Vitamin C
Vitamin C is a potent antioxidant that has been studied for many years for its immune-supporting effects. Through its antioxidant functions, vitamin C has been shown to protect important immune cells from oxidative damage. Data shows vitamin C is heavily concentrated in macrophages, supports lymphocyte activity, modulates cytokine release, improves endothelial function, restores mitochondrial function, and can directly support a challenged immune system. Of particular interest, vitamin C has been shown to recycle oxidized quercetin back to its parent compound, which supports a robust immune response while increasing the efficacy of quercetin.