Bisoctrizole (INN/USAN, 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. It is a broad-spectrum ultraviolet radiation absorber, absorbing UVB as well as UVA rays. It also reflects and scatters UV. In primary research reports, bisoctrizole has been reported to minimally penetrate skin, and has been described as lacking estrogenic effects in vitro.