I just started taking the Immune Booster and Cordyceps together and found the Immune Booster on its own provided the strongest immune boost against the common cold/flu. My daughter got sick the second week of starting kindergarten. My husband and I generally catch her colds, but this time since we both took Immune Booster, we managed to not fall sick. We can feel the symptoms brewing but the body battled on and managed to not fall. I think Immune Booster is a winner.