What is the difference between CBD and THC?

When people hear buzzwords like CBD (short for cannabidiol) or THC (short for tetrahydrocannabinol) they instantly think about smoking a joint and getting high. The association of CBD with the murkiness of getting high is heavily ingrained in society. It will take years of educating people to change their mindset. Even though both compounds come from the same genus, Cannabis sativa, there is a big difference between CBD and THC.

The genus Cannabis sativa includes two plant types: Hemp and marijuana. The marijuana plant can yield CBD and THC. THC is the compound that gets you high though and is a controlled drug. Herein also lies the problem.

Being a controlled drug means it is illegal in most countries in the world. It is not allowed to grow marijuana plants, extract the CBD and destroy the rest of the plant with its THC. Hence, an alternative had to be found. This alternative came in the form of the hemp plant.

Hemp can yield CBD but not THC. Hemp plants have less than 0.3% or 0.2% of THC content within them. They also yield a higher amount of CBD than marijuana plants (up to 20% of the plant).

If you want to grow hemp in the UK you need a hemp growing licence. The plants you want to grow need to be from approved seed types and the THC content is not allowed to exceed 0.2%.

CBD and THC have the same chemical formula. They both contain 21 carbon atoms, 30 hydrogen atoms, and two oxygen atoms. The only difference is in the structure of the atoms. There are more than 100 other cannabinoids found in cannabis plants. But CBD and THC are the most common ones.

Cannabis plant showing formulas of CBD and THC

Here is an overview of the difference between CBD and THC.

A closer look at CBD

CBD is a non-psychoactive compound. That means you will not feel any euphoria after ingesting it. According to a report from the World Health Organisation (WHO), CBD is a well-tolerated substance. To date, there are no public health-related problems associated with the use of CBD.

When CBD enters your body it interacts with your endocannabinoid system. If you are unfamiliar with the endocannabinoid system, here is an overview. There are two main receptors in that system called CB1 and CB2.

CBD interacts mainly with CB2 receptors which are found in your immune and gastrointestinal system. Albeit in a lower density. If you are taking CBD to target your immune system (for arthritis or inflammation) you now know that CB2 receptors are at work.

It has also been discovered that CBD limits the effect of THC by modifying CB1 receptors. Such modification means THC can’t bind to the receptor as easily. As a result, you won’t get as high when you take CBD in combination with THC compared to taking THC on its own.

A closer look at THC

THC is the “evil twin” of CBD giving you the psychoactive high effect. When you smoke THC, it goes into your bloodstream and into your brain within seconds. THC has a similar shape to anandamide which is an endocannabinoid produced by your body. Due to that shape THC binds mainly to CB1 receptors which are found in the brain and the nervous system.

CB1 receptors regulate memory, cognition, movement, sensory perceptions and even time perception. As THC binds to CB1 receptors, your brain thinks it’s anandamide that’s binding to the receptor. As a result, it releases more dopamine into your bloodstream.

The problem is that THC cannot be broken down as quickly as anandamide and sticks around for longer. In contrast to THC, CBD is bad at activating CB1 receptors hence it doesn’t give you that high effect.

By binding to CB1 receptors THC changes functions regulated by those receptors. The sum of those changes combined is the psychoactive feeling of being high that you experience.

THC also activates your reward circuits in your brain. It makes you feel good and plays a major role in giving you that feeling of euphoria.

Man jumping outside full of euphoria


At the end of this blog post, you can find a summary table with all the benefits you might experience when taking CBD or THC. Both compounds cover almost the same benefits apart from a few that THC is not good for. Those are depression, seizures and psychosis.

Depending on the dosage, THC will either help you reduce your anxiety or amplify it. Care needs to be taken with anxiety as well. More details on the benefits of CBD and why you shouldn’t miss out on them can be found here.

Although THC can help with anxiety in low doses it can be counter-productive in higher doses. Too much THC will increase your existing anxiety. Or it will induce new anxiety feelings. It does so by increasing your heart rate. This shows how important dose regulation is when it comes to THC.

Whilst CBD may reduce depressive feelings, THC can make them worse over time. Scientific evidence shows that heavy marijuana use is associated with

  • depression
  • anxiety
  • personality disorders

But what is a low dosage? According to research a few puffs when smoking the substance was enough.

Both cannabinoids have their benefits. The big takeaway though is that CBD is safe to take even in higher doses. You might waste your money on the substance but the chance of you experiencing any severe side effects are low.

When it comes to THC though, the dosage is everything. To get a benefit out of THC less is more. People think that having more THC in their product is better when, in fact, the opposite is true.

Side Effects

Everyone’s body reacts differently to CBD and THC. There are side effects for CBD which you might experience but they are temporary and don’t leave any lasting damage.

Possible short term side effects of CBD are

  • fatigue
  • decreased appetite
  • irritability
  • stomach problems

Side effects for THC are more severe though and could leave long-lasting damage. Apart from the psychoactive high effect, THC might have a negative effect on male fertility. There is evidence, that men, who smoke marijuana on a regular basis, can have a reduced sperm count and abnormal sperm behaviour.

The second problem of THC is the possible negative impact on learning and social skills. Studies have shown that heavy marijuana use can have a negative impact on

  • learning
  • remembering information
  • functioning in society

Heavy marijuana use is defined as usage in 27 out of 30 days. Even after the heavy usage of THC has been stopped, people’s ability to memorise information was still lower than before the THC use. This can also result in long term memory loss.

Other short term side effects of THC are

  • confusion
  • increased heart rate
  • decreased sleep quality and issues falling asleep
  • increased sweatiness
  • dry mouth
  • red eyes
Male hand pointing to No on THC


The legality of both compounds depends on the country you are in. CBD has been made legal in most countries in the last few years whereas THC is still illegal in the majority of the world. You also have to distinguish between recreational purpose and medicinal purpose. THC is only legal for recreational purposes in

  • Canada
  • Georgia
  • Uruguay
  • South Africa
  • some states in the USA

A few more countries opted to decriminalise THC making possession of it a non-criminal offence. On top of that, some other countries have legalised THC for medicinal use but a special prescription is needed to get your hands on THC through that way.

CBD, on the other hand, has been legalised in many more countries around the globe in recent years. It is still country to country-specific but compared to THC you can enjoy CBD in more locations.

Due to the increased research effort knowledge and evidence of its benefits is on the up. Thus, more countries are expected to legalise CBD in the future.

In the UK CBD is legal provided it only contains a tiny amount of THC. Or one milligram of THC per package to be precise. You can learn more about the legality about CBD and growing hemp in the UK here.

The USA has legalised CBD with the US Farm Bill in December 2018. But, states are still allowed to overrule this on a state level. Hence why you need to be careful in the USA when travelling from state to state with CBD in your bag.

Not all states have opted to follow the federal ruling and in some states, you need a medical prescription to consume CBD.


Below is a summary of the key aspects of both compounds:

IllegalNoIn most countries
LegalIn most countriesNo
Produces a “high”NoYes
Interacts with endocannabinoid systemYesYes
Side effectsAlmost nonePsychoactive side effects
Shows on a drug testMaybe**Yes
Pain relieverYesYes
Reduces nauseaYesYes
Eases migrainesYesYes
Reduces anxietyYesYes
Eases depressionYesNo
Decreases seizuresYesNo
Helps with insomniaYesYes
Helps with psychosisYesNo
Increases appetiteYesYes
Used for various other conditionsNoYes
Characteristics of CBD and THC

*CBD can be derived from the hemp plant as well as the marijuana plant. The difference is that hemp plants will only contain trace amounts of THC. The threshold in the USA is a maximum of 0.3% THC and in the UK 0.2% THC for hemp plants. In contrast, marijuana plants can contain up to 30% THC in dried condition.

**Pure CBD does not show on a drug test. But, CBD products can contain trace amounts of THC which might get you into trouble with law enforcement.

Are you taking CBD, THC or a product containing both compounds? What are your experiences and why are you taking it? Let me know your experiences in the comment section below and sign up to my blog for weekly updates.

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