I would like to add to the comment on being allergic to yeast. Some people have a true allergic reaction. This is obvious and one should stop using it immediately. Others have an immune reaction, but not an IgE (true allergy) reaction. Instead you might have bad fatigue, anxiety, brain fog, stomach issues, feel flu like, etc. However, those are symptoms alot of people have when pathogenic yeasts die and release toxins too. Basically, if you have that kind of a reaction and it doesnt start to let up after a few days or a week, begin to suspect it is a reaction to the yeast you are taking.