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How much CBD should you take?

There is no standard CBD dose, and this site does not recommend one. In Australia the prescriber sets the dose. Here are the doses trials used.

Facts checked 13 November 20263 min readHow we research

There is no single correct dose of CBD, and this site does not recommend one. In Australia the dose is set by the doctor or nurse practitioner who prescribes it, for one person and one condition, taking into account your other medicines and your liver health.1 What we can show is the doses that clinical trials used and what happened.

What doses have trials used?

Condition Dose Result
Dravet syndrome (a rare childhood epilepsy) 20 mg/kg a day, added to other medicines Seizures fell more than with placebo2
Social anxiety, public-speaking test Single 600 mg dose Less anxiety during the speech than placebo3
Insomnia 150 mg nightly Similar to placebo on most sleep measures4
Acute low back pain Single 400 mg dose No better than placebo5
Hand osteoarthritis 20 to 30 mg a day No difference from placebo6
Knee osteoarthritis 600 mg a day No difference from placebo. More liver enzyme rises on CBD7

“Placebo” means a dummy treatment. The full table, with more conditions, is in the CBD dosage guide.

Two patterns stand out. The strongest evidence is at very high doses: for a 70 kg adult, the epilepsy doses work out at roughly 700 to 1,750 mg a day. And a bigger dose did not rescue a failed use: pain trials found no benefit at 20 to 30 mg, 400 mg or 600 mg.567

What about small doses?

An Australian review of oral CBD at 400 mg a day or less found that benefits “became more clearly evident at doses ≥300 mg”.8 The same researchers wrote that very low doses, about 5 to 25 mg, have little evidence of health benefit.9 See does low-dose CBD work?

Do higher doses carry more risk?

Yes, for the liver in particular. In a US Food and Drug Administration study, 5.6% of healthy adults taking about 350 to 400 mg a day for 28 days had liver enzymes above three times the normal limit, against none on placebo.10 Food also matters: a high-fat meal raised total CBD exposure about 4-fold.11 See CBD and the liver.

How is a prescribed dose usually started?

Prescription CBD is usually started low and stepped up, which is called titration. The TGA says treatment should be stopped if benefit has not been demonstrated.12 If you have a prescribed dose and need to turn milligrams into millilitres, the dose calculator does the arithmetic.

Read the full guide: CBD dosage: what trials used and how prescribers decide.

Footnotes

  1. NPS MedicineWise. Medicinal cannabis: what you need to know. https://www.nps.org.au/professionals/medicinal-cannabis-what-you-need-to-know ↩

  2. Devinsky O, et al. Trial of cannabidiol for drug-resistant seizures in the Dravet syndrome. New England Journal of Medicine, 2017. https://doi.org/10.1056/NEJMoa1611618 ↩

  3. Bergamaschi MM, et al. Cannabidiol reduces the anxiety induced by simulated public speaking in treatment-naive social phobia patients, 2011. https://pubmed.ncbi.nlm.nih.gov/21307846/ ↩

  4. Narayan AJ, et al. Cannabidiol for moderate-severe insomnia: a randomized controlled pilot trial of 150 mg of nightly dosing. Journal of Clinical Sleep Medicine, 2024. https://pubmed.ncbi.nlm.nih.gov/38174873/ ↩

  5. Bebee B, et al. The CANBACK trial of oral cannabidiol for acute low back pain in the emergency department. Medical Journal of Australia, 2021. https://www.mja.com.au/journal/2021/cannabidiol-no-better-placebo-low-back-pain ↩ ↩2

  6. Vela J, et al. Cannabidiol treatment in hand osteoarthritis and psoriatic arthritis: a randomized, double-blind, placebo-controlled trial (conference abstract; full paper in Pain, 2022). https://acrabstracts.org/abstract/cannabidiol-treatment-in-hand-osteoarthritis-and-psoriatic-arthritis-a-randomized-double-blind-placebo-controlled-trial/ ↩ ↩2

  7. Pramhas S, et al. Oral cannabidiol as add-on to paracetamol for painful chronic osteoarthritis of the knee. Lancet Regional Health Europe, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC10682664/ ↩ ↩2

  8. Arnold JC, McCartney D, Suraev A, McGregor IS. The safety and efficacy of low oral doses of cannabidiol: an evaluation of the evidence. Clinical and Translational Science, 2023. https://pubmed.ncbi.nlm.nih.gov/36259271/ ↩

  9. Arnold JC, et al. Prescribing medicinal cannabis. Australian Prescriber, 2020. https://www.nps.org.au/assets/p152-Arnold-et-al.pdf ↩

  10. EurekAlert news release on Florian J, et al., JAMA Internal Medicine, 2025 (cannabidiol and liver enzyme elevations in healthy adults). https://www.eurekalert.org/news-releases/1089832 ↩

  11. US National Library of Medicine, DailyMed. Epidiolex (cannabidiol) oral solution: prescribing information, revised 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩

  12. Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia: overview. https://www.tga.gov.au/resources/resource/guidance/guidance-use-medicinal-cannabis-australia-overview ↩

This page is general information, not medical or legal advice. Laws and evidence change; we show the date we last checked the facts at the top of every page. Talk to your doctor or pharmacist before starting, stopping or changing any medicine.

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