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CBD for Parkinson's disease

Small trials have not found that CBD improves the movement symptoms of Parkinson's disease, and trials of CBD with THC have also been negative.

Facts checked 13 November 20264 min readHow we research
Not enough evidence

The few trials are small. CBD alone at 26 to 300 mg a day did not improve movement or thinking scores, and two trials of CBD combined with THC found no benefit.

How we grade evidence

Trials have not shown that CBD improves the movement symptoms of Parkinson’s disease. The studies of CBD alone are small, and the larger studies used CBD combined with THC and found no benefit. There is no evidence that CBD slows the disease.

What the research shows

Trial Product People Result
Chagas 2014 CBD alone, 75 or 300 mg a day 21 No difference in movement scores. Better quality-of-life score at 300 mg.
Thai trial CBD alone, 26 mg a day under the tongue, 12 weeks Not confirmed No difference on the main thinking and memory outcome.
Liu 2024 CBD with a small amount of THC 61 No benefit for movement or other symptoms.
2026 pain trial CBD and THC oil 101 No significant difference from placebo for pain.

Chagas and colleagues (2014) compared placebo, CBD 75 mg a day and CBD 300 mg a day in 21 people with Parkinson’s disease. Movement scores, measured on the standard rating scale (UPDRS), did not differ between groups. A quality-of-life questionnaire (PDQ-39) was better in the 300 mg group, with a P value of 0.05, which is right on the usual borderline for a chance finding.1 With only 21 people split three ways, this result needs repeating before it can be relied on.

A Thai trial gave CBD alone at 26 mg a day under the tongue for 12 weeks. The main outcome, a test of thinking and memory, showed no difference between CBD and placebo.2

Liu and colleagues (2024) tested a product that was mostly CBD with a small amount of THC in 61 people. It showed no benefit for movement symptoms or non-movement symptoms.3

A 2026 trial of a CBD and THC oil for Parkinson’s pain in 101 people found no significant difference from placebo.4

Laboratory and animal studies suggest cannabinoids may protect nerve cells, but this has not been shown in people. See CBD and brain health.

What doses were tested

CBD alone has been tested at 26 mg, 75 mg and 300 mg a day.12 None improved movement. The 75 mg dose, which is within the 150 mg a day limit for pharmacist-only (Schedule 3) CBD in Australia, showed no benefit on any measure.15

Higher doses have not been tested in a controlled Parkinson’s trial that we could find, so it is unknown whether they would do any better.

What Australian medical bodies say

No Australian medical body recommends CBD for Parkinson’s disease.

  • The TGA says medicinal cannabis should be considered only when registered medicines have been tried and have failed. The clinical evidence in its guidance dates to 2017.6
  • RACGP (the GPs’ college) describes the overall evidence as “limited and inconclusive” and does not recommend or encourage medicinal cannabis.7
  • As of November 2026, only two cannabis medicines are registered in Australia, and neither is for Parkinson’s disease.8

See what Australian medical bodies say about CBD.

Risks to know about

  • Sleepiness. Drowsiness is among the most common side effects of CBD, and it adds to the effect of other sedating medicines.9 Daytime sleepiness matters for anyone who is already unsteady on their feet.
  • Interactions. CBD blocks several liver enzymes that process other medicines.9 People with Parkinson’s disease often take several medicines, and no trial has checked CBD against them. See CBD drug interactions.
  • Liver. CBD can raise liver enzymes, more often at higher doses.9 See CBD and the liver.
  • THC. Products containing THC bring extra risks and can produce a positive roadside drug test. The TGA’s guidance, written with THC in mind, says patients should be told they are not able to drive while being treated.6 See CBD and driving.

Our page on CBD for older adults covers these issues in more detail.

If you are considering it

  • Raise any treatment questions with your neurologist or GP first, and do not change your Parkinson’s medicines on your own.
  • Ask which symptom the treatment is aimed at, and what the trials found for that symptom.
  • Ask whether the product contains THC.
  • Have a pharmacist check your whole medicine list for interactions.
  • If any new treatment is prescribed, agree on a review date. TGA guidance says treatment should be stopped if benefit has not been shown.6

See talking to your GP about CBD for questions to ask.

Footnotes

  1. 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/ ↩ ↩2 ↩3

  2. Randomised controlled trial of sublingual cannabidiol in Parkinson’s disease (Thailand). https://pubmed.ncbi.nlm.nih.gov/40267585/ ↩ ↩2

  3. Liu Y et al. Randomised trial of cannabidiol with low-dose THC in Parkinson’s disease, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11102313/ ↩

  4. Randomised controlled trial of CBD/THC oil for pain in Parkinson’s disease, 2026. https://pubmed.ncbi.nlm.nih.gov/42563548/ ↩

  5. Therapeutic Goods Administration. Final decision on the scheduling of low-dose cannabidiol, 2020. https://tga.gov.au/node/284859 ↩

  6. 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 ↩ ↩2 ↩3

  7. Royal Australian College of General Practitioners. Medical cannabis position statement (2019 update). https://www.racgp.org.au/advocacy/position-statements/view-all-position-statements/clinical-and-practice-management/medical-cannabis ↩

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

  9. Epidiolex (cannabidiol) US prescribing information, DailyMed, revised 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩ ↩2 ↩3

Common questions

Does CBD help Parkinson's tremor?

Trials have not shown that it does. In a trial of 21 people, CBD at 75 mg or 300 mg a day made no difference to movement scores compared with placebo. A later trial of CBD with a small amount of THC in 61 people also found no benefit for movement symptoms.

Does CBD help with Parkinson's pain or sleep?

A 2026 trial of a CBD and THC oil for Parkinson's pain in 101 people found no significant difference from placebo. No controlled trial of CBD alone for sleep in Parkinson's disease was found in our research.

Is CBD safe to take with Parkinson's medicines?

No trial has tested this directly. CBD slows several liver enzymes that break down other medicines, so it can change their levels, and it can cause sleepiness. Your neurologist or pharmacist should check your full medicine list first.

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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