one at 303 nm (UVB) and one at 344 nm (UVA). Just like Mexoryl SX (ecamsule), it is used exclusively in products by L'Oréal owned brands. Drometrizole trisiloxane and ecamsule are often used together, because they show a synergistic effect in protection.[1]