Cannabinol (CBN), a mildly psychoactive cannabinoid marketed as a natural sleep aid, did not significantly reduce wake after sleep onset (WASO) in a rigorous randomized controlled trial. However, the higher dose tested improved several secondary measures of sleep quality.
Lead
CBN has gained popularity as a non-prescription sleep supplement, often sold in oils, gummies, and capsules with claims that it promotes restful sleep. Despite widespread consumer use, rigorous clinical evidence has been lacking. A new randomized, double-blind, placebo-controlled crossover trial from researchers at the Woolcock Institute of Medical Research and the University of Sydney provides the most controlled test to date of CBN’s effects on objectively measured sleep in people with diagnosed insomnia.
What they found
Twenty adults (17 female, 3 male; mean age 42 years) with physician-diagnosed insomnia disorder and Insomnia Severity Index scores of 15 or higher each received three single-night interventions in random order: a 30 mg dose of CBN, a 300 mg dose, or a matched placebo, separated by two-week washout periods. Overnight polysomnography measured WASO as the primary endpoint.
Neither dose produced a statistically significant reduction in WASO. The 300 mg dose yielded a mean reduction of 6.3 minutes (95% CI: -18.2 to +5.5; p = 0.29), and the 30 mg dose a 4.0 minute reduction (95% CI: -15.9 to +7.9; p = 0.50). The confidence intervals were wide and crossed zero, consistent with no true effect on this primary outcome.
However, the 300 mg dose did produce improvements on several secondary sleep measures. It significantly increased NREM stage 2 sleep duration (p = 0.03, Cohen’s dz = 0.54), reduced sleep onset latency (p = 0.004, dz = -0.74), lowered EEG arousal indices (p = 0.02, dz = -0.65), and improved subjective sleep quality ratings (p = 0.005, dz = 0.56). The 30 mg dose showed no significant effects on any secondary measure.
The study was registered at ClinicalTrials.gov under identifier NCT05344170 and enrolled participants from August 2022 to September 2023.
A total of 247 mild-to-moderate adverse events were recorded across all study arms including placebo, with no serious adverse events reported. The most commonly reported effects were sedation, dizziness, and gastrointestinal discomfort, though these occurred at comparable rates across active treatment and placebo conditions.
Why it matters
This trial addresses a significant gap. CBN is widely available in consumer sleep products but until now has not been tested against placebo in a controlled laboratory setting with objective sleep measurement in an insomnia population. The negative primary result is important: a 6-minute improvement in WASO is clinically negligible, and the confidence intervals exclude any meaningful benefit on the core insomnia symptom of staying asleep. The secondary signal on sleep onset and sleep depth warrants further investigation, but does not establish CBN as an effective insomnia treatment.
Limits
The sample was small (n = 20) and predominantly female. The single-night design captures only acute effects and cannot assess tolerance, withdrawal, or sustained efficacy. The crossover design with a two-week washout may be insufficient for a long half-life cannabinoid. The high rate of mild-to-moderate adverse events across all arms is notable and complicates interpretation of subjective outcomes.
Bottom line
CBN at 30 mg or 300 mg did not improve wake after sleep onset in adults with insomnia disorder. The higher dose improved some secondary parameters including sleep onset latency and subjective sleep quality, but these findings are preliminary and require replication in larger, longer-term trials before clinical recommendations can be made.
Source
Lavender IG, Marshall NS, McCartney D, et al. Cannabinol for acute treatment of insomnia disorder in a randomized placebo-controlled crossover trial. Journal of Sleep Research. 2026; e70284. doi: 10.1111/jsr.70284