CBD is a non-intoxicating cannabinoid with an excellent safety record. However, as with many supplements, consuming too much can produce adverse effects.
In most cases, taking too much CBD will produce only mild side effects, but at very high levels, it can become toxic and could produce an overdose.
According to the World Health Organization, "CBD is generally well tolerated with a good safety profile". However, it can produce some side effects and interacts with some medications.
The risk of these side effects is likely to increase if you use a larger serving. Studies indicate that too much CBD may, for some people, result in drowsiness, stomach discomfort, nausea, and diarrhoea.
It’s also important to be aware that CBD is a biphasic substance, which means it produces two distinctive results when taken in different amounts. Small servings of CBD are more suited to daytime use and larger quantities are best for use in the evening. Consequently, the amount you take will affect the results you experience. If you're hoping for a mild result but take too much, you may experience effects that you were not expecting.
In 2019, a child was admitted to the hospital after being found unresponsive. Doctors discovered that he had eaten CBD. The initial tests indicated that he had consumed a large amount of THC. He fully recovered in 72 hours. When they tested the product he had taken, the results showed only tiny traces of THC.
In 2020 a 56-year-old man was hospitalised after taking a total of 370mg of CBD from two packets of gummies. He experienced slurred speech and vomiting and had completely recovered by the next day.
While both these incidents are not entirely explained, they indicate that while taking too much CBD or overdosing on CBD is unlikely, it's not impossible. They also raise the point that it's essential to only get CBD from trustworthy retailers (the 56-year-old man purchased his from a petrol station) that display their CBD and THC content clearly and have it backed up by third-party lab results.
Drugwise describes an overdose as taking more of a drug than medically recommended or more than the body can tolerate.
The symptoms of an overdose vary depending on the substance that caused the overdose. However, some can result in death; "Deaths from an overdose may be from heart failure (where the heart rate is slowed or stopped), liver failure (where the body is unable to eliminate the drug fast enough leading to poisoning) or respiratory failure."
CBD overdose is extremely unlikely and there are no recorded cases of anyone dying from taking too much CBD. Studies conducted with monkeys found that daily amounts of up to 300mg per kg of body weight increased the size of the animals' liver and kidneys but had few other effects. One piece of research stated that 20,000mg of CBD is considered to be toxic, but it hasn't been tested or observed in humans.
A recent investigation reported that CBD might damage the liver if taken in extremely high amounts. 50mg per kg of body weight, the equivalent of 4,000mg for an 80kg adult, may produce liver swelling and damage. At 200mg per kg of body weight, 16,000mg for an 80kg adult, the liver will likely develop signs of toxicity.
Some CBD products contain trace THC. UK controlled-drug rules do not set a simple 1mg-per-container THC limit for every CBD product; the 1mg figure is one part of a specific exemption for some products or preparations. Product lab data can show the cannabinoids detected, but a legal threshold should not be used as a guide to safe intake.
In 2014, research into the toxicity of THC reported that 30mg of THC per kg of body weight is toxic and results in a 50% chance of death. An adult weighing 80kg would need to take 2.4g of THC to reach this level.
If you experience side effects or symptoms after taking CBD such as drowsiness, stomach discomfort, nausea, and diarrhoea, don't take any more and contact your doctor immediately.
If you suspect that you or someone else is experiencing a CBD overdose, you must call 999 immediately. You should also call 999 if you or they experience:
If you think you may have taken too much CBD and you need urgent medical help, you can either contact your doctor or use the NHS 111 service.
The Food Standards Agency advises healthy adults to limit their total CBD intake from food to 10 mg a day as a precaution.
How CBD affects you depends on various factors, including body mass, body chemistry and general health. An amount that may suit one person may feel like too much for someone else. A common approach has been to start with a small amount and increase gradually.
If in doubt, consult with a healthcare practitioner before using CBD.
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Tom Russell
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Tom Russell writes extensively about CBD oil and other groundbreaking food supplements. He and his wife share their home with two daughters and a lifetime’s collection of books.