At the first dose, brain fog and fatigue lifted, just like that. These are symptoms of longCOVID, which I think I have. I am thankful to Remedylink and Life Enthusiast for making this superior product available. One of the enzymes on this formula is Lumbrokinase, which is the subject of a clinical trial to see if it improves symptoms of LongCOVID, ME/CFS, & LongLyme disease.