The short answer
The FDA has not approved cannabis or any cannabis product for migraine treatment or prevention. Epidiolex (CBD) is approved for three seizure disorders. Dronabinol and nabilone are approved for chemotherapy-induced nausea. Migraine is not on that list.
Reddit threads about migraine and cannabis show mixed reports. Some users write that 2.5 mg to 10 mg of THC at the first sign of an attack cuts pain and nausea. Other users write that cannabis triggers attacks, causes rebound headaches, or does nothing.
What Reddit users say
Recurring claims in r/migraine and r/medicalcannabis:
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- Inhaled THC at aura onset. Users report relief in 10 to 30 minutes.
- High-CBD products with little THC. Reports range from help to no effect.
- Indica strains at night for sleep, with fewer morning attacks.
- Edibles for long attacks. Users report a window of 4 to 8 hours.
- Worsening. Some users report a headache the day after use, or more attacks during heavy use.
These are anecdotes. Reddit users do not report dose, strain lab results, or placebo use. Threads favor people who got a result worth posting.
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What studies show
Clinical evidence is thin. Reviews index few randomized controlled trials of cannabinoids for migraine. Most data comes from surveys and retrospective chart reviews, which rely on self-report and have no control group.
Chart reviews of medical cannabis patients report drops in monthly migraine days. Survey data point the same direction. Neither design separates cannabis from expectation, rest, or changes in other drugs.
THC, CBD, and product forms
- Inhaled THC: effects start in seconds to minutes, last 2 to 4 hours.
- Oral THC: bioavailability 4% to 12%, onset 30 to 120 minutes, effects last 6 to 8 hours. Dose accuracy is poor in homemade edibles.
- CBD alone: trial data for migraine is small. Epidiolex dosing does not transfer to over-the-counter CBD.
Terpene and strain claims come from user reports and lab marketing, not from migraine trials.
Risks
- Cannabinoid hyperemesis syndrome: heavy long-term use, cycles of vomiting, hot showers for relief.
- Medication overuse headache: daily use of any acute treatment can raise attack frequency.
- Drug interactions: cannabis affects the CYP3A4 and CYP2C9 enzymes, which process some blood thinners, antidepressants, and seizure drugs.
- Cardiovascular: the American Heart Association lists cannabis smoke and vapor as risks for heart and lung disease.
Before you try it
Keep a headache diary with date, onset, dose, form, and pain score. Bring it to a neurologist. Triptans, gepants, and beta blockers have trial data for migraine. Cannabis does not. Check state program rules, because migraine is a qualifying condition in some states and not in others.