ZENITH NUTRITION’S Immune Formula contains Colostrum SUPER so it actually replenishes your immune defense system with the full range of Immunoglobulins including IgA, IgD, IgE, IgG and IgM. Colostrum is the only supplement you can take to add back antibodies and immune factors. Immune Formula helps you maintain a strong immune system with dual action in the bloodstream and in the GI tract where your need for immune defense is greatest. It helps maintain a robust intestinal lining and promotes healthy intestinal flora.Colostrum is the pre-milk fluid produced by all mammals during the first 24-48 hours after giving birth. In order to maintain a healthy immune system, your body needs immune-building antibodies, known as Immunoglobulins (IgG). Bovine colostrum is produced by a female cow, and is the best known source of IgG. Colostrum is high in protein and antibodies, and has no known side effects.