After 6 months of testing different diets to try to solve my migraines, I eventually discovered an ultra-low histamine diet resulted in a ~90% decrease in my headaches. Then I began trying different DAO products before eating foods with histamine, but the headaches returned. I eventually discovered NaturDAO (available via Amazon) and its much higher 1,000,000 HDU per pill. Taking two of these before any meal or coffee finally worked to stop the food-induced migraines for me. Hope this helps.