Last updated 3 August 2026 · Originally published 24 May 2022
CBN is sold as the sleep cannabinoid. Gummies, tinctures and softgels all lean on the same story: aged cannabis makes you drowsy, aged cannabis is high in CBN, therefore CBN makes you sleepy.
It is a tidy story, and for most of the past decade it rested on almost nothing. That is finally starting to change — though not quite in the way the packaging suggests.
At a glance
- CBN forms mainly as THC breaks down. Fresh cannabis generally contains only trace amounts.
- Its sleep reputation began with folklore about aged cannabis and weak early evidence involving powerful sedatives.
- A 2024 rat study found CBN changed sleep architecture and increased total sleep — but at doses and by methods that do not resemble retail products.
- Human evidence is mixed. Trials have found possible improvements in night-time awakenings and some other measures, but several primary outcomes were not met.
- Most retail products also contain CBD, THC, melatonin or terpenes, making it hard to know whether CBN is contributing anything.
- CBN is promising enough to study, and not proven enough to deserve its reputation as a reliable sleep aid.
What CBN actually is
Cannabinol was the first cannabinoid ever identified, back in 1896. It is not something the plant produces directly. THC degrades into CBN over time through exposure to air, heat and light — which is why aged cannabis is high in it, while fresh cannabis generally contains only trace amounts.
A United Nations analysis found that cannabis stored at room temperature for four years lost more than 40% of its THC, while its CBN concentration increased.[1]
CBN is much less intoxicating than THC. Most human studies have found little in the way of a conventional cannabis high, although high doses can still produce noticeable drug effects.[2]
Where the sleep story came from
Two sources, and neither is what you would want under a product claim.
The first is folklore. Aged cannabis has long been said to feel sleepier and flatter than fresh cannabis, and since aged cannabis contains more CBN, CBN got the credit. Ethan Russo, the neurologist best known for popularising the entourage effect, has pointed out the obvious problem: ageing changes far more than CBN. THC levels fall and the terpene profile shifts, leaving plenty of possible explanations besides CBN.
The second is a marketing claim. The cannabis testing company Steep Hill published a statement that 2.5–5 mg of CBN produced sedation comparable to 5–10 mg of diazepam. It travelled everywhere. Steep Hill later replaced it with something rather different: that CBN had initially been reported as promising for insomnia, but that with a few small trials, sedative qualities had not been observed.
The correction never travelled as far as the claim.
What the early animal studies actually showed
Early animal evidence was not quite what modern marketing makes it sound like. In a 1974 study, CBN modestly prolonged sleep produced by pentobarbital, a powerful barbiturate. That suggests an interaction with a sedative; it does not show that CBN independently puts an animal — or a person — to sleep.
A separate 1995 study went a step further from anything you can buy. It tested chemically modified, halogenated derivatives of CBN in mice, again alongside pentobarbital. Some prolonged barbiturate-induced sleep, but the molecules were not ordinary CBN.
What changed in 2024
Then the picture genuinely improved. Researchers at the University of Sydney’s Lambert Initiative ran the first study to measure CBN’s effect on sleep objectively, using polysomnography in rats.[3]
CBN increased total sleep time, raising both NREM and REM sleep. The effect on NREM sleep was comparable in size to zolpidem, a common prescription sleep drug — though unlike zolpidem, CBN also increased REM sleep. The response was biphasic: sleep was initially suppressed before increasing markedly.
That is the first real objective evidence for the folklore, and it is worth taking seriously. It is also, still, rats.
The same group has now published a placebo-controlled trial in twenty people with diagnosed insomnia, testing single doses of 30 mg and 300 mg with overnight laboratory monitoring.[4] Neither dose significantly improved the trial’s primary outcome: the amount of time participants spent awake after first falling asleep.
The 300 mg dose did shorten the time taken to fall asleep, increase stage 2 NREM sleep, improve subjective sleep quality and reduce some signs of overnight arousal. Those are encouraging secondary findings, but one night in twenty people is a proof of concept rather than evidence that an ordinary CBN supplement treats insomnia — and 300 mg is far above most retail doses.
What the human trials found
A much larger 2024 trial produced a modestly more positive result. More than 800 participants received 25 mg, 50 mg or 100 mg of purified CBN, or placebo, for several weeks.[5] The 50 mg dose performed significantly better than placebo on a self-reported sleep-disturbance scale; findings for 25 mg and 100 mg were weaker and depended on the analysis used.
That is evidence of a possible effect rather than a clear demonstration. Sleep was measured by questionnaire rather than in a laboratory, participants did not necessarily have diagnosed insomnia, and the study tested a proprietary product supplied by its manufacturer.
Another 2024 trial offers perhaps the clearest picture of the uncertainty. Nearly 300 poor sleepers took 20 mg of CBN alone, CBN with different amounts of CBD, or placebo, for seven nights.[6] CBN did not significantly improve the study’s primary measure of overall sleep quality. It did reduce night-time awakenings by about half an awakening per night, and modestly reduced overall sleep disturbance. Adding CBD did not improve the effect.
The problem with CBN products
Here is the practical difficulty. Almost no commercial “CBN for sleep” product is CBN alone.
Typical formulations combine CBN with CBD, often with a small amount of THC, frequently with melatonin, and sometimes with terpenes such as myrcene and linalool, which are often marketed as calming. A 2025 crossover trial of one such supplement — 3 mg THC, 6 mg CBN, 10 mg CBD and a terpene blend — did find improvements in sleep latency, duration and overall quality against placebo.[7]
That is a real result. But it tells you the combination worked, and gives no way to know whether the CBN contributed anything. If a product contains melatonin and THC, both of which have their own effects on sleep, attributing the outcome to CBN is a marketing decision rather than a scientific one.
Russo’s blunter version: pure CBN, in his view, is not particularly sedating.
So should you try it?
The honest position is that CBN is more interesting than it was two years ago and less proven than the packaging implies.
If you want to try it, a few things are worth knowing.
Read the full ingredient list. If it contains melatonin, any benefit cannot automatically be attributed to CBN — and melatonin on its own is usually much cheaper. If there is THC, expect the effects and the caveats that come with THC.
Expect to pay. CBN is expensive to produce, because it either requires degrading THC or converting other cannabinoids through additional processing.
Watch for morning grogginess, which can occur particularly with combination products — though controlled CBN trials have not consistently found more side effects than placebo.
Do not mix it with alcohol or other sedatives. Combining sedating substances is where the real risk sits.
Check the lab report. Rules for CBN vary by jurisdiction and can depend on how the cannabinoid was produced and how the product is sold. Testing across the cannabinoid market also routinely finds products whose labels do not accurately reflect their contents.
None of this is medical advice. Persistent insomnia is worth discussing with a doctor: it has effective treatments, and cognitive behavioural therapy for insomnia in particular has strong evidence behind it.
For more on cannabinoids generally, see our guide to CBD and what the research actually shows, or browse Sleep.
References
- Ross SA, ElSohly MA. CBN and Δ9-THC concentration ratio as an indicator of the age of stored marijuana samples. United Nations Office on Drugs and Crime Bulletin on Narcotics. 1997.
- Huestis MA. Pharmacokinetics and metabolism of the plant cannabinoids, Δ9-tetrahydrocannabinol, cannabidiol and cannabinol. Handbook of Experimental Pharmacology. 2005;168:657–690. doi:10.1007/3-540-26573-2_23
- Arnold JC, Occelli Hanbury-Brown CV, Anderson LL, et al. A sleepy cannabis constituent: cannabinol and its active metabolite influence sleep architecture in rats. Neuropsychopharmacology. 2025;50:586–595. doi:10.1038/s41386-024-02018-7
- Lavender I, McCartney D, Marshall N, 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
- Kolobaric A, Saleska J, Hewlings SJ, et al. A randomized, double-blind, placebo-controlled trial to assess the effectiveness and safety of melatonin and three formulations of proprietary CBN for improving sleep. Pharmaceuticals. 2024;17(8):977. doi:10.3390/ph17080977
- Bonn-Miller MO, Feldner MT, Bynion TM, et al. A double-blind, randomized, placebo-controlled study of the safety and effects of CBN with and without CBD on sleep quality. Experimental and Clinical Psychopharmacology. 2024;32(3):277–284. doi:10.1037/pha0000682
- Hausenblas H, Hooper S, Lynch T. Effectiveness of a cannabinoids supplement on sleep and mood in adults with subthreshold insomnia: a randomized double-blind placebo-controlled crossover pilot trial. Health Science Reports. 2025;8:e70481. doi:10.1002/hsr2.70481
About this article
Substantially rewritten in August 2026. This update adds the 2024 Sydney research measuring CBN’s effects on sleep objectively for the first time, the human trials published since — including the CUPID insomnia trial published in February 2026 — and the origins of CBN’s reputation as a sleep aid.
