Immunity Booster contains formula that is targeted to strengthen the Immune System via multiple bio-mechanisms. , Vitamin C - Potent Anti-Oxidant & promotes white blood cell function which protects the body from infections. , Zinc - Development & function of cells mediating Immunity. , Selenium - Helps fight cell-damaging free radicals in body & Boosts Immune system , Elderberry - Helps combat Cold & Flu, Supports Immune defenses & Anti-oxidant rich. , Echinacea - Increase the number of white blood cells, which fight infections & helps boosts Immune system.