Bisoctrizole (INN[1]/USAN,[2] marketed by BASF as Tinosorb M, by DSM Nutritional Products as Parsol Max , by Everlight Chemical as Eversorb M, and by MPI as Milestab 360, INCI methylene bis-benzotriazolyl tetramethylbutylphenol) is a phenolic benzotriazole that is added to sunscreens to absorb UV rays.

[citation needed] Hence, bisoctrizole is formulated in sunscreen preparations as a 50% suspension, the absorber added to the water phase,[contradictory] and mineral micropigments usually added to the oil phase.

[citation needed] The bisoctrizole particles are stabilized by the surfactant decyl glucoside.

[citation needed] The compound shows very little photodegradation, and has a stabilizing effect on other UV absorbers, octyl methoxycinnamate (octinoxate) in particular.

[citation needed] In primary research reports, bisoctrizole has been reported to minimally penetrate skin,[6][non-primary source needed] and has been described as lacking estrogenic effects in vitro.