CBD side effects

The possible side effects of CBD

We like to talk a lot about the fantastic effects of CBD and the amazing health benefits it offers.

But lots of people want to know... Does CBD have any unwanted side effects?

Research tells us that there are many benefits of the hemp plant - including CBD. However, at this point, we know there have not been enough clinical trials and the side effects of CBD haven’t been fully researched scientifically.

The existing scientific studies we do have, have not indicated many significant side effects. What's more, the World Health Organisation (WHO) have stated that CBD is considered safe to use.

In fact, side effects occur only occasionally in studies, and then only in mild form. We've taken a look at some of the current research available.

CBD side effects

CBD side effects... in a nutshell

  • The use of CBD in the UK is increasing dramatically. CBD is used for medical conditions such as chronic pain, insomnia, epilepsy, Parkinson's disease, anxiety and depression - as well as many others. It is proven to have anti-inflammatory and pain relieving properties. The overall opinion is that the benefits of CBD far outweight any mild side effects.
  • One of the benefits of using CBD is that the side effects, if indeed there are any, are far more mild than some conventional medication. For example, antidepressants and antipsychotics.
  • According to scientific studies, the vast majority of consumers have no issues with cannabidiol (CBD).
  • In particular, no significant side effects on the central nervous system, vital functions or mood have been found.
  • This is also supported by a 2018 investigation report by the WHO which classifies the CBD as safe.

What side effects have been observed?

Studies have found that the benefits far outweigh the potential side effects of CBD.

And in comparison with conventional medication, there is significantly less risk of side effects.

The following side effects were occasionally reported in the studies we examined:

  • Fatigue - CBD is considered a natural sleep aid, it is also used as a sedative and may cause drowsiness. You should therefore be careful when driving a car or operating machinery.
  • Diarrhoea - indigestion has been reported sporadically after consuming high amounts of CBD.
  • Change in appetite.
  • Slight dizziness or light-headedness - CBD can cause a temporary small drop in blood pressure. A cup of tea or coffee can help here.
  • Dry mouth - like other cannabinoids, saliva production may be temporarily reduced. The mouth can feel dry and cause thirst.
  • Increased tremor in Parkinson's patients - Early studies have shown that CBD can worsen tremor and muscle movement in people with Parkinson's diseas
  • Inhibition of P540 enzymes - particularly important for interactions with other drugs. In this context, the so-called grapefruit test must be observed (see below)
  • People with glaucoma should avoid CBD as it can increase intraocular pressure
A medical consultation is advisable, especially during pregnancy, because CBD influences specific proteins. This can cause undesirable changes in placenta function.
Studies have found that the benefits far outweigh the potential side effects of CBD

Study Example

In 2017, a clinical trial was conducted on patients with epilepsy. More specifically, Dravet Syndrome. There were 120 patients in total, including both children and young adults who were already taking medication for epilepsy.
The subjects were split into two groups. One who took 20mg (per kg of body weight) of CBD a day, and one who took a placebo. A definite difference between the two groups were found. The frequency of seizures decreased from 12.4 to 5.9 in the treatment group and 14.9 to 14.1 in the placebo group. The percentage of patients who became seizure-free was 5% with CBD and 0% with the placebo.
It was noted however, that side effects did occur in 75% of the patients. The study does not go into great detail of the gravity of the side effects but they did include diarrhea, vomiting, fatigue, increase in temperature and drowsiness. The latter being the most common. It is suggested by some that the side effects could have been due to the interaction between CBD and the epilepsy medication.

Interestingly, the only FDA (Food and Drug Administration) approved CBD drug legally available on prescription is one used in the treatment of epileptic seizures. Epidiolex, sometimes known as Epidyolex, is used to treat Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex.

We find this interesting because it shows that CBD can be, and has been, accepted in the conventional world of medicine. Why not for other conditions?

Whilst we know there has been a lack of clinical trials, CBD has shown great potential in other significant medical conditions, such as schizophrenia and psychosis.

We genuinely hope to see CBD more widely accepted and look forward to watching this progess unfold in the coming years.

Interactions with other medicines may occur when ingested

Interactions with other medicines can lead to undesirable effects when taking different prescriptions.

These drug interactions can sometimes mean the pharmacological effect is strengthened.

But it is also possible that the effect is weakened or even - in the worst case scenario - cancelled.

Experts believe that the oil can interact with some medications when ingested.

Before consuming CBD, you should discuss with your doctor if you want to take CBD with medication. In this context, scientists in the United States regularly mention the so-called grapefruit test .

This is because individual active ingredients in grapefruit interact with medications similar to CBD.

Chemical compounds exist in both that inhibit the expression of some cytochrome P450 enzymes. This family of enzymes metabolizes most of the drugs used to treat humans.

For this reason, doctors regularly warn against consuming grapefruit while taking certain medications.

If your doctor advises you to avoid grapefruit during treatment, you should refrain from taking CBD. WebMD offers a list of medications that are affected by grapefruit in their article on drug interactions.

Collected experience on side effects of CBD

Our team has evaluated hundreds of experiences from consumers about side effects of CBD. If you do not suffer from epilepsy, glaucoma or Parkinson's, side effects have hardly occurred.

The most common side effects from the experience gained are fatigue, upset stomach and increased appetite.

However, these are all very mild and some consumers even point out that it is important to eat enough food whilst taking CBD products.


Can CBD lead to nausea or diarrhoea?

Yes, there have been isolated incidences of subjects reporting nausea and diarrhoea in scientific studies. But these effects were reported as exceptions. The vast majority of all subjects had no problems with CBD in previous studies.

Interestingly, there are opinions that CBD could also be used to combat nausea and diarrhoea!

CBD and nausea

There is little scientific evidence that we have found in relation to nausea as a side effect. We list nausea as a side effect based on reports we have heard or read, rather than coming from scientific studies.

In actual fact, the main scieintic evidence we have on CBD and nausea suggests that CBD actually works specifically to reduce nausea. The non-intoxicating cannabinoid CBD interacts with serotonin receptors and can thus counteract the feeling of nausea.

Therefore, CBD is often used for cancer patients who suffer from severe nausea as a result of chemotherapy.

If you have expeirenced nausea, or if you are concerned about potentially experiencing nausea, try small amounts of low concentration CBD to see how your body reacts. More is not always better in the world of CBD. It may also be that you are using a bad brand of CBD. Choosing a high quality product is really important.

CBD and diarrhoea or constipation

Similar to above regarding nausea, diarrhoea and constipation can also be treated with CBD, but they can also occur as a side effect of this plant.

Some people have reported mild indigestion, including diarrhoea, from taking high doses of CBD. In this case, it is advisable to try lower doses, or to stop consuming it.

It is generally advised to start with a low dose of CBD, and work your way up until you find the right dosage for you.

Can CBD cause headaches as a side effect?

The most commonly reported side effects are dizziness, tiredness, headache and a dry mouth. It is interesting that some people report headaches with CBD use because one of the most common uses of CBD is to treat migraine headaches.

The Skaggs School of Pharmacy and Pharmaceutical Sciences - University of Colorado, conducted a study in 2016 to test the use of medical cannabis to treat migraine headaches.

The results were very promising. Research statistics concluded that CBD has helped reduce the incidence of headaches by more than 50%, from 10.4 to 4.6 headaches per month.

Despite these conclusions, doctors are debating whether CBD oil can also cause headaches.

A drug that minimises a particular condition can trigger the same condition in different situations. In a way, it can be compared to many modern drugs, for example, acetaminophen is good for headaches, but it can also cause them.

According to Cannabis and Cannabinoid Research (2017), CBD can cause diarrhoea, fatigue, and problems related to weight and appetite. This study also never mentioned headaches as a possible side effect of CBD oil.

Does CBD give you the munchies?

A well known side effect of the cannabis plant is that it increases your hunger and appetite levels. And it isn't for salad either. The culprit of this over-active appetite is tetrahydrocannabinol, more commonly known as THC. This is the main psychoactive cannabinoid, i.e. the one that makes you high; CBD doesn’t. The two cannabinoids affect appetite in different ways. CBD, by contrast, does not give you the 'munchies'

The Washington Post offers an excellent article about why THC increases appetite.

CBD should then, according to experts, be able to give you many of the benefits of cannabis without leaving you with a hunger that's never sated and an empty fridge. Some products can contain traces of THC, but this amount shouldn't affect appetite.

Despite this, there have been reports of people feeling hungry after taking CBD. One answer may be that the more cannabinoids and terpenes are present in the product, the more it can affect ones appetite due to the entourage effect. If you’re already feeling hungry before and your blood sugar is low, the CBD may slightly enhance those hunger feelings. It's worth remembering then, that, a full-spectrum product may result in a small increase in appetite, as opposed to using CBD isolates.

Experts have stated that it may be possible to use CBD in the treatment disorders of eating disorders: not only in the suppression of appetite to counter our susceptibility to the over-consumption of highly pleasurable and energydense foods; but also in the treatment of conditions that involve reduced appetite and weight loss.

Are there any side effects of CBD on dogs?

As with everything you give your dog, it is advisable to check whether CBD is safe for your four-legged friend. While there is some debate in the veterinary community about the effectiveness of CBD, CBD oil is generally considered to be very low risk for dogs.

There have been animal studies with CBD. And it has been found that in some dogs, mild side effects can occur. The most common being - like people - increased sleepiness. As always, proper dosage is important.

If your dog eats too much, it can lead to dry mouth, diarrhoea or dizziness. These side effects for CBD in dogs are comparable to those in humans.

Still unsure whether you want to give your pet CBD? No problem! We've covered everything you need to know to make the right decision for you and your furry friend.

While CBD oil is considered relatively safe, you should contact a veterinarian if you have any questions because not all CBD oils are made the same way or contain the same ingredients.

We advise you to check how the product is made and to make sure that it does not contain any harmful additives. Under no circumstances should you give your dog products that contain THC, because THC is very harmful for dogs.

Our conclusion

From the limited research available to us, we know the effects of CBD can be beneficial to both general wellness and significant medical conditions.

We know that CBD has been accepted by conventional healthcare in the treatment of epilepsy. Although we remain confused as to why it has been accepted here and not for other conditions.

We know that side effects can occur, but that these have generally been mild and insignificant. It is generally acknowledged that the benefits of CBD far outweigh the side effects.

However, you need to aware that this is a possibility. Different people react differently to CBD. Therefore it is recommended that you start with a low dose and see how your body reacts. If you do experience any adverse side effects, either lower your dose, or if the side effects are signifcant, cease taking CBD altogether.

There are so many CBD products available. CBD oil in tinctures, CBD gummies, topical creams, tea bags, pure CBD - like crystals are available, as well as vaping. If you do experience some side effects, you can always try another product.

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