"PureDefense is a targeted blend of nutrients and plant extracts including Vitamin C, D and Zinc which contribute to the normal function of the immune system. Also providing n-acetylcysteine (NAC), EpiCor® dried yeast fermentate complex, Elderberry fruit extract and quercetin. Featuring 450 mg of NAC in each serving of two capsules. EpiCor® is a dried yeast fermentate complex that has undergone published clinical research. Provides 1000 IU (25 ug) vitamin D3 in each serving of two capsules. "