Short answer

No cannabis product holds FDA approval for migraine. There is no standard dose. Published data comes from small trials, surveys, and state medical programs. A common start point is 1 mg to 2.5 mg THC by mouth, or one inhalation of 2 mg to 5 mg THC. Start at the low end and wait before adding more.

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What studies report

One observational study followed 2,032 adults who used cannabis for headache or migraine. Inhaled cannabis cut headache intensity by a median of 47.3%. Participants chose their own products and doses. The study had no placebo group, so it cannot prove cause.

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Lab work shows THC and CBD bind CB1 and CB2 receptors. CB1 receptors sit on trigeminal nerve pathways tied to migraine. That mechanism is a theory, not a proven treatment path.

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Dose ranges by route

  • Inhaled flower or vape: 2 mg to 5 mg THC per breath. Onset 2 to 10 minutes. Effect lasts 2 to 4 hours.
  • Oral oil, capsule, or edible: 1 mg to 2.5 mg THC at first. Onset 30 to 120 minutes. Effect lasts 4 to 8 hours. The liver converts THC to 11-hydroxy-THC, a stronger compound.
  • CBD alone: 25 mg to 200 mg per day in consumer products. No trial has set a migraine dose. Epidiolex, the FDA-approved CBD drug, is dosed at 10 mg/kg to 20 mg/kg per day for seizures.

Track these numbers

Keep a log. Date, route, mg THC, mg CBD, minutes to relief, pain score before and after on a 0 to 10 scale, and side effects. Neurologists measure success as a drop in migraine days per month. A 50% drop in monthly migraine days is the standard endpoint in trials.

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Risks

  • Cannabinoid hyperemesis syndrome. Daily use for months or years can cause severe vomiting. Hot showers give short relief. Stopping use is the treatment.
  • Drug interactions. CBD inhibits CYP2C19 and CYP3A4. It can raise blood levels of clobazam, warfarin, and some antidepressants.
  • Impairment. THC slows reaction time for 4 hours or more after inhalation. Do not drive.
  • Federal law. Cannabis is Schedule I. State medical programs set possession limits, not doses. Epidiolex is Schedule V.

Ask a clinician

  1. Which migraine drugs can I combine with cannabis?
  2. What is my monthly migraine day count?
  3. Do my current prescriptions interact with CBD?

Bring the log to the visit. Dose changes need data, and the cannabis dose response for migraine is not mapped.