CBD/THC Capsules Did Not Reduce Essential Tremor in a Small Controlled Trial | Research

The takeaway

A double-blind, placebo-controlled crossover trial of oral THC (5mg) and CBD (100mg) capsules found no signal of efficacy for reducing essential tremor, despite anecdotal reports of cannabis helping.

People with essential tremor considering cannabis and clinicians advising patients about tremor treatment options.

No signal of efficacy on any primary or secondary endpoint in this controlled trial

What the researchers found

Among seven enrolled participants (five completers), intent-to-treat analyses found no significant effects on the primary endpoint (tremor amplitude via digital spiral assessment) or any secondary endpoints. One participant withdrew due to a serious adverse event, and one could not tolerate the lowest dose. The remaining five tolerated the medication well.

Why it matters

Essential tremor is the most common movement disorder with limited treatment options. Anecdotal reports of cannabis helping are widespread, but this is the first controlled trial to test the claim. The negative result, while preliminary, does not support those anecdotes.

The numbers in context

13 screened, 7 enrolled, 5 completed. Maximum dose: 3 capsules/day (15mg THC, 300mg CBD). No significant effects on primary or secondary endpoints. 1 serious adverse event leading to withdrawal. 1 participant could not tolerate lowest dose. 5 of 7 tolerated the medication.

How the study worked

Phase Ib/II double-blind, placebo-controlled, crossover pilot trial. Participants with essential tremor were randomized to pharmaceutical-grade THC 5mg/CBD 100mg capsules or placebo with dose titration every 2-3 days to a maximum of 3 capsules daily. Two-week treatment periods with three-week washout.

What this study cannot tell us

Very small sample (7 enrolled, 5 completers). Short treatment duration. Only one THC:CBD ratio tested. Oral administration may not replicate the effects reported by people who smoke or vaporize cannabis. Underpowered to detect modest effects.

How to read the evidence

Preliminary: very small pilot trial (5 completers) that was underpowered, though well-designed with placebo control and crossover.

When this study was published

2025 study.

The bigger picture

This adds to a pattern where controlled trials fail to confirm anecdotal cannabis benefits for specific conditions. Whether different formulations, doses, or cannabinoid ratios might work for essential tremor remains an open question.

Questions still open

Would higher THC doses or different THC:CBD ratios show different results? Could the anecdotal reports reflect placebo effects or temporary anxiolytic benefits? Should larger trials still be pursued?

Common questions

Should people with essential tremor try cannabis?

This controlled trial found no evidence of benefit for a pharmaceutical-grade THC/CBD formulation. While it was a small study, it does not support the anecdotal claims.

Was the cannabis well tolerated?

Five of seven participants tolerated the medication well. One had a serious adverse event and one could not tolerate even the lowest dose.

Read the original research

Double-Blind, Randomized, Placebo-Controlled, Crossover Study of Oral Cannabidiol and Tetrahydrocannabinol for Essential Tremor.

Tremor and other hyperkinetic movements (New York, N.Y.), 15, 14

View on PubMed ↗Publisher’s paper ↗

Citation

Longardner, Katherine; Shen, Qian; Castellanos, Francisco X; Tang, Bin; Gandhi, Rhea; Wright, Brenton A; Momper, Jeremiah D; Nahab, Fatta B. (2025). Double-Blind, Randomized, Placebo-Controlled, Crossover Study of Oral Cannabidiol and Tetrahydrocannabinol for Essential Tremor.. Tremor and other hyperkinetic movements (New York, N.Y.), 15, 14. https://doi.org/10.5334/tohm.1005