Vitamins C and E help protect cells from oxidative stress with their antioxidant properties. Vitamin C also helps to regenerate the reduced form of Vitamin E, as well as contributing to normal collagen formation and the normal function of the immune system. Vitamins C and E help protect cells from oxidative stress with their antioxidant properties. Vitamin C also helps to regenerate the reduced form of Vitamin E, as well as contributing to normal collagen formation and the normal function of the immune system.