Common colds are the most common human infection. The flu is less common but far more severe. Here’s the good news: In the early stages of a cold or flu, it is still possible to change the course of the illness. The immune-supporting nutrients bolster your body’s defenses, helping to reduce both the severity and duration of the illness. In human studies: Zinc lozenges reduce the duration of colds by up to 44% and the severity of symptoms by as much as 50% when initiated soon after symptoms first appear,2 Elderberry extract resolves upper respiratory symptoms up to ..