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CBD myths and misleading claims

Fifteen common claims about CBD checked against the evidence, from "proven for pain" and "no side effects" to "it turns into THC in your stomach".

Facts checked 13 November 20269 min readHow we research

Many of the things commonly said about CBD are not supported by the research, and a few of the fears about it are not supported either. This page checks fifteen common claims against the evidence. Each one links to a fuller page.

A note on why myths spread. Most claims trace back to a real study, often in cells or animals, or a small study without a placebo group. Our guide to how we grade evidence explains why those count for little.

Myths about what CBD does

“CBD is proven to relieve pain”

A 2024 review found 16 randomised trials of pharmaceutical-grade CBD that measured pain. In 15 of them CBD was no better than placebo.1 The International Association for the Study of Pain does not endorse the general use of cannabinoids for pain, because high-quality evidence is lacking.2 See CBD for chronic pain.

“CBD helps arthritis”

Two placebo-controlled trials have tested this. One used 20 to 30 mg a day for hand osteoarthritis and psoriatic arthritis and found no difference in pain.3 The other used 600 mg a day for knee osteoarthritis. It also found no benefit, and liver enzyme rises were more common with CBD.4 See CBD for arthritis.

“CBD is a proven sleep aid”

In an Australian trial of 30 people with insomnia, 150 mg of CBD nightly was similar to placebo on most sleep measures.5 A 2025 analysis found that cannabinoids improved self-rated sleep quality modestly, “particularly non-CBD formulations”.6 See CBD for sleep and insomnia.

“CBD is proven for anxiety”

The best-known positive results are single-dose laboratory studies at 300 to 600 mg and one youth study with no placebo group. When 21 placebo-controlled trials were pooled in 2025, the effect of CBD on anxiety disorders was not statistically significant.7 A 2026 analysis of all cannabinoids in The Lancet Psychiatry found no significant effect on anxiety and concluded that their routine use for mental disorders “is currently rarely justified”.8 See CBD for anxiety.

“CBD treats or cures cancer”

There is no clinical trial evidence that it does. The anti-tumour findings come from cell and animal studies.9 In an Australian trial in people with advanced cancer, CBD oil added no benefit over palliative care alone, even for symptoms.10 See CBD and cancer.

“A few drops is all you need”

Most trials used large doses. A review by Australian researchers of oral doses up to 400 mg a day found benefits “became more clearly evident” at 300 mg a day or more.11 The epilepsy doses work out to roughly 700 to 1,400 mg a day for a 70 kg adult. Evidence at those doses does not transfer to 10 or 20 mg. See Does low-dose CBD work?

“Full spectrum works better because of the entourage effect”

This is a hypothesis, not a finding. A 2023 scoping review found limited evidence for the entourage effect and warned against promoting it as proven.12 Laboratory studies of terpenes at cannabinoid receptors have been mostly negative.13 See the entourage effect.

Myths about safety

“CBD is natural, so it has no side effects”

Sleepiness, diarrhoea, reduced appetite and raised liver enzymes are all documented in trials.14 In a US Food and Drug Administration study, 5.6% of healthy adults taking about 350 to 400 mg a day had significant liver enzyme rises within four weeks. Nobody on placebo did.15 See CBD side effects and CBD and the liver.

“CBD does not interact with medicines”

It does. CBD slows several liver enzymes that process other medicines. It roughly triples blood levels of the active breakdown product of the epilepsy medicine clobazam, and it raised exposure to the transplant medicine everolimus about 2.5 times.14 A systematic review rated warfarin, valproate, tacrolimus and sirolimus as the highest-risk interactions.16 See CBD drug interactions.

“It is safe in pregnancy because it is natural”

The Therapeutic Goods Administration says medicinal cannabis is not appropriate for women who are pregnant, planning pregnancy or breastfeeding.17 The US Food and Drug Administration “strongly advises against” CBD in pregnancy or while breastfeeding.18 See CBD in pregnancy and breastfeeding.

“What is on the label is what is in the bottle”

Not for unregulated products. In a study of 84 CBD products bought online in the United States, only 31% contained the labelled amount of CBD.19 A 2024 study of 202 products found 74% were off by at least 10%.20 Prescription products are different: when the TGA tested medicinal cannabis products supplied to Australian patients, results were mostly close to the label.21 See Is what is on the label in the bottle?

Myths that overstate the risks

“CBD gets you high” or “CBD is addictive”

Neither is supported. In controlled studies, CBD could not be told apart from placebo on measures of intoxication. The World Health Organization found no case reports of abuse or dependence with pure CBD.22 See Does CBD get you high? and Is CBD addictive?

“CBD turns into THC in your stomach”

This happens in test tubes containing acid. It has not been found in people. A human study concluded that conversion of oral CBD to THC “seems not to occur in humans”.23 The World Health Organization’s review reached the same conclusion.22

Myths about tests and products

“CBD cannot make you fail a drug test”

Half true. After pure CBD, none of 218 urine samples was confirmed positive for THC.24 But full-spectrum products contain THC, and a study of patients taking one for four weeks concluded they may test positive.25 Mislabelled products are a further risk. See Will CBD show up on a drug test?

“Hemp seed oil is CBD oil”

Hemp seed oil is a food pressed from the seeds of the plant. The seed kernel contains only trace amounts of CBD or THC.26 Australian food rules limit the CBD in hemp seed foods, and every product tested in a national survey was within that limit.27 See CBD oil vs hemp seed oil.

Other claims worth a second look

Claim What the evidence shows
“Drops under the tongue absorb far better” No reliable measurement of this exists in people. Taking CBD with a fatty meal has a much larger, proven effect: about four to five times the blood level2814
“CBD cream gets into your joints” Little CBD passes through skin into the body. A randomised pilot of topical CBD found no meaningful effect on muscle soreness2930
“CBN is the sleep cannabinoid” A 2026 review found the evidence “minimal and insufficient to support any clinical recommendation”31
“CBD lowers blood pressure” Seen after a single 600 mg dose in healthy men. The resting effect faded within seven days of repeated dosing32
“CBD treats or prevents COVID-19” A randomised trial of 300 mg a day found CBD did not change the course of the illness33
“Safe for people, so safe for pets” In a six-month study, just over half of dogs given CBD had a rise in the blood enzyme ALP. THC is toxic to dogs3435

More on these: CBD bioavailability, CBD creams and topicals, the other cannabinoids and pet safety.

How to check a claim yourself

  1. Was it tested in people? Cell and animal results rarely carry over.
  2. Was there a placebo group? Without one, improvement cannot be credited to CBD.
  3. Was it CBD alone? Many “cannabis” studies used products containing THC.
  4. What dose? Compare it with the dose in the product being promoted.
  5. Who is making the claim? A seller has a reason to overstate. The rules on promotion are explained on why Australian clinics cannot advertise CBD.

Footnotes

  1. Moore A, Straube S, Fisher E, Eccleston C. Cannabidiol (CBD) products for pain: ineffective, expensive, and with potential harms. Journal of Pain, 2024. https://doi.org/10.1016/j.jpain.2023.10.009 ↩

  2. International Association for the Study of Pain. IASP position statement on the use of cannabinoids to treat pain, 2021. https://www.iasp-pain.org/advocacy/iasp-statements/iasp-position-statement-on-the-use-of-cannabinoids-to-treat-pain ↩

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

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

  5. 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/ ↩

  6. da Silva et al. Meta-analysis of cannabinoids and sleep. Sleep Medicine Reviews, 2025. https://pubmed.ncbi.nlm.nih.gov/40929927/ ↩

  7. Meta-analysis of placebo-controlled trials of cannabidiol for anxiety. Cannabis and Cannabinoid Research, 2025. https://pubmed.ncbi.nlm.nih.gov/40956670/ ↩

  8. Wilson et al. Meta-analysis of cannabinoids for mental disorders. The Lancet Psychiatry, 2026. https://pubmed.ncbi.nlm.nih.gov/41856154/ ↩

  9. Review of clinical data and case reports on cannabinoids as anticancer agents, 2021. https://pubmed.ncbi.nlm.nih.gov/34370591/ ↩

  10. Hardy J, et al. Phase IIb randomized, placebo-controlled, dose-escalating, double-blind study of cannabidiol oil for the relief of symptoms in advanced cancer (MedCan1-CBD). Journal of Clinical Oncology, 2023. https://pubmed.ncbi.nlm.nih.gov/36409969/ ↩

  11. 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/ ↩

  12. Scoping review of the evidence for the cannabis entourage effect, 2023. https://pubmed.ncbi.nlm.nih.gov/37535820/ ↩

  13. Santiago M, et al. Absence of entourage: terpenoids commonly found in Cannabis sativa do not modulate the functional activity of THC at human CB1 and CB2 receptors. Cannabis and Cannabinoid Research, 2019. https://pubmed.ncbi.nlm.nih.gov/31559333/ ↩

  14. Epidiolex (cannabidiol) oral solution, United States prescribing information. DailyMed, National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩ ↩2 ↩3

  15. Florian J, et al. Study of cannabidiol and liver enzymes in healthy adults, JAMA Internal Medicine, 2025 (news release). https://www.eurekalert.org/news-releases/1089832 ↩

  16. Systematic review of drug interactions with cannabidiol and other cannabinoids. PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC11167383/ ↩

  17. Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia: patient information. https://www.tga.gov.au/sites/default/files/guidance-use-medicinal-cannabis-australia-patient-information.pdf ↩

  18. US Food and Drug Administration. What you should know about using cannabis, including CBD, when pregnant or breastfeeding. https://www.fda.gov/consumers/consumer-updates/what-you-should-know-about-using-cannabis-including-cbd-when-pregnant-or-breastfeeding ↩

  19. Bonn-Miller MO, et al. Labeling accuracy of cannabidiol extracts sold online. JAMA, 2017. https://jamanetwork.com/journals/jama/fullarticle/2661569 ↩

  20. Study of label accuracy and contaminants in 202 CBD products bought online, 2024. PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC10982813/ ↩

  21. Therapeutic Goods Administration. Testing of medicinal cannabis products being supplied under SAS in Australia. https://www.tga.gov.au/resources/publication/tga-laboratory-testing-reports/testing-medicinal-cannabis-products-being-supplied-sas-australia ↩

  22. World Health Organization, Expert Committee on Drug Dependence. Cannabidiol (CBD) critical review report, 2018. https://cdn.who.int/media/docs/default-source/controlled-substances/whocbdreportmay2018-2.pdf ↩ ↩2

  23. A conversion of oral cannabidiol to delta-9-tetrahydrocannabinol seems not to occur in humans. Cannabis and Cannabinoid Research, 2017. https://pubmed.ncbi.nlm.nih.gov/28861507/ ↩

  24. Study of urine drug testing after pure CBD and CBD-dominant cannabis, 2019. https://pubmed.ncbi.nlm.nih.gov/31682266/ ↩

  25. Dahlgren MK, et al. Urinary tetrahydrocannabinol after 4 weeks of a full-spectrum, high-cannabidiol treatment. JAMA Psychiatry, 2021. https://pubmed.ncbi.nlm.nih.gov/33146684/ ↩

  26. Andre CM, Hausman JF, Guerriero G. Cannabis sativa: the plant of the thousand and one molecules. Frontiers in Plant Science, 2016. https://www.frontiersin.org/articles/10.3389/fpls.2016.00019/full ↩

  27. Food Standards Australia New Zealand. Survey of low-THC hemp seed foods. https://www.foodstandards.gov.au/science-data/monitoring-safety/survey-of-low-THC-hemp-seed-foods ↩

  28. Millar SA, et al. A systematic review on the pharmacokinetics of cannabidiol in humans. Frontiers in Pharmacology, 2018. https://pubmed.ncbi.nlm.nih.gov/30534073/ ↩

  29. Review of topical and transdermal delivery of cannabidiol. PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC11172078/ ↩

  30. Randomised pilot study of topical CBD for muscle soreness and recovery, 2024. https://pubmed.ncbi.nlm.nih.gov/38980809/ ↩

  31. Review of cannabinol (CBN) in psychiatry, 2026. PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC13373943/ ↩

  32. Systematic review of randomised trials of oral CBD and blood pressure in adults. PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC13531894/ ↩

  33. Published letter discussing the CANDIDATE randomised trial of cannabidiol in mild to moderate COVID-19 (trial registration NCT04467918). PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC9070739/ ↩

  34. Bradley S, et al. Long-term daily feeding of cannabidiol is well-tolerated by healthy dogs. Frontiers in Veterinary Science, 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9533147/ ↩

  35. Study of 223 dogs with THC toxicosis. Journal of the American Veterinary Medical Association, 2024. https://pubmed.ncbi.nlm.nih.gov/38608656/ ↩

Common questions

Does CBD actually work, or is it placebo?

It depends on the condition. CBD clearly beats placebo for seizures in a few rare epilepsies at high prescription doses. For chronic pain, 15 of 16 randomised trials found it no better than placebo. For most other uses the trials are too few or too small to say.

Is CBD completely safe because it is natural?

No. CBD can cause sleepiness, diarrhoea and reduced appetite, can raise liver enzymes and interacts with a number of medicines. Regulators in Australia and the United States advise against using it in pregnancy or while breastfeeding.

Can CBD make you fail a drug test?

Pure CBD does not. Products that contain THC can, and that includes full-spectrum CBD products and mislabelled or contaminated ones. Drug tests look for THC, not CBD.

Is hemp seed oil from the supermarket the same as CBD oil?

No. Hemp seed oil is a food oil pressed from seeds, which contain only trace amounts of cannabinoids. CBD oil is made from flower extract and is a prescription medicine in Australia.

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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