The potential benefits and side effects of CBD for IBS

The potential benefits and side effects of CBD for IBS


With 5 years of cannabis journalism behind her after graduating from De Montfort University and writing for cannabis publications such as The Cannavist, Lucy is a dedicated journalist passionate about cannabis education and culture.

There is a significant body of research that suggests symptoms of irritable bowel syndrome (IBS) may be treated with medical cannabis, and more specifically, cannabidiol (CBD). Now, along with the increasing availability of CBD products through the NHS and private clinics (like us here at Releaf) to treat certain conditions like IBS, it is worth understanding the benefits of CBD treatment, as well as its potential side effects and correct dosage amounts.

CBD is the second most common active ingredient in medicinal cannabis and hemp plants, and an essential component of medical cannabis. It does not produce a ‘high’ as might be associated with recreational cannabis usage, and it can be extracted directly from the plant.

There have been multiple scientific studies on the potential health benefits of medicinal cannabis and its cannabinoids such as CBD on irritable bowel symptoms, in which participants reported a significantly higher quality of life thanks to the treatment. This is primarily due to the anti-inflammatory properties of cannabinoids like CBD, which interact with the body’s endocannabinoid system to help reduce inflammation.

While such studies on the benefits of CBD provide hope for some sufferers of IBS, it’s important to note that its effectiveness is dictated by its dose. The right dose needs to be strong enough to be effective, while weak enough to avoid non-serious side effects such as dizziness or drowsiness.

There are also multiple factors that will determine what dosage is correct for each individual, including body weight, tolerance, and metabolism rate.

CBD dosage for IBS

Before we go any further with this article, we must point out that before beginning any new form of treatment, it is strongly advised that you seek the advice of a specialist doctor that is registered to provide medicinal cannabis. Only they will be able to provide the most up-to-date advice on dosage.

CBD is available in a variety of different consumable forms including oils or tinctures, tablets, natural dried flower, and edible gummies. The CBD dosage of each product is determined by the milligram (mg) amount of CBD in the product, and it is important to identify the correct dosage when using CBD to treat IBS symptoms.

The effects of CBD on each individual will be influenced by these factors:

  • body weight
  • tolerance
  • metabolism

Let’s look at how each of these factors influences the effectiveness of a CBD dose.

Body weight

Many pharmaceutical drugs can be prescribed in a ‘one-size-fits-all’ manner, but many cannot, as their effectiveness is impacted by an increased body capacity. It can also be dangerous, as a dose that is safe and suitable for a 90 kg man may significantly increase the risks of side effects for a 55 kg woman.

More research is needed on the impact of body weight on CBD dosage, but it is better to be safe and take into consideration the size and weight of your body when calculating your first dose.


Some people love a strong cup of coffee in the morning to liven them up for the day ahead, while others find it makes them feel too hyper and fidgety and thus avoid it altogether. It is the same with pretty much any substance, as people have different natural tolerances to different things, so this is another factor that should be considered when calculating your first dose of CBD.

It can also change over time, with our natural tolerance increasing as our bodies become accustomed to a substance’s presence in our bodies.

As we will discuss in more detail further below, it’s better to start with the assumption that you have a low tolerance for CBD, and thus begin with a low dose before slowly building it up to its optimal effectiveness.


There are also a number of genetic factors that influence how each of our metabolisms process different substances. The metabolism is the group of life-sustaining chemical reactions in our bodies which convert the likes of food and medicine that we consume into energy that powers our cellular processes.

As different people have different metabolism rates, it can influence the correct dose of CBD. In the case of two people of the same size, weight and natural tolerance, it’s better for the one with the slower metabolism to take a lower dose.

Of course, it can be difficult to determine exactly what kind of metabolism we have without some medical insight, so again it is better to start with a lower dose and work up from there to find the sweet spot.

Let’s look closer at starting doses as well as maintenance doses.

CBD starting dosage and maintenance dosage

The recommended starting dosage of a CBD treatment for IBS is unlikely to be the most effective dose, as everyone should be starting very low in order to avoid any potential side effects. While they are not considered serious side effects, they can still be unpleasant and are best avoided.

Potential side effects from too high a dose include:

  • dizziness
  • drowsiness
  • nausea
  • decreased appetite
  • diarrhoea

So, always start low to account for factors such as the body weight’s impact on the dosage, as well as your natural tolerance level and metabolism rate. From the low starting dose, you can work your way up in increments to find your maintenance dose.

The maintenance dosage will be the dose that is effective for your symptoms but does not produce any of the side effects.

It’s also important to consult with a healthcare professional before starting any CBD treatment for IBS, especially if you are taking any other medicines at the same time. There is the possibility that CBD interacts with the other medical products you are taking, so always speak to a medical expert to ascertain the potential for any issues.

Finding the right CBD dosage for IBS

The first step in finding the right dosage of CBD for IBS is determining what method of ingesting CBD is your preference.

Some people prefer to inhale CBD via a vaping device. The CBD and any other cannabinoids in such products are absorbed through the lungs after inhaling the vaped product.

For oral ingestion, tablets and edible gummies can be eaten and swallowed, with the CBD being absorbed through the intestines.

CBD oils and tinctures can be used for sublingual administration, which involves spraying or placing drops of the product underneath the tongue. The capillaries under the tongue quickly absorb the oil, causing the CBD to enter the bloodstream quickly.

Topical application involves rubbing a cream containing CBD onto the skin, which then absorbs the CBD through the pores.


Ultimately, there is no standard dose of CBD that suits everybody, and each individual will need to consider their body weight, tolerance, and metabolism when calculating a dose. However, regardless of these factors, it’s always advisable to seek the advice of a medical professional and to start with a low dose and work up in increments until the treatment becomes effective. The effective dose then becomes your maintenance dose, which should not be exceeded in order to minimise the chance of experiencing any side effects.

Interested in finding out more? 

Well, you're in the right spot then!

Here at Releaf, we believe that access to medical cannabis is important. That's why we offer tailored monthly packages based on your cannabis prescription, specialist consultations for medical cannabis, and a unique medical cannabis card for protection. 

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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