6 min read
Hannah Clark
The wave of legal medical cannabis reached UK shores on the 1st of November 2018, bringing with it hope for patients who have tried conventional pharmaceutical treatment options but found little relief.
For the majority of people who have not tried cannabis before, the idea of taking it for therapeutic purposes comes with a few key questions that need answering before they can feel comfortable and confident.
One of the most often-asked questions we hear is, "Will I get high when I take medical cannabis?".
Let's find out…
Key takeaways
Contents
While some medical cannabis treatments do contain THC (the compound that causes feeling ‘high’), that feeling is not the intention of the treatment. It’s actually considered a side effect, and prescribing specialists use methods to minimise side effects where possible.
Both THC and CBD are cannabinoids found in the cannabis plant, but they work in very different ways.
While THC administration can cause that feeling of being 'high', CBD is totally non-intoxicating. It may help you relax, but should not impair your ability to function.
Both CBD and THC-based treatments may be prescribed, but it all depends on the patient’s condition and the specific medication prescribed. Some conditions, such as chronic pain or multiple sclerosis, may require a certain percentage of THC to be present in the medication for it to be effective.
However, for other health issues like anxiety or epilepsy, CBD-based treatment options that contain zero THC may be the better option.
Every treatment plan varies by patient which makes it tricky to sum up exactly what it’s like starting out, but we’ll try.
If you qualify, your prescribing specialist will talk you through your proposed treatment plan. They’ll determine the form of medication, the strength, and your starting dose. This is the ideal time to raise any concerns you have about your treatment, and whether feeling ‘high’ is a side effect you may experience.
Once your first prescription arrives, take it exactly as instructed by your prescribing specialist.
You’ll likely have been started on a low dose (relative to your condition) to see how you respond to the medication and what effect it has on you. The idea is always to start low and go slow. Your specialist can adjust your dosage as needed until that sweet spot is found.
Your follow-up consultations are there to help monitor and manage your treatment. Your specialist will want to hear how you’ve found the treatment, whether your symptoms have improved, and any side effects you’ve experienced.
This specialist oversight means your treatment can be tailored to you and your needs. If you are prescribed a medicine containing THC, they will work to minimise side effects over all, including the feeling of being ‘high’.
Most notable is their legal status, as recreational or ‘street’ cannabis is illegal, and cannabis-based products for medicinal use have been legal for specialist doctors to prescribe since 2018.
This key difference between recreational and medical cannabis then has a roll-on effect that impacts how it’s cultivated, regulated, tested and distributed.
CBPMs are subject to stringent testing to determine the cannabinoid makeup and are prescribed by a specialist doctor who knows exactly what you are taking.
Recreational cannabis has no regulation or oversight, so there is no way to know how or where it was grown, by whom, what chemicals might have been used, or what is in it.
As with any prescribed medication, there is the possibility of side effects with medical cannabis treatment in some patients. Common side effects tend to be mild and pass quickly, but your specialist will also work to minimise them where possible.
Speaking to your prescribing specialist about any side effects you experience is part of the follow-up process and they can adjust your treatment where needed.
Yes, you can build up a tolerance, the same as you can to other medications with regular or daily use.
Preventing too quick a tolerance build up is part of what your specialist is there for, managing your treatment to ensure you reach the desired result by incorporating planned medication breaks.
Contact your prescribing team as soon as possible if you experience any strong, unexpected or rare side effects, or call 999 in an emergency.
Do not drive if you are in any way impaired by your medication, and you can report any side effects through the MHRA’s Yellow Card scheme.
It depends on how the treatment affects you, but the most important thing to remember is driving while impaired by any prescription medicine is an offence.
While CBD is non-intoxicating, it may cause drowsiness in some individuals, which counts as impairment. As mentioned above, THC treatments may make some patients feel ‘high’ or otherwise impaired, meaning they are not safe to drive.
It is down to the patient to recognise how their medication affects them and whether they are safe to drive. A valid prescription does not override the law.
It depends on what you mean by ‘strong’. For most patients, cannabis strength is normally referring to THC% with higher percentages being more associated with side effects like feeling “high”
If we are only looking at THC levels alone, then the prescribed flower starts low at 7% and tops out at 29%, with cultivars testing THC levels over 20% considered stronger or high potency.
However, there is more to medical cannabis flower than THC, so there is a lot more to consider when trying to determine ‘strength’.
Your prescribing specialist is always there to listen to your concerns. They will be able to guide you towards the most appropriate treatment for your specific condition.
If you are prescribed a treatment option that contains THC, your doctor will help you find the right dosage to minimise any potential intoxicating effects. Most often, you will be directed to start with a low dose, gradually increasing it over time until you feel the desired therapeutic effects without the feeling of being 'high'.
At Releaf, we work with a world-class clinical team of medical cannabis specialists in the UK. By focusing on tailoring individual treatment plans, our doctors ensure that our patients receive as much care and support for their unique health conditions as possible.
If you are interested in finding out if you qualify for medical cannabis treatment, and have 2 minutes to spare, check out our free medical cannabis eligibility checker!
Releaf - Redefining healthcare
It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.
As of 12 August 2026, Releaf has the highest Trustpilot score, 4.8 from 9,598 reviews. Curaleaf received an overall CQC rating of ‘Good’, Alternaleaf advertises appointments for £29, while Mamedica's £200 Access Scheme is designed to potentially reduce long-term clinic costs. The right clinic for you will depend on what you value most from a clinic, but comparing the full treatment experience, rather than a single headline figure, is essential.
On the 7th July 2026, Releaf became the first medical cannabis clinic in the world to become B Corp certified. Verified by the non-profit B Lab, the certification sets in stone that Releaf is meeting the highest standard of social and environmental performance, transparency, and accountability, and has made a commitment to continue improving the way we serve not only our patients, but also our team, and the wider community.
We are proud to announce a new partnership between Releaf and brainstrust, the UK charity supporting people affected by a brain tumour. Together, we want to make sure that anyone living with a brain tumour has access to compassionate, expert care through the most trusted medical cannabis clinic in the UK. Here is what the partnership means and how patients currently in treatment can get in touch.
"Since starting my treatment plan with Releaf, I’m genuinely shocked at how well it has worked."Chloe Durrington, Releaf patient
