Wikipedia
Ecamsule
Ecamsule ( USAN, trade name Mexoryl SX, INCI terephthalylidene dicamphor sulfonic acid) is an organic compound which is added to many sunscreens to filter out UVA rays. It is a benzylidene camphor derivative, many of which are known for their excellent photostability.
Although there are a few different UV absorbers with the trade name Mexoryl, only two of them are widely used where approved. Mexoryl SX (water-soluble) and Mexoryl XL (INCI Drometrizole trisiloxane, oil-soluble). Together they show a synergistic effect in protection. The patents are held by L'Oréal. Sunscreens containing ecamsule are exclusive to L'Oréal and its brands.