Hi, I would like to know the relationship between histamine and methylation. This question arises because I have taken Benadryl for the past two days for my cough and cold. I have faced some effects on my mood particularly, such as wired feeling,irritability,anxiety and major shortness of breath . I have never felt these before with Benadryl. These symptoms remind me of the days when I was overstimulated with MB12 and such things on the B12 protocol, commonly referred to as overmethylation. Could anti-histamines provoke such reactions similar to the so called overmethylation? Is there a direct link between histamine and methylation? Will Niacin help?