CBD vs THC law in the UK: What’s legal, and what’s not

What is CBD vs THC, from a legal perspective, in the UK? 

It’s a question that’s become increasingly important in recent years. And while plenty has been discussed, debated, and even legislated, clear answers are still surprisingly hard to come by.

CBD is, by most metrics, legal in the UK. 

You’ll find it on pharmacy shelves, in supermarket wellness aisles, maybe even swirling around your elderly neighbour’s late-night brew. THC, meanwhile, remains cloaked in something of a legal fog. It is often mentioned in the same breath as cannabis, but treated very differently by the law. 

The trouble is, most people don’t quite know where the lines are drawn.

So…

• What makes CBD legal in the UK, and THC a controlled substance? 

• How can one be so easily available over the counter, while the other requires a specialist doctor to write a prescription? 

• And where does legal UK medical cannabis treatment (which prescribable products often contain both) fit into this slightly wonky jigsaw?

We’re here to help. 

To give clear, concise answers to the more pressing questions regarding CBD vs THC law in the UK. The rules, the reasoning, and what it all means for people looking to access legal UK medical cannabis treatment options the right way.

CBD is legal in the UK, but it depends on how it’s made

CBD is openly available throughout the UK, but certain requirements have to be met by producers and retailers. 

First up, the CBD in all over-the-counter UK CBD products has to come from EU-approved industrial hemp plants. The source plants must produce no more than 0.2% THC. That’s the simple part.

Next, the final CBD product must contain no more than 0.2%THC, or 1 mg per product container, to be legally sold over the counter in the UK. This threshold has been the accepted interpretation in the UK for years, although there have been recent discussions about reducing it to zero detectable THC. No formal change has been confirmed, but the direction of travel suggests tighter limits may be coming soon.

CBD products that are intended for ingestion (oils, capsules, drinks, edibles - the list goes on) must also meet the requirements of the FSA’s Novel Food regulations for CBD products. This means the company must first submit a valid application, including safety data and ingredient details. 

What is industrial hemp, and how does it differ from medical cannabis plants?

• Industrial hemp is one part of the Cannabis sativa L. genus that naturally produces very low levels of THC. Historically, it was grown for its fibre and seeds (it was one of the most important crops in the UK up until about a century ago), but in recent years, there has been a shift toward cultivating it for non-intoxicating cannabinoid content, particularly CBD. 
• Medical cannabis plants (also in the Cannabis sativa L. family), by contrast, are bred to produce higher levels of THC and are tightly controlled under UK drug laws.

It’s also worth noting that CBD extracted from high-THC cannabis, rather than industrial hemp, is illegal for OTC (over the counter) sale. And when it comes to extracts, CBD isolate, broad spectrum, and full spectrum all sit slightly differently in the regulatory landscape, depending on their cannabinoid profile.

Topical products like CBD creams and cosmetics fall under different regulations and aren't the focus of this article, but the legal principle is the same: source, THC content, and compliance all matter.

CBD is legal for OTC sale in the UK if:

• It is derived from EU-approved industrial hemp

• The final product contains no more than 0.2% THC

• It is listed on the FSA’s Novel Food authorisation register
• It is correctly labelled and does not make medical claims

THC is classified as a controlled substance in the UK

THC is where the legal landscape starts to tighten. While CBD floats its way to the shelves of chemists, high street boutiques, and supermarkets, THC sits shackled on the other side of the legal line. 

Without a legal prescription from a specialist doctor listed on the GMC Specialist Registry, the production, consumption, and sale of THC (and any products containing more than 0.2% of it) is completely illegal. 

When is THC legal in the UK?

THC is only legal if you’ve been prescribed it by a specialist doctor. That usually means going through a private clinic, since NHS access is rare and highly restricted. But once prescribed, you’re covered. Possession and use are fully legal, as long as you abide by the terms of your prescription and carry it for personal medical use.

The majority of medical cannabis products in the UK are THC-dominant, though many also include some CBD. Balanced options (say 10% THC - 10% CBD) are also becoming more common, and you’ll also find options with more CBD than THC. 

Why is THC still illegal in the UK without a prescription?

THC is still listed as a controlled drug in the UK, plain and simple. It is a Schedule 2 substance under the Misuse of Drugs Regulations. While medical cannabis became a legal treatment option back in November 2018, it is only in the past couple of years that prescriptions have become more common, and even then, mostly through private clinics.

The law treats THC as something that needs to be tightly controlled. Legislators now agree that cannabis has recognised medical potential, but they have not stepped back from the belief that it also comes with a risk of harm or dependency if used without guidance. 

That is why it is illegal to sell, possess, or import THC-containing products without a prescription or special licence.

This includes the growing number of so-called grey market products. Vape cartridges, edibles, and oils that claim to contain THC can be found advertised online, but these are illegal and totally unregulated. Take caution, you have no way of knowing what you are actually buying.

Regulation and clinical oversight make medical cannabis a far safer option for patients. Prescribed products are tested, standardised, dispensed with specialist consideration, and all medical cannabis patients in the UK are legally required to attend regular follow-up consultations to ensure ongoing therapeutic effectiveness and safety. 

The same cannot be said for anything purchased through any other route.

CBD vs THC: Legal comparison in the UK

If your store-bought CBD isn’t working for you, there may be another solution…

Over-the-counter CBD works fine for some, but not for everyone. If you're dealing with chronic pain, anxiety, sleep issues, or other long-term health issues, the low-strength (often not what is stated on the label) oils and gummies found on high street shelves may not be enough to make a difference.

With a valid prescription, UK patients can legally access medical cannabis products that offer far more flexibility. These include CBD-dominant formats with higher concentrations, as well as options that contain THC, prescribed in the right balance for your needs. 

Unlike shop-bought CBD, these treatments are held to a much higher standard. Every stage is regulated, from how the plants are grown to how the medicine is prescribed. Nothing reaches the patient without passing clinical oversight, safety checks, and formal quality controls.

At Releaf, we provide supported, legal, and consistent access to medical cannabis to patients who truly need it. Our doctors work alongside the patient to personalise treatment plans, including products that combine CBD and THC in varying ratios, depending on what works for you. 

Whether you're new to cannabis or have already tried CBD with limited success, our approach puts clinical oversight and patient safety first. If you're not seeing results from high street CBD, there may be a more effective option.