Use our chat feature to speak with one of our expert consultants who can help you identify if medical cannabis can help you.
7 min read
Sam North
The first question that most new patients have (often before even reaching out to a medical cannabis clinic) is -
While cannabis-based treatment options have been shown to offer patients a very favourable safety profile with a wide range of therapeutic benefits - like almost all medical options, there are side effects to consider.
Some common medical cannabis side effects include slight dizziness, a dry mouth, changes in how hungry they feel, a shift in mood, raised blood pressure, racing heartbeat, and higher anxiety levels.
While a few of these side effects do sound concerning, they are most often on the milder side and generally subside quickly.
If you experience any unwanted side effects from medical cannabis options, keep in mind that they can usually be managed and minimised through fine-tuning your dosage and proper strain or product selection.
There is a bit more to this, so let's dive right in.
Both THC and CBD are classed as cannabinoids, and both offer patients a natural treatment solution. However, they do differ in some specific ways, with side effects being one of them.
Products containing more than 0.2% THC (or 1 mg per container) are only legally available in the UK if a specialist doctor prescribes them.
THC is the major psychoactive component produced by Cannabis sativa L. plants, and while it has been shown through rigorous research to be an effective and safe therapeutic option for the overwhelming majority of patients, it does come with some side effects to be aware of.
The more common side effects of medical cannabis containing THC include:
High doses of THC can also induce feelings of anxiety, paranoia, or panic in some people - but, when prescribed through a specialist and the dosage is monitored, these side effects can generally be avoided.
Medical cannabis products with higher levels of CBD and low or no THC content have also shown to be very safe and come with slightly less risk than those with high THC percentages.
CBD products are allowed to be sold OTC in the UK, as long as each container has no more than 1 mg of THC.
The more common side effects of medical cannabis containing CBD include:
Some patients may also experience changes in their mood, but these are generally milder than those experienced with THC administration.
They can - it depends on the route of administration.
In the UK, medical cannabis options are available in multiple forms, including oils, capsules, sprays, and dried flower.
Medical cannabis oils are usually prescribed for sublingual (under the tongue) administration, but may also be taken orally.
The National Institute for Health and Care Excellence (NICE) considers both routes to be effective and safe therapeutic options. However, both sublingual and oral administration can lead to the oil reaching the digestive tract, which can cause unwanted side effects such as nausea or gastrointestinal discomfort for some patients.
In the vast majority of cases, yes, medical cannabis side effects can be effectively managed and sometimes totally mitigated.
Cannabis-based therapy is a very individual process, and the side effects that patients experience can be greatly impacted by things like their unique body composition, the specific treatment option being used, and how long they have been using it.
There is often a short 'trial-and-error' period when patients first start with cannabis-based treatment options. Everyone responds differently, so finding the right dosage and administration method can take a little time.
The short answer is yes - in fact, titration is the most common approach by medical professionals when prescribing cannabis-based therapies.
Titration is a process of gradually increasing the dosage size until the 'sweet-spot' is found. This allows your body to slowly get used to the treatment, which helps minimise the risk of any unwanted medical cannabis side effects popping up.
High doses of THC can also induce feelings of anxiety, paranoia, or panic in some individuals, but when prescribed through a specialist and the dosage is monitored, these side effects can generally be avoided.
Always follow the dosing and administration instructions of your prescribing specialist. Most new patients will be instructed to titrate their cannabis-based medication, which involves starting with a low dose and slowly increasing the dose size until the desired therapeutic effect is achieved.
Yes, both CBD and medical cannabis products containing THC have been shown to have a positive impact on anxiety symptoms. Read more over at our medical cannabis for anxiety page.
While medical cannabis offers a natural, generally safe therapeutic solution, there can be some issues with heavy, prolonged, unsupervised use. This is why it's essential to always follow the advice and guidance of your prescribing specialist, and to report back to them any sudden changes or reactions.
The potential side effects of prolonged, unsupervised cannabis use can include memory issues, mood changes, changes in appetite, and cognitive impairment.
Again, always follow the guidance of your doctor and never self-medicate.
While exceedingly rare, there can be a few severe reactions to medical cannabis. Some of these can include:
Anyone with a history of psychosis or severe mental health issues should speak to their current clinical team before reaching out to a medical cannabis specialist. The specialist you choose to reach out to should have experience prescribing medical cannabis options to people with similar conditions.
Yes, some patients may experience withdrawal issues. However, your specialist will help to devise a treatment plan that will minimise any chance of withdrawal issues or side effects.
Cannabis withdrawal symptoms usually pass after 3 to 4 days and can include:
Like almost all medical treatment options, cannabis-based therapies may come with a few side effects. These side effects are usually very mild, and when prescribed and monitored by a specialist, most medical cannabis side effects can be effectively managed or avoided altogether.
If medical cannabis is something you are considering, feel free to head over to the Releaf eligibility checker. It takes less than 30 seconds, and you will instantly be advised whether you are potentially eligible for a UK medical cannabis prescription.
To learn more, check out our education and blog sections, or feel free to reach out to our team at any time.
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.
Get comprehensive care, convenience, and confidence with an all-in-one treatment plan.
Am I eligible?Sam North, a seasoned writer with over five years' experience and expertise in medicinal cannabis, brings clarity to complex concepts, focusing on education and informed use.
All of our articles are written by medical cannabis experts, guided by strict sourcing guidelines, and reference peer-reviewed studies and credible academic research. Our expert clinical team and compliance specialists provide valuable insights to ensure accuracy when required. Learn more in our editorial policy.
Need more help?
Along with adapting to a whole new treatment option, patients just starting with medical cannabis treatment can sometimes find themselves feeling a little inundated by the terminology, acronyms, and jargon that accompany their treatment plan. One of the key terms for new patients to get their head around is MDT: Multidisciplinary Team.
Sam North
We all suffer from bloating, cramping, and constipation from time to time, but certain conditions and medications can make these symptoms particularly problematic.
Emily Ledger
Explore the potential of medical cannabis in 2025 as an alternative healthcare option in the UK. Learn how Releaf helps patients address health concerns like anxiety, chronic pain, and more with personalised, patient-centred treatment plans. Discover the benefits, conditions eligible for treatment, and how to take the first step toward a healthier you this New Year.
Lucy MacKinnon
