EducationA comprehensive beginners guide to CBD dosage

A comprehensive beginners guide to CBD dosage

9 min read

Lucy MacKinnon

A comprehensive beginners guide to CBD dosage

CBD, or cannabidiol, is a non-intoxicating but still psychoactive medical cannabis compound that has recently taken the global health and wellness industries by storm. Extracted from cannabis and hemp plants, CBD is often then mixed with carrier oils, excipients, and other cannabis chemicals like terpenes and flavonoids to create CBD oils, edibles, and topicals.


CBD has been used to manage a variety of health concerns and conditions, from anxiety to arthritis, by an estimated 7.3 million adults in the UK. But, with so many product forms and varying ingredient concentrations, working out what dosage to take is a common obstacle at the start of many patients' CBD journeys.

Typically, new consumers are unsure of how much CBD to take per day, however, most products do come with dosage recommendations. Typically, experts suggest increasing the recommended starting dose in 5 ml increments until the desired effect is reached, however, there are a number of factors that affect CBD dosage.

We’ve written this article to explain any questions you may have about how much CBD to take, or what precautions should be taken when you first start taking CBD. Here we establish the dos and don'ts of CBD dosing, and as always, we recommend discussing your individual needs with your doctor or clinician.

Factors that affect CBD dosage

Just like many other types of medications, CBD dosages are tolerated differently depending on the patient or person. Factors like age, gender, and body weight can all influence a person's tolerance to cannabidiol, making their ideal dosages different. The severity of symptoms or conditions being treated with CBD also influences dosage recommendations.

Both CBD dosage charts and clinical prescribers often recommend consuming CBD in a milligram to kilogram of body mass ratio, this is because body weight has been known to impact the absorption and metabolism of drugs. Studies have also suggested that cannabis compounds affect men and women differently due to their difference in hormones. However, there are very few studies that investigate the effects of CBD on women, so it is difficult to make a gender-based comparison without further research.

Extra safety is advised for seniors when calculating CBD doses, and some experts advise starting with an extremely low dose, such as 2.5 mg, or half of the dose recommended by the products’ manufacturer if they are new to CBD. When taken alongside certain prescription medications, CBD can interfere with their absorption and effects within the body, which can cause unpleasant side effects such as vomiting or diarrhoea. Senior patients can be more sensitive to side effects like these, and they also have a higher risk of encountering them. This is due to higher rates of comorbidity in people over the age of 65, so extra precautions are advised when starting CBD treatment.

Not only do human variables affect CBD dosages, but the varying ingredients in different CBD products can also influence their effects and therefore, their doses. CBD-based products can be categorised into three product types. Isolate products, just as their name would suggest, are made with pure cannabidiol, whilst full spectrum products contain CBD along with every other compound found naturally within the cannabis plant, including up to 1 mg of THC per product container. A good middle ground is offered by broad-spectrum CBD products because they don’t contain THC, but they do contain other cannabis terpenes, flavonoids and other cannabinoids just like full-spectrum products.

Difference in dose

Humans have shown the ability to tolerate up to 1500 mg of CBD per day, however, depending on the symptoms being treated, daily doses of CBD oil can range from anywhere between 5 mg and 600 mg depending on the patient and product. The anxiolytic, or anxiety-reducing, properties of CBD were displayed during a public speaking test when subjects were given 300 mg of CBD. Another study focusing on Bowel Disease noted that just 10 mg of CBD per day has the potential to reduce inflammation.

This study found that CBD dosed to a 300 mg/kg ratio may prevent Graft-Versus-Host Disease (GVHD) in transplant patients with acute leukaemia and other rare cancers. In the conclusion of this Phase 2 trial, researchers explained that in combination with standard GVHD treatment, CBD is a ‘safe and promising strategy to reduce the incidence of acute GVHD’.

A small-scale study investigated the effects of different CBD dosages on patients with Parkinson’s Disease. This study found that mild side effects were experienced at each dosing stage between 5 mg/kg and 25 mg/kg, however, the best-tolerated dose for Parkinson’s patients was 15 mg/kg. The study noted an improvement in nighttime sleep scores, emotional and behavioural dyscontrol, and a beneficial effect on total and motor MDS-UPDRS scores.

Although CBD is not believed to be toxic unless around 20,000 mg is taken in one day, it is still advisable to take the necessary precautions outlined in this article to avoid adverse reactions. If too much CBD is taken, or it interacts with other medications in the system, negative side effects can ensue. An increase in fatigue, a loss in appetite, and instances of diarrhoea have all been linked with inaccurate cannabidiol dosages, and so to avoid these it is important to calculate dosages carefully.

How to determine your ideal CBD dosage

Once you have decided which type of CBD product best suits your needs and lifestyle, it is time to work out how much CBD to start with. When calculating dosages it is essential to remember how personal factors such as age, weight, gender, and tolerance can influence effects and so, the ’start low and go slow’ policy is often advised. 

Some CBD products do provide their own dosage charts, and there are also a number of dosage calculators available online for those that don’t. Here consumers can input their personal data to have their ‘optimal dose’ of CBD calculated in milligrams, however, these tools are not always accurate.

For the best possible health results, you really can't go past seeking the advice of a doctor that is registered to prescribe medicinal cannabis, and one that has experience doing so for your particular health concern. Not only do these doctors have the tools to accurately calculate ideal CBD dosages, but they are also able to provide an in-depth assessment of the potential side effects and interaction risks associated with taking cannabidiol. 

Most CBD products are either broad-spectrum or full-spectrum products and so, they contain many other ingredients such as other cannabinoids, flavonoids, and terpenes from the cannabis plant. Additional excipients are also sometimes added to influence the texture, taste, or aroma of CBD products. In the presence of other ingredients like carrier oils and thickening agents, 1 ml of CBD oil does not equate to 1 ml of CBD, so it is important to calculate the CBD contents, as opposed to the quantity of liquid.

As a general rule of thumb: 10 ml tincture bottles typically contain 200 drops, and so, if 10 ml of CBD oil contains 1500 mg it is safe to presume one drop contains 7.5 mg of cannabidiol. Similar maths can be applied to edible CBD products or drinks that contain CBD.

CBD dosage tips

Learn the ABCs of CBD

First, we’d recommend doing your research. Find out what kind of CBD product feels most comfortable to you, that could be easily incorporated into your daily routine, and best benefit your lifestyle. Check out the rest of our CBD series for the ultimate guide to help you through the start of your CBD journey.

Start low and go slow

Secondly, it’s a good idea to start with a low dosage to see how your body reacts to cannabidiol. If needed, this dose can then be built up slowly and gradually until you find the desired effects and correct dosage. By increasing in very small increments, the risks of experiencing negative side effects to CBD are decreased.

Drop in with the doctor

Finally, it is always important to consult with your doctor, and not only if any adverse reactions are experienced. CBD has been known to interact with certain types of prescription medications, which can have varying levels of severity. Certain medications should be completely avoided when using CBD as they can be ineffective or have increased side effects in the presence of cannabidiol, whilst other commonly prescribed medications have shown to be unproblematic when taken with CBD. This is why it is essential to get individual advice from your doctor.


When determining your ideal CBD dosage, we’d recommend following a simple set of rules, to maximise the plant's potential, whilst minimising the risk of side effects.

By seeking the advice of a doctor that has experience prescribing cannabis-based medications, you will be able to accurately calculate an ideal CBD dosage for your individual needs and lifestyle.

We also recommend taking the time to do your own research into what kind of CBD product best suits you, as well as starting with a low dose and gradually building up until desired effects are achieved. This will help you to experience the full potential of CBD, with minimal risk.

Releaf understands the importance of medical cannabis in treating various medical conditions. With our tailored monthly packages, specialist consultations for medical cannabis, and a unique medical cannabis card for protection, you can access the treatment you need without worrying about the stigma.

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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With five years of journalism and healthcare content creation under her belt, Lucy strives to improve medical cannabis awareness and access in the UK by producing high quality, credible content.

Our articles are written by experts and reviewed by medical professionals or compliance specialists. Adhering to stringent sourcing guidelines, we reference peer-reviewed studies and scholarly research. View our editorial policy.

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