I have noticed a slight improvement in headache and dizziness problems taking l-methionine. However, it has not helped with ibs-d. Could someone detail how SAMe differs and could help. I suspect histamine is at play because H2 antihistamines seem to firm up the stools, though do nothing for urgency, and allegra gives me slightly more energy. I also have the MAO297 mutation, but the low-serotonin protocol did not seem to help.