I took 100 mg of niacin after diner to verify that I have high histamine. Since high histamine generally means undermethylation, I wanted to prepare myself before getting the genetic profile from 23andme. Within 5 minutes of consumption, my heart felt like it was about to explode and my face got extremely hot. I could not breathe easily either. Fortunately, initial symptoms went away within 20 seconds. It's been 30 minutes and my entire body is red like Hell Boy. Wow... I thought I was going to ER at first. Has anybody experienced something similar? Lesson learned is, if you turn red easily from alcohol, do not attempt to try niacin. I knew that 100 mg was not a low dose, but I think 50 mg would have had similar effects on my body.