Cannabidiol (CBD) is available in many forms, including oils, tablets, and creams. The ideal dosages vary depending on both the form and usage.

CBD is an active ingredient in the cannabis plant. Products containing CBD may provide some health benefits, but they can also pose risks.

The legal status of CBD products varies among states. The Food and Drug Administration (FDA) does not control most CBD products. The quality, amount of CBD per dose, and safety of the products can vary dramatically, and it is difficult to calculate an optimal dosage.

More research is necessary for doctors to confirm the safe, most effective dosages for each use of CBD.

This article looks at CBD dosages, including current research, factors influencing dosage, and the possible risks of using CBD products.

Is CBD legal?The 2018 Farm Bill removed hemp from the legal definition of marijuana in the Controlled Substances Act. This made some hemp-derived CBD products with less than 0.3% THC federally legal. However, CBD products containing more than 0.3% THC still fall under the legal definition of marijuana, making them federally illegal but legal under some state laws. Be sure to check state laws, especially when traveling. Also, keep in mind that the FDA has not approved nonprescription CBD products, and some products may be inaccurately labeled.

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To date, the FDA has only approved one cannabis-derived product, called Epidiolex, an oral solution 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 to treat seizures 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 daily.
  • After 1 week, people may increase the dosage to 5 mg/kg twice daily, to a total of 10 mg/kg daily.

Doctors may increase this dosage to a maximum of 10 mg/kg twice a day if the affected person tolerates the initial dosage but still experiences seizures.

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

Before using CBD products, a person should speak with a qualified healthcare professional about appropriate dosages.

Administration method

The ideal CBD dosage depends on the method of administration and the specific product. Methods of administration include:

Research into CBD therapy is still in its early days, and more research is necessary to determine the benefits and risks of CBD products, including the ideal dosages for various health conditions.

According to a 2020 review, evidence supports CBD as part of a treatment for epilepsy. However, the authors highlight mixed results on CBD’s benefits for other health conditions, including anxiety, pain and inflammation, schizophrenia, and more.

The authors emphasize the need for more research, particularly focusing on the potential adverse effects of CBD and the lack of regulation in retail products containing CBD.

The following links cover current research on the role of CBD in various conditions:

CBD resources

Visit our dedicated hub for more research-backed information and in-depth resources on CBD.

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As the FDA has only approved the use of CBD for specific forms of epilepsy, doctors may not know what dosage people should take when they use it for other reasons.

According to the 2020 review, dosages in clinical research vary considerably depending on the administration method and the health condition. Daily dosages ranged from less than 100 mg up to 900 mg.

The following table lists some administration methods and dosages from studies in the above review that examine CBD’s therapeutic effects on different medical conditions.

Medical conditionDose of CBDForm
anxiety150–900 mgoral
pain and inflammation250–500 mgtransdermal gel
schizophrenia200–800 mgoral
Parkinson’s disease300 mg dailyoral
Huntington’s disease10 mg/kg dailyoral
post-traumatic stress disorder (PTSD)1.5 mgCBD spray
difficulty sleeping300 mgoral dissolved in corn oil
type 2 diabetes100 mg twice dailyoral
intraocular pressure20–40 mgsublingual

The effectiveness of the above dosages varied in the studies’ results. To find out whether a CBD product is safe and to determine the effective dosage, people should consult a doctor.

The following factors may influence the dosage that people can take.

  • Usage: The medical condition can influence the necessary dosage. For example, some people need high dosages to control epilepsy, whereas smaller dosages may be effective for other health conditions, such as anxiety.
  • 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: Alcohol and other central nervous system depressants may increase the sedation effect of CBD.
  • Other medications: Certain medications may reduce the effectiveness of CBD, which can impact the necessary dose. Similarly, combining CBD with certain medications, such as valproate, may increase the risk of liver toxicity.
  • Form: Dosage may vary depending on the form of CBD. A capsule of CBD has a specific dosage, but the dosage of oral solutions depends on the volume.

People should speak with a qualified healthcare professional before taking CBD to ensure they take the correct dosage.

A 2018 critical review report by the World Health Organization (WHO) states that CBD research suggests a low toxicity level in CBD. However, the report emphasizes that research has not yet explored all potential effects.

CBD does not cause a “high.” However, it may have addictive properties. It may also contribute to respiratory depression in some people, which can require respiratory support.

CBD toxicity does not have an antidote, so avoiding it is vital.

The Centers for Disease Control and Prevention (CDC) also highlights that some CBD products may contain other ingredients that could cause harm, including:

Further research on the safety of CBD is necessary. However, there is some information about potential health risks.

The FDA lists the following potential side effects of CBD:

  • drowsiness or other changes in alertness
  • digestive issues, such as diarrhea and lower appetite
  • changes in mood, such as irritability and agitation
  • liver failure or injury
  • 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 usage, the administration method, and the person’s weight.

Although more evidence is necessary, researchers highlight that some medications and substances can interact with CBD, which may also affect the dosage that a person can tolerate.

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