I've found an interesting theme in experiments with my very own headaches. When I take coffee at the onset of the headache, the headache stops immediately in its track. However, if I take a pure 100 mg caffeine supplement at the onset of the headache, the same result does not follow and the headache persists. Therefore, I believe there is something else in coffee that helps to stop my headaches, perhaps a vasoconstrictive compound. Any ideas on what this might be?