To date, the FDA have only approved one cannabis-derived product, which is called Epidiolex, and it is only available by prescription. This approval covers the treatment of seizures in people with severe types of epilepsy called Lennox-Gastaut syndrome and Dravet syndrome.

The dosage for Epidiolex, a form of CBD oil, is as follows:

• The starting dosage is 2.5 milligrams per kilogram of body weight (mg/kg) twice daily, making a total dosage of 5 mg/kg each day.
• After 1 week, people may increase the dosage to 5 mg/kg twice daily, which is a total of 10 mg/kg per day.

All other products that contain CBD fall outside FDA regulations, so there are no official guidelines for their dosage. Some manufacturers are advertising CBD products with unproven medical claims, and the quality and safety of these products can vary.

Before using any other CBD products, a person should speak to their doctor about appropriate dosages.

The dosage that a person takes will depend on the method of administration that they are using and the specific product. Methods of administration include:

• CBD oil solutions
• CBD capsules
• tablets that a person places under the tongue (sublingual)
• nasal sprays

Recently, a wider range of products containing CBD has become available. These items include food products, dietary supplements, cosmetics, and animal health products.

Research into CBD therapy is still in its early days, and scientists need to conduct many more research studies to determine the benefits and risks of CBD products. Importantly, researchers need to work out the ideal CBD dosages that are both safe and effective for each condition.

As a therapy, CBD oil has gained a high level of research interest. At Medical News Today, we have covered what the research to date has shown about the role of CBD in the following conditions:

According to a World Health Organization (WHO) report, research has suggested that CBD oil may also have therapeutic benefits for the following conditions:

As the FDA have only approved the use of CBD for specific forms of epilepsy, doctors know little about what dosage people should take when they use it for other reasons. As with any drug, the appropriate dosage is one that provides a therapeutic effect and is well-tolerated.

In clinical studies, researchers have used various oral dosages of CBD, ranging from 100–800 mg per day.

Some studies use even higher dosages. According to a review, an individual reported an improvement in psychosis after taking 1,200 mg per day for a few weeks. In another study, people with schizophrenia reported benefits after taking increasing dosages of 40–1,280 mg per day for 4 weeks.

In a study into the effects of CBD in people with Parkinson’s disease and psychosis, six participants showed significant improvement in symptoms with a dosage of 150 mg per day of CBD.

The following table lists the method of administration and dosage of CBD that researchers have used to study its therapeutic effects on different medical conditions.

To find out whether a CBD product is safe and to determine the effective dosage, people should consult a doctor.

Several factors may influence the dosage that people can take. Depending on the medical condition or the reason why a person is taking CBD, they will need a different dosage.

Some people need high dosages to control epilepsy, whereas smaller dosages may be effective for anxiety.

Another factor that people should consider before using CBD is their weight. In many clinical trials and when using Epidiolex, doctors calculate a dose per kg of body weight. People who weigh less should, therefore, take lower dosages than people who weigh more.

Alcohol and other central nervous system depressants may increase the sedation effect of CBD. People who use other medications that can cause drowsiness should avoid or lower their dosage of CBD. Before mixing alcohol and other medications with CBD, a person should ask their doctor whether it is safe.

People must also consider the dosage in each form of CBD. A capsule of CBD has a specific dosage, but the dosage of oral solutions depends on the volume. For example, a CBD solution containing 25 mg per milliliter (ml) can provide 125 mg if a person takes a full teaspoon, which equates to 5 ml.

Although data in humans remain limited regarding the effects of taking pure CBD, researchers suggest that it has relatively low toxicity.

In monkeys, CBD does not affect bodily functions or behavior unless the animals receive dosages higher than 30 mg/kg orally each day for 90 days or 150 mg/kg intravenously.

In a human physical dependence study, researchers gave people 1,500 mg per day of CBD for 4 weeks. The study participants did not go through withdrawal after the 28 day trial. Another study found that doses up to 1,500 mg per day were well-tolerated.

The World Health Organization (WHO) also report that people usually tolerate CBD well. CBD does not cause a “high,” and it does not have the same potential for abuse as cannabis.

The data on the safety of CBD are limited. The data that are available point to possible risks that people must consider before taking CBD for any reason.

Some side effects of CBD are noticeable, including:

• drowsiness or other changes in alertness
• digestive issues, such as diarrhea and decreased appetite
• changes in mood, such as irritability and agitation

Other side effects can happen without people being aware of the cause, such as:

• liver failure
• interactions with other medications
• injuries that result from mixing alcohol or other depressants and CBD

Several factors determine what CBD dosage a person can take, including the intended use and the person’s weight. Although evidence is still lacking, researchers have identified some drugs that interact with CBD, which may also affect the dosage that a person can tolerate.

The FDA have only approved one CBD product. Research on the possible uses, dosages, benefits, and safety of CBD is ongoing.