A Mexican study showed that beta-sitosterol dose-dependently reduced the level of free radicals in mice by up to 78 percent .
A Chinese study lead by Li concluded that "beta-sitosterol confers a radioprotective effect on thymocytes by regulation of the intracellular redox balance which is carried out via the scavenging of ROS and maintenance of mitochondrial membrane stability." Li and co-workers tested the effect of beta-sitosterol on cultured thymus cells. They found that phytochemical reduced irradiation-induced cell death, DNA damage and intracellular reactive oxygen species, but increased antioxidant enzymes .
 Paniagua-Pérez R, Madrigal-Bujaidar E, Reyes-Cadena S, Alvarez-González I, Sánchez-Chapul L, Pérez-Gallaga J, Hernández N, Flores-Mondragón G, Velasco O. " Cell protection induced by beta-sitosterol: inhibition of genotoxic damage, stimulation of lymphocyte production, and determination of its antioxidant capacity. " Arch Toxicol. 2008 Feb 6.
 Li CR, Zhou Z, Lin RX, Zhu D, Sun YN, Tian LL, Li L, Gao Y, Wang SQ. " beta-sitosterol decreases irradiation-induced thymocyte early damage by regulation of the intracellular redox balance and maintenance of mitochondrial membrane stability." J Cell Biochem. 2007 Oct 15;102(3):748-58.