how much CBD oil should I take for a migraine? the oil I have is 25mg CBD per 1ml. Thx in advance

Make sure the CBD oil also has the other active compounds found in cannabis; THC, terpenes and other compounds. Whole plant preparations are far superior to isolated cannabinoids. They all work together and have a synergystic effect. CBD only formulations dont seem to be as effective. I would start with a small dose, observe for results and increase dose as needed.