BlogWhat is prescribed cannabis oil?

What is prescribed cannabis oil?

13 min read

Sam North

What is prescribed cannabis oil

In today's article, we are going to put a spotlight on all the medical cannabis oil options that are now legally prescribable here in the UK and take a close look at how they may be able to aid patients in managing symptoms relating to a huge range of health conditions.


In the Western world, the idea of alternative or complementary plant-based medicinal options has long been met with scepticism or outright dismissal. Images of ancient herbalists or shelves stacked with roots and leaves come to mind, and with how healthcare is treated in modern society, it's not hard to see why people might be hesitant.

But as the years creep by and pharmaceutical options continue to come up short in addressing certain health concerns, patients are increasingly searching for options they may have never considered.

Medical cannabis oils are among the newest legal options for patients to contemplate, but it is still shrouded in a cloud of misinformation and misunderstanding, at least to a certain extent.

What is cannabis oil?

Cannabis oil refers to any oil (and sometimes tinctures) that contains the active compounds produced by cannabis sativa L. plants. This includes not just cannabinoids (THC, CBD, CBG, etc.) but also terpenes, flavonoids, and other plant-derived compounds.

There is no single cannabis oil. The term encompasses a full range of various products with varying levels and ratios of cannabinoids. Some are legal for "over-the-counter" sale here in the UK, while others require a prescription.

Isn't cannabis oil just another term for medical cannabis?

Not quite.

Medical cannabis (or medical marijuana - more commonly used in the USA) is the term used to cover all of the different forms of cannabis that have been found to have therapeutic value and are legally offered through prescription. Cannabis oil is just one of those forms, but it's not the same as dried cannabis flower or other options.

How is medical cannabis oil made?

The first step is to grow the source plant. Medical cannabis plants are essentially the same plants that are grown for recreational use, but the regulatory processes that govern medical cannabis require them to be grown under very stringent guidelines to ensure consistent quality and safety.

Once the crop has been harvested, the trichomes are extracted from the flowers using a variety of methods. The trichomes are the crystal-like structures on the plant's surface (the flowers and "sugar leaves"), where all the cannabinoids, terpenes, and flavonoids are produced.

Cannabis oil extraction methods are broken down into two main categories.

Solvent extraction

Solvent extraction is the most commonly used method of extracting cannabinoids from cannabis plants. This involves using a solvent - typically ethanol or CO2 - to separate the trichomes from the harvested plant material.

In the medical cannabis sphere, almost all prescribable oil options are made through the CO2 supercritical extraction process, as it is deemed to be the safest and most effective method.

Non-solvent extraction

Non-solvent extractions are much less common in the medical scene. It refers to any extraction method that doesn't involve a solvent, such as using heat and pressure or water-based processes. These methods are not used as often for medical products as they are less efficient, harder to scale, or may produce less potent end products.

What are the different types of cannabis oil available in the UK?

Apart from the different extraction methods, there are three main types of cannabis oil available in the UK for medical application.

Full-spectrum cannabis oil

Full-spectrum oils contain all the compounds produced by the source plant, including the full range and potency of cannabinoids, terpenes, and flavonoids. This is seen as a more "natural" option for patients, as it mimics the effects of consuming the whole plant. Full-spectrum oils also offer what is referred to as the "entourage effect", which we will explain a little further down.

Broad-spectrum cannabis oil

Broad-spectrum oils are almost the same as full-spectrum oils, with one major caveat - they are made from a source plant containing elevated levels of THC, but all of the THC has been removed from the final product. Here in the UK, most cannabis oil options containing less than 0.2% THC are legal for over-the-counter sale. However, as per the NHS guidelines, oils containing any THC content above 0.2% can only be legally sold with a prescription.

Isolate-based cannabis oil

Isolate-based oils are the purest form of cannabis oil, containing only a single cannabinoid - typically CBD or THC. All other compounds have been removed during the extraction process. Isolates are often used in medical settings when a specific cannabinoid is desired for therapeutic purposes.

So, what is the entourage effect, and does it matter?

The "entourage effect" is one of the more interesting aspects of cannabis oil application. It refers to the idea that when you consume the full range of cannabinoids, terpenes, and other compounds together, they have a synergistic effect that enhances the overall medical benefits.

Some studies suggest that isolates may not be as effective as full-spectrum options due to this effect, but the jury is still out. Regardless, many patients prefer to have access to all the beneficial compounds together in their cannabis oil.

We expect to see further research and more concrete results on the entourage effect as medical cannabis becomes more widely accepted and studied. In the meantime, it's up to patients and their prescribing specialists to decide which type of oil is best for their individual needs.

What is the difference between prescribable and over-the-counter cannabis oil options?

There is one major factor that separates prescribable and over-the-counter cannabis oil options in the UK - THC content.

The dichotomy of THC and CBD

THC, or delta-9 tetrahydrocannabinol, is the main psychoactive compound produced by cannabis plants. It's what gives users the euphoric "high" associated with recreational use. However, it also has many therapeutic benefits, including pain relief, reducing nausea, increasing appetite, and helping with anxiety disorders.

CBD, or cannabidiol, is the second major cannabinoid produced by cannabis and the one more often publicly associated with therapeutic benefits. This is mostly due to the fact that CBD is totally non-psychoactive, meaning it does not cause any sort of 'high' when consumed.

For any cannabis oil to be legally obtained over the counter in the UK, it must contain no more than 0.2% THC, and come from a source plant that produces less than 0.2% THC. Cannabis oils with any higher levels of THC are still classified as controlled substances under the Misuse of Drugs Act and can only be legally obtained with a prescription.

THC or CBD: which one is better for medical application?

The answer to this question depends on the specific condition being treated and the individual patient's needs. Some conditions may respond better to higher THC levels, while others may benefit more from CBD

Both CBD and THC offer significant medical benefits, but they work differently. 

This is why different ratios of THC to CBD can produce vastly different results for patients, and why there is such a huge range of medical cannabis oil options available on the market. When it comes to cannabis oil - or any medical cannabis product - there is no one-size-fits-all solution. Patients must work with their doctors to find the best option for their individual needs and conditions.

Why choose cannabis oil?

For many patients with chronic, treatment-resistant conditions, cannabis oil presents an alternative that, in some cases, has shown greater efficacy than traditional medications. The conditions that cannabis oil treatment can be prescribed for are diverse, but some of the most significant categories include chronic pain, epilepsy, arthritis, gastrointestinal issues, and mental health concerns. 

Cannabis oils also offer a wider range of administration methods than some of the other cannabis-based products for medicinal use (CBPMs), and depending on the route of administration, the onset and duration of effects can be more manageable. Furthermore, many patients prefer cannabis oil as a treatment option because it is non-invasive and does not require any inhalation, which may have negative connotations for some individuals.

How should you take your prescribed cannabis oil?

Administering cannabis oil is about as straightforward as it comes. Most often, the specialist in charge of your case will direct you to take your prescribed cannabis oil sublingually.


Sublingual administration refers to placing the medication under your tongue and holding it there for a short period, usually around one minute. This allows the oil to pass directly into the bloodstream, bypassing the digestive tract. When a medication is taken orally and has to pass through the digestive system, a significant portion can get broken down and rendered ineffective.

Sublingual administration allows for greater bioavailability of the medication, making it more potent and effective and allowing for a faster onset of effects.

Depending on your specific circumstances, you may be advised to take your oil sublingually, orally, as a topical application, or possibly even through a vaporiser.

What is the normal dosage size of cannabis oil?

There really is no standard dosage size of cannabis oil. In fact, there is no "one-size-fits-all" dose for any CBPM, and it is up to the prescribing specialist to determine what dosage size will work best for your unique needs.

The dosage size will depend on several factors, such as your age, weight, metabolism, medical condition being treated, and the type of cannabis oil you are using. It is essential to follow your doctor's instructions carefully and not exceed the recommended dose without consulting them first.

Titrating cannabis oil for optimal results

One of the challenges with prescribing cannabis oil is finding the right dosage for each patient. Most specialists will advise you to take a small dose to begin with, and then slowly increase the dosage size over a period of days or weeks until the desired effects are achieved. 

This process is known as titration and is crucial for finding the optimal dosage size while avoiding any unwanted side effects.

Will medicated cannabis oil cure my condition?

Misconceptions around cannabis oil (and cannabis medicine more generally) are as rife as with the plant itself. Cannabis has gone through more than a century of demonisation, and while the views of the general public are slowly beginning to shift, there are still many who believe that cannabis is not a legal medical option.

The reality is that while cannabis oil may offer significant relief for some patients, it is not a straight-out cure for any condition.

It's essential to align the conversation with its medicinal roles and available evidence-based treatments. Cannabis oil isn't a 'miracle cure-all', but it is a potentially potent option in the medicinal toolkit, and especially valuable when traditional therapies fall short.

Think of cannabis-based medicine as one of many treatment options available, and work with your doctor to determine if it is the right choice for you.

How safe is medical cannabis oil?

Cannabis oil is considered to be an extremely safe therapeutic option.

Some concerns revolve around addiction potential, which is mostly associated with higher THC products, as they do have the power to produce an intoxicating and euphoric effect. In the UK, strict regulations are in place for prescribed cannabis, protecting against misuse and ensuring the focus is on patient wellbeing.

Cannabis oil, when administered as part of a comprehensive care plan under the supervision of a specialist, offers a promising treatment option with a notably lower risk profile than many of the pharmaceutical options currently available. Its implementation is associated with lower rates of opioid use, which is a significant concern in the UK and worldwide.

How do you receive a prescription for cannabis oil in the UK?

In the UK, medical cannabis can only be prescribed by a specialist doctor. Navigating this process can be daunting, especially for patients new to cannabis medicine. Still, the legal framework is in place to ensure that those who could benefit from medicinal cannabis can access it safely and within the bounds of the law.

There are two main routes to receiving a medical cannabis prescription in the UK:

  • Through the NHS: Currently, the NHS will only prescribe CBPMs for three specific health issues -  two types of rare epilepsy, multiple sclerosis, and chemotherapy-induced nausea and vomiting.
  • Through a private cannabis clinic: If your condition does not fall under the NHS guidelines, you can seek out a private consultation with a specialist doctor working with a clinic like us here at Releaf, who can prescribe cannabis oil if you have already tried two other treatments and if they deem it appropriate for your treatment plan.

More than 99% of prescriptions in the UK come through private clinics. If you want to learn more about the process, we are here to help.

FAQs: Common questions new patients have about cannabis oil

Will I get high on prescribed cannabis oil?

In the UK, prescribed cannabis oils are low in THC, the compound responsible for the 'high'. They are formulations primed for therapeutic use without associated psychoactive effects.

Can I drive after using cannabis oil?

The legalities around driving under the influence of cannabis apply, and it's critical to adhere to these guidelines. Always discuss this with your prescribing doctor if in doubt.

What are the side effects?

Common side effects of cannabis oil can include drowsiness, dizziness, and appetite changes. The risks are generally low, but it's crucial to communicate with your prescribing specialist to manage any unexpected reactions.

What should I tell my employer about cannabis oil use?

That's totally up to you. Medical cannabis is legal in the UK, and as long as you access it through the appropriate channels, there should be no negative consequences. But keep in mind that if you work a job where drug testing is required, you may have issues.

Final thoughts

Navigating the world of prescribed cannabis oil is a personal medical choice. It requires dialogues with healthcare professionals and a commitment to understanding the process and expectations. For some, it marks the cusp of a newfound, more manageable health reality. For others, it may still hold a whisper of uncertainty.

For those at the start of this conversation, we are here to help. Releaf specialises in creating personalised, tailored cannabis treatment plans. Our expert team can guide you through the process, from initial consultation to potentially obtaining a prescription and ongoing support. We understand that medical cannabis may feel unfamiliar or overwhelming, but we are committed to providing compassionate, reliable care to help you achieve the best possible outcomes.

To find out more, check out our education section or see if you're eligible with our medical cannabis eligibility checker

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.

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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.

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