I guess my body got used to the Niacin since my heart isn't racing as much, but I'd prefer no Niacin in the B complex. Even if it's contradictory that I can't take the same supplement with MTHFR and COMT genetic defects, it's working for me anyway. In the beginning, I bought several bottles of coenzyme B complex brands to see which one worked best. Each brand is formulated a little different. I've been sticking with one that has at least 500 mcg of B12 since that's what worked from the start. I also need B6 (and possibly riboflavin B2). I discovered the B vitamin absorption problem was the sure cause of my EC because my lips are totally normal now. Lack of B6 can also make you feel anxious.