Can you get medical cannabis for migraine or cluster headache in the UK?

Migraine and cluster headache are considered by UK specialists in selected cases, usually where the substantial standard toolkit has been exhausted. There is now one properly conducted randomised trial in acute migraine — and one specific risk, medication overuse headache, that makes frequent use of any acute treatment counterproductive.

Is migraine treated with medical cannabis in the UK?

Migraine and cluster headache are assessed in selected cases by private specialists. Neither is an NHS use and nothing is licensed for either. The bar here is higher than for many conditions, because headache medicine has a large and effective standard toolkit.

For migraine, that toolkit includes triptans for acute attacks, preventive medicines such as propranolol, topiramate, amitriptyline and candesartan, the newer CGRP monoclonal antibodies and gepants, and botulinum toxin for chronic migraine — several of which are NICE-recommended and NHS-funded. A specialist will want to know which of those you have properly tried.

Cluster headache is different again. High-flow oxygen and subcutaneous sumatriptan are highly effective acute treatments for many people, and verapamil is the standard preventive. There is no trial evidence for cannabis-based medicines in cluster headache at all, and specialists will normally want the standard treatments genuinely optimised first.

What the evidence actually shows

Until recently there was no randomised evidence in migraine at all. There is now one well-conducted trial, in acute treatment, and its result is positive — which is worth reporting accurately rather than either dismissing or overselling.

A randomised, double-blind, placebo-controlled crossover trial, published in Headache, had participants treat separate migraine attacks with four vaporised preparations: THC-dominant, CBD-dominant, combined THC and CBD, and placebo. The combined THC and CBD preparation was superior to placebo at two hours for pain relief (67.2% versus 46.6%), pain freedom (34.5% versus 15.5%) and freedom from the most bothersome symptom (60.3% versus 34.5%), with sustained effects at 24 hours and no serious adverse events. THC alone helped pain relief but not pain freedom; CBD alone was no better than placebo.

This is one trial, using vaporised flower in a controlled setting, testing acute treatment rather than prevention. It does not tell you whether daily use prevents attacks — and daily use of an acute treatment is precisely how medication overuse headache develops.

What a specialist will want to see

There is no UK list of qualifying conditions, so nothing here entitles you to a prescription. A specialist works through your history and decides whether a monitored trial is justified for you. For migraine and cluster headache they will typically look at:

• Your headache diagnosis: migraine with or without aura, chronic migraine, cluster headache, or something else
• How many headache days a month you have, and how many days you use acute medication
• Which preventives you have tried, at what doses, and for how long before judging them
• Whether CGRP treatments or botulinum toxin have been offered or considered
• Whether medication overuse headache has been ruled out — this changes the whole approach
• Triggers, sleep, and any co-occurring anxiety or depression

The general requirements — age, a documented diagnosis, the convention that two standard treatments have been tried, and access to your medical records — are covered in What are the requirements?

Risks and reasons a specialist may say no

The specific risk in headache is medication overuse headache: using any acute treatment on too many days a month can turn episodic headache into chronic daily headache. A treatment that helps each attack while increasing the number of attacks has made things worse.

Cannabis withdrawal can also cause headache, which creates an obvious trap for someone using it regularly. Beyond that, the usual profile applies: drowsiness, dizziness, impaired concentration, driving impairment from THC-containing products, and caution where there is any personal or family history of psychosis. Any new, changed or severe headache pattern needs medical assessment rather than self-treatment.

How medical cannabis is thought to help

Cannabis-based medicines act on the endocannabinoid system, a signalling network found throughout the brain, nervous system and blood vessels that helps regulate pain, mood, sleep and inflammation. That broad role is why these medicines are studied across such different conditions — but a plausible mechanism is not the same as proven benefit, and in headache the evidence is limited to a single acute-treatment trial.

The two most studied plant compounds behave very differently. THC is intoxicating and acts directly on cannabinoid receptors; cannabidiol (CBD) is not intoxicating and works more indirectly. In the one migraine trial it was the combination of THC and CBD that beat placebo, while CBD alone did not — which matters because THC brings its own side effects and driving implications. Our guides on the endocannabinoid system and THC and CBD explain the difference in more detail.

There is a specific catch in headache. Any acute treatment used too often can drive medication overuse headache, so a medicine that eases each attack while being used most days can quietly make the overall pattern worse. That risk shapes how, and how often, any treatment here is used.

What treatment involves in practice

Nothing is licensed for migraine or cluster headache, so any treatment here is unlicensed and carried on specialist responsibility with your informed consent. If a specialist decides a monitored trial is justified, it starts at a low dose and is increased slowly — titrated — while benefit is weighed against side effects and against how many days a month it is used.

Products are usually oils or capsules taken by mouth, which act more slowly and last longer, or dried flower for vaporising, which acts faster; smoking is never a medical route. In headache the frequency of use is watched as closely as the dose, precisely because of medication overuse headache. How the format and dose are chosen is set out in how a dose is decided and adjusted and how cannabis-based medicines are taken.

Follow-up reviews check how you are responding and whether side effects are tolerable, and the plan is adjusted — or stopped — accordingly. Benefit is judged over weeks using a headache diary rather than a single attack, and how long cannabis medicines take to work explains why. Treatment that is not clearly helping is stopped rather than continued indefinitely, and standard headache treatments continue to be optimised alongside.

Questions worth asking your specialist

A good assessment is a two-way conversation. Whether treatment turns out to suit you or not, these are sensible questions to bring, alongside the practical guides on driving, work and drug testing, and travelling abroad:

• Have we ruled out medication overuse headache before considering another acute treatment?
• Have the standard preventives and, where relevant, CGRP treatments been properly tried?
• How many days a month could I safely use this, and how will we track that?
• How will the THC component affect my driving and concentration?
• At what point would we agree the treatment is not helping and stop it?

If you want to take this further

The useful next step is a proper assessment, not a better list. Gather your diagnosis, the treatments you have already tried and what happened with each, and your current medicines — that is what a specialist needs in order to give you a straight answer.

The consultation itself, and what happens after it, is set out in What is the process to get a medical cannabis prescription? If migraine and cluster headache is not the only thing you are being treated for, say so early: other conditions and other medicines change the assessment.

Patient guide · Written by the Flora House editorial team · Last reviewed: 7 October 2026