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Does low-dose CBD work?

Australia caps pharmacist-only CBD at 150 mg a day. That limit was set for safety, not because it works. Here is what trials at or below 150 mg found.

Facts checked 13 November 20268 min readHow we research

Probably not for most of the things people hope it will do, on the evidence so far. Australia’s 150 mg a day limit for pharmacist-only CBD was set because that dose looked safe, not because it was shown to work. Trials at or below 150 mg a day have mostly found CBD no better than placebo (a dummy treatment).

What counts as “low-dose” CBD in Australia?

In Australian law, “low-dose” has a specific meaning. The Therapeutic Goods Administration (TGA) created a pharmacist-only category, called Schedule 3, for CBD products with a maximum daily dose of 150 mg.1 The conditions include:23

  • adults only
  • oral products only (no vapes and no creams)
  • the product must be approved by the TGA and entered on the Australian Register of Therapeutic Goods
  • label warnings against use in pregnancy and breastfeeding.

At the time of the decision, no product met these conditions.2 That is still the case. In August 2025 the TGA said no complete application for a Schedule 3 CBD product had been submitted or evaluated, and as of November 2026 none has been registered.4 See Can you buy CBD over the counter in Australia?. For how the schedules fit together, see Schedule 3, 4 and 8 explained.

Why is the limit 150 mg a day?

The limit is a safety line. The TGA’s interim decision proposed a ceiling of 60 mg a day. The final decision raised it to 150 mg a day after a further safety review, public submissions and advice from its scheduling committee.1 The TGA’s safety review in April 2020 had concluded that low-dose CBD had an acceptable safety and tolerability profile.3

None of this says 150 mg a day is effective. Researchers at the University of Sydney’s Lambert Initiative said in 2020 that the 60 mg figure then on the table may be too low to benefit patients, and that benefits in studies were usually seen at 300 to 1,500 mg a day.5

What did trials at or below 150 mg a day find?

These are human trials of CBD at doses that fit under the Schedule 3 ceiling.

Condition Dose and form Who and how long Result
Insomnia 150 mg under the tongue, 1 hour before bed 30 adults with moderate to severe insomnia, 2 weeks No difference from placebo in insomnia severity, time to fall asleep or time awake in the night. Measured sleep efficiency and self-rated wellbeing were higher on CBD6
Hand osteoarthritis and psoriatic arthritis 20 to 30 mg/day, synthetic CBD 129 adults analysed, 12 weeks Pain difference from placebo was 0.23 mm on a 100 mm scale. No effect on sleep, depression or anxiety scores7
Irritable bowel syndrome 50 mg chewing gum, as needed 32 women No significant difference in pain from placebo8
Parkinson’s disease (movement) 75 mg/day (a 300 mg/day group was also tested) 21 people No difference in movement scores at either dose9
Parkinson’s disease (thinking and memory) 26 mg/day under the tongue 12 weeks Safe, but no difference between groups on the main outcome10
Muscle damage after hard exercise 150 mg/day for 3 days Study cited in a later sports trial No effect on muscle damage11
Alcohol craving 150 mg/day hemp-derived CBD, as full-spectrum or broad-spectrum extract 44 people, pilot study The full-spectrum group had a larger drop in craving than the broad-spectrum or placebo groups. The sample was small12

The insomnia trial is the most direct test, because it was run in Australia at exactly the Schedule 3 ceiling. Its authors concluded that 150 mg of CBD “was similar to placebo regarding most sleep outcomes”.6

The one positive result, for alcohol craving, comes from a small pilot of a full-spectrum extract. Full-spectrum extracts contain other cannabis compounds, which can include traces of THC, so it is not a clean test of CBD alone. See full spectrum vs broad spectrum vs isolate.

What do reviews of low doses say?

The most thorough look is a 2023 review by Lambert Initiative researchers of oral CBD at 400 mg a day or less. It found that benefits “became more clearly evident at doses ≥300 mg”.13 That is twice the Schedule 3 ceiling.

Writing in Australian Prescriber in 2020, the same group said that very low doses, about 5 to 25 mg, have little evidence of health benefit.14

Other trials point the same way. In a trial for cannabis use disorder, the 200 mg a day group was dropped as ineffective while 400 and 800 mg a day reduced cannabis use.15 In a public-speaking anxiety study, a 300 mg dose reduced anxiety compared with placebo, while the lower and higher doses tested did not.16 A 2025 trial reported that 150, 300 or 600 mg had no effect on fear and panic symptoms in a breathing challenge.17

More is not always better either. Pain trials at 400 mg and 600 mg were just as negative as the trial at 20 to 30 mg.1819 The honest summary is that low doses are poorly supported, and for some uses no dose is supported. Check the page for your condition, starting with how we grade the evidence.

Why do so many people take low doses anyway?

A few reasons are worth knowing about.

  • Price. CBD is sold by the milligram, so a 300 mg daily dose costs many times what a 25 mg dose does. See how much CBD costs in Australia.
  • Overseas norms. In the UK, the Food Standards Agency advises healthy adults to limit CBD from food supplements to 10 mg a day, down from an earlier 70 mg, mainly because of liver effects and sleepiness with long-term use.20 That is advice about safety, not about what works.
  • Expectation. People on placebo often improve too. In the 12-week arthritis trial above, 21% of the placebo group had a large drop in pain, against 22% on CBD.7 This is why placebo-controlled results matter more than personal reports.

Is low-dose CBD safer?

It looks well tolerated, with some gaps.

  • The 2023 review found that raising the dose from 60 to 400 mg a day did not appear to increase adverse effects.13
  • In the Australian insomnia trial, 150 mg a night did not impair thinking the next day. Dry mouth was more common on CBD.21
  • Rises in liver enzymes (blood markers of liver stress) are clearly documented at higher doses. 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 significant rises, against none on placebo.22 Data at 150 mg a day or less are sparse, which is different from showing there is no effect. See CBD and the liver.
  • The UK regulator says interactions with medicines cannot be ruled out below 70 mg a day, and advises people on prescription medicines not to take CBD supplements without medical advice.20 See CBD drug interactions.
  • Schedule 3 products must carry the warnings “Do not use if pregnant or likely to become pregnant” and “Do not use if breastfeeding or planning to breastfeed”.23 See CBD in pregnancy and breastfeeding.

What this means if you are considering CBD

A dose that is legal to sell without a prescription is not the same as a dose that has been shown to work. If you are thinking about CBD for a health problem, a GP can tell you whether there is evidence for that problem at any dose, and what the proven options are. See talking to your GP about CBD and, for the wider picture on doses, the CBD dosage guide.

Footnotes

  1. Therapeutic Goods Administration. Notice of final decision to amend the Poisons Standard: cannabidiol. https://tga.gov.au/node/284859 ↩ ↩2

  2. Therapeutic Goods Administration. Notice of interim decisions on proposed amendments to the Poisons Standard, June 2020 meetings: 4.1 Cannabidiol. https://www.tga.gov.au/resources/publication/scheduling-decisions-interim/notice-interim-decisions-proposed-amendments-poisons-standard-acms-and-joint-acms-accs-meetings-june-2020/41-cannabidiol-private-application-and-cannabidiol-delegate-initiated ↩ ↩2

  3. Retail Pharmacy magazine. TGA announces OTC access for low-dose CBD (news report of the TGA decision). https://retailpharmacymagazine.com.au/tga-announces-otc-access-for-low-dose-cbd/ ↩ ↩2

  4. Therapeutic Goods Administration. Consultation paper: reviewing the safety and regulatory oversight of unapproved medicinal cannabis products, August 2025. https://consultations.tga.gov.au/medicines-regulation-division/test-soms/user_uploads/final---consultation-paper---medicinal-cannabis-review---august-2025.pdf ↩

  5. University of Sydney. Australia unprepared for over-the-counter medical cannabis sales, 16 September 2020. https://www.sydney.edu.au/news-opinion/news/2020/09/16/Australia-unprepared-for-over-the-counter-medical-cannabis-sales.html ↩

  6. 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/ ↩ ↩2

  7. 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

  8. Randomised crossover trial of cannabidiol chewing gum in irritable bowel syndrome (PubMed record). https://pubmed.ncbi.nlm.nih.gov/33998882/ ↩

  9. Chagas MHN, et al. Effects of cannabidiol in the treatment of patients with Parkinson’s disease: an exploratory double-blind trial, 2014. https://pubmed.ncbi.nlm.nih.gov/25237116/ ↩

  10. Randomised controlled trial of sublingual cannabidiol in Parkinson’s disease (PubMed record). https://pubmed.ncbi.nlm.nih.gov/40267585/ ↩

  11. Sahinovic A, et al. Effects of cannabidiol on exercise physiology and bioenergetics: a randomised controlled pilot trial. Sports Medicine Open, 2022 (the 150 mg study is cited in its introduction). https://pmc.ncbi.nlm.nih.gov/articles/PMC8891421 ↩

  12. Pilot randomised trial of full-spectrum and broad-spectrum hemp-derived cannabidiol in alcohol use disorder. https://pmc.ncbi.nlm.nih.gov/articles/PMC12066606 ↩

  13. 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/ ↩ ↩2

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

  15. Freeman TP, et al. Cannabidiol for the treatment of cannabis use disorder: a phase 2a, double-blind, placebo-controlled, randomised, adaptive Bayesian trial. Lancet Psychiatry, 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7116091/ ↩

  16. Cannabidiol presents an inverted U-shaped dose-response curve in a simulated public speaking test (journal article). https://pmc.ncbi.nlm.nih.gov/articles/PMC6781714/ ↩

  17. PsyPost. Cannabidiol has no effect on fear and panic symptoms, study finds (news report of a 2025 double-blind trial). https://psypost.org/cannabidiol-has-no-effect-on-fear-and-panic-symptoms-study-finds ↩

  18. 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 ↩

  19. 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/ ↩

  20. UK Government. Provisional cannabidiol (CBD) acceptable daily intake: lay summary. https://www.gov.uk/government/publications/provisional-cannabidiol-cbd-acceptable-daily-intake-adi/lay-summary ↩ ↩2

  21. Cognition and next-day function results from the Australian trial of 150 mg nightly cannabidiol for insomnia (journal article). https://pmc.ncbi.nlm.nih.gov/articles/PMC11063694/ ↩

  22. 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 ↩

  23. Australian Government. Therapeutic Goods (Poisons Standard, October 2026) Instrument 2026, Appendix F (warning statements for cannabidiol in Schedule 3). https://www.legislation.gov.au/F2026L01327/asmade/2026-09-30/text/original/pdf ↩

Common questions

Why is the over-the-counter CBD limit 150 mg a day?

The limit is a safety threshold. The TGA first proposed 60 mg a day, then raised it to 150 mg a day after a further safety review, public submissions and committee advice. The decision was not based on evidence that 150 mg a day is an effective dose for any condition.

Is 150 mg of CBD enough to do anything?

The evidence is weak. In an Australian trial, 150 mg a night was similar to placebo for insomnia on most measures. A review of oral doses up to 400 mg a day found benefits were more clearly evident at 300 mg a day or more, though pain trials at 400 and 600 mg also found no benefit.

Do 10 to 50 mg doses of CBD work?

There is little evidence that they do. Australian researchers writing in Australian Prescriber said very low doses of about 5 to 25 mg have little evidence of health benefit, and a 12-week trial of 20 to 30 mg a day for arthritis pain found no difference from placebo.

Is low-dose CBD safe?

Low doses appear well tolerated in the short trials done so far. That is not the same as proven safe for everyone. UK regulators say interactions with medicines cannot be ruled out even below 70 mg a day, and the pharmacist-only rules exclude use in pregnancy and breastfeeding.

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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