After being sick, I don't usually have typical histamine reactions that others get. I really think the environment and certain foods really screw me up more so neurologically than anything. Like a brain allergy if that makes any sense. However, B12 helps with my symptoms. I take about 25 mg a day. I do have hyperadrenergic POTS however and started propanolol. I noticed the propanolol was making my tongue swollen, so I took quercetin and B12 and within a number of hours the swelling subsided. This happened 3 times, so I quit the beta blocker. I learned since that mast cell activation can happen in hyperadrenergic POTS when taking beta blockers so they should be avoided. But when I read it says B12 raises histamine. But I feel that it lowers it. Which one is it? Besides the reaction to the beta blocker, It's almost like I lack histamine compared to how I was when I was well.