The evidence is thin and points in different directions. Tolerance means needing more of a drug to get the same effect. One effect of CBD, a drop in blood pressure, faded within 7 days of daily dosing, while seizure reductions in a long-term epilepsy follow-up held for three years.12 For most other uses, tolerance has not been properly studied.
What has been measured?
| Effect studied | Who and what dose | What happened over time |
|---|---|---|
| Resting blood pressure | 26 healthy men, 600 mg a day for 7 days | The drop seen after a first dose was lost with repeated dosing1 |
| Drop seizures in Lennox-Gastaut syndrome | Long-term follow-up on prescription CBD, no placebo group | Median reductions of 48 to 71% were maintained through 156 weeks2 |
The epilepsy follow-up had no comparison group, so it cannot prove how large the effect was.2
What should you do if it seems to work less well?
Talk to your prescriber. Do not raise the dose yourself. The Therapeutic Goods Administration’s assessment of the registered CBD medicine identified higher dose as a risk factor for liver abnormalities.3 Also check whether anything else has changed. Food alone can change the amount of CBD absorbed several-fold, so a new routine can look like a change in effect.4 See should you take CBD with food?
Is there withdrawal when you stop?
Studies have not found it. Adults who took 1,500 mg a day for 28 days showed no signs or symptoms of withdrawal over 6 weeks of follow-up, and the US prescribing information concludes that CBD “likely does not produce physical dependence”.4 The World Health Organization found “no case reports of abuse or dependence relating to the use of pure CBD”.5
That study lasted 28 days and tested pure CBD. Products that also contain THC are a different matter.
Can you stop suddenly?
Not if you take CBD for epilepsy. The prescribing information says the dose should be decreased gradually, because stopping abruptly risks more seizures.4 The specialist sets the schedule.
For anyone, stopping CBD can change the blood levels of other medicines, such as warfarin, clobazam and tacrolimus. Reviewers advise monitoring warfarin when starting, stopping or changing the dose.6 Tell your prescriber and pharmacist before you stop.
Is needing more a sign it is working?
No. If nothing changes when CBD is stopped, it may not have been doing much. Placebo-controlled trials of CBD for pain and insomnia have mostly found it no better than a dummy treatment.78
Read the full guide: stopping CBD: tolerance, withdrawal and tapering.
Footnotes
-
Systematic review of randomised trials of oral cannabidiol and blood pressure in adults (summarising Sultan et al., 2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC13531894/ ↩ ↩2
-
Long-term cannabidiol treatment in Lennox-Gastaut syndrome: open-label extension results. Epilepsia (copy hosted by University College London). https://discovery.ucl.ac.uk/id/eprint/10126054/1/epi.16878.pdf ↩ ↩2 ↩3
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Therapeutic Goods Administration. Australian Public Assessment Report for cannabidiol (Epidyolex). https://www.tga.gov.au/sites/default/files/auspar-cannabidiol-210115.pdf ↩
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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 ↩ ↩2 ↩3
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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 ↩
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Systematic review of drug interactions with cannabidiol and other cannabinoids. https://pmc.ncbi.nlm.nih.gov/articles/PMC11167383/ ↩
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Moore RA, 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 ↩
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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/ ↩
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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