Natrol's Immune Boost Formula combines the clinically tested superfood EpiCor® with high-quality supplements such as vitamin C, vitamin D-3, selenium and zinc. EpiCor® is a fermented yeast complex. Vitamin C is a well-known vitamin, vitamin D3 is a vitamin that is the subject of much research. Many people do not get enough vitamin D from sunlight or food. Selenium and zinc are minerals. Features of Immune Boost Formula: - Daily Maintenance - Suitable for adults and children 9 years of age and older - Tips for children: mix the contents of one capsule with their favorite food. - Strengthen your body all year round with Natrol's Immune Boost.