Cannabis Helps People With Insomnia Sleep Longer, but at a Cost

Lots of people reach for cannabis when they can’t sleep. A gummy, a vape, a few drops of oil.

It feels like it works. You get drowsy, you drift off.

But does weed actually help you sleep? And what happens if you use it every night?

The research gives a mixed answer. Cannabinoids may add some sleep time for people with insomnia.

The evidence is weak, though, and regular use can turn into a trap.

Here’s what the trials show, and what they don’t.

Does weed help you sleep?

The short answer: sometimes, a little, and not reliably.

Some trials show cannabinoids can help people with insomnia sleep a bit longer. But the studies are mostly small, short and of varied quality.

The effect also seems to fade with regular use. And when regular users stop, their sleep often gets worse before it gets better.

That’s why sleep doctors don’t treat cannabis as a first-line fix.

It’s easy to see why people try it. The nurse practitioners’ review notes that insomnia “affects over one third of adults”, and standard sleeping pills have their own downsides.

In the UK, the NHS says insomnia “is sometimes treated with cognitive behavioural therapy (CBT)”. It adds that “Sleeping pills are rarely used.”

The NHS explains why. Sleeping pills “can have serious side effects and you can become dependent on them.”

Dependence is a risk worth keeping in mind with cannabis too.

The biggest recent review

What it looked at

In 2026, a team led by the University of Sydney published a major review in The Lancet Psychiatry.

They pooled 54 randomised controlled trials, involving 2,477 people. The trials tested cannabinoids for a range of mental and substance use disorders, including insomnia.

Most participants were men (69%), and the median age was 33. The team searched studies published from 1980 to May 2025.

What it found for sleep

For people with insomnia, “any cannabinoid type led to an increase in sleep time”.

That held whether sleep was tracked by a wearable device or a sleep diary.

Effect sizes like 0.5 are usually read as moderate. But the confidence ranges were wide, especially for sleep diaries.

The big caveat

The authors were blunt about the quality of the evidence.

Across the whole review, “the certainty of evidence for most outcomes was low”. Almost half the trials (24, or 44%) had a high risk of bias.

People taking cannabinoids also had higher odds of side effects. For every seven people treated, about one extra had a side effect, though serious ones weren’t more common.

The authors concluded that routine use of cannabinoids for these conditions “is currently rarely justified.”

A correction to the review, published in August 2026, fixed a figure and some trial counts for other conditions. It didn’t change the sleep results.

CBD, THC and CBN: does the type matter?

Cannabis contains many compounds. The best known are THC, which causes the high, and CBD, which doesn’t.

CBN is a lesser-known one often sold as a sleep aid.

A separate 2026 review, in the Journal of the American Association of Nurse Practitioners, focused on insomnia alone. It looked at medical cannabis for insomnia in adults.

It reported that “Formulations with THC did not show significant improvement in sleep and had higher reports of adverse effects.”

It found CBD doses of 50 to 300 mg and CBN doses of 20 to 100 mg helped sleep in the studies it reviewed. Lower CBD doses only worked with added CBN.

Its advice to clinicians was specific. Patients self-treating should “avoid THC and start with a low dose of CBN or a combination of CBN/CBD.”

That’s a useful signal, but a cautious one. The review’s full data aren’t openly available, and the products tested vary widely.

A newer trial: cannabis oil versus a sleeping pill

A 2026 trial in Thailand compared three treatments for chronic insomnia over four weeks.

Sixty adults took either a traditional Thai herbal remedy, a cannabis oil, or lorazepam, a prescription sleeping pill.

Lower scores mean better sleep. All three groups improved, with “no significant differences between groups.”

Only mild side effects were reported.

It’s an interesting result, but a small one. Sixty people split three ways is a small trial.

It also used a specific local cannabis formula, and there was no placebo group.

The catch: tolerance and withdrawal

Your body adapts

A 2016 review of sleep and substance use, in Addiction Science and Clinical Practice, explains the problem.

It found that “the sleep-promoting effect of cannabis is lessened in the chronic user”.

Meanwhile, cannabis’s negative effects on sleep intensify with chronic use.

The authors describe this as a “potential catch-22”. Heavier use may be needed to feel the sleep benefit, but that heavier use makes sleep worse overall.

Stopping can disrupt sleep for weeks

When regular users stop, sleep problems are common.

The review reports that sleep difficulties affect “anywhere from 32 % to 76 %” of people going through cannabis withdrawal.

Strange dreams typically start “1–3 days after cannabis discontinuation”, peak after two to six days and last four to 14 days. Some large studies found sleep problems lasting 43 days, and strange dreams up to 45 days.

That’s one reason people restart. They stop, sleep badly, and reach for cannabis again.

The review notes that going back to cannabis, or turning to alcohol or other sedatives to sleep, is commonly seen.

There’s an interesting twist. The Lancet Psychiatry review found that combining CBD and THC reduced withdrawal symptoms in people with cannabis use disorder.

That’s a treatment setting, though, not a sleep aid.

What sleep-lab studies show

In sleep labs, researchers track brain waves overnight. Studies of cannabis withdrawal found people took longer to fall asleep and woke more during the night.

Total sleep time and deep sleep fell. REM sleep, the dreaming stage, bounced back higher than usual, known as “REM rebound”.

The changes were more noticeable in heavy users, defined as using at least five times a week over the past three months.

The review says these disturbances build over the first two weeks. They can “persist for more than 45 days” after stopping.

What earlier research found

Effects differ between new and regular users

The 2016 review found that, in occasional users, sleep studies often showed more deep sleep and less REM sleep.

With regular use, people developed tolerance to most of these effects, including the sleep-inducing ones.

Sleep doctors’ caution on sleep apnoea

In 2018, the American Academy of Sleep Medicine said medical cannabis should not be used for obstructive sleep apnoea. It cited “unreliable delivery methods and insufficient evidence of effectiveness, tolerability, and safety.”

That statement covers sleep apnoea, not insomnia. But it shows how cautious sleep specialists remain.

How it fits together

The trial evidence suggests a modest, short-term benefit for some people. The longer-term evidence suggests the benefit fades and can reverse.

How much should you trust this?

Early. There’s a signal that cannabinoids can add some sleep time, but it rests on low-certainty evidence.

What makes it convincing

• The Lancet Psychiatry review pooled randomised trials, the strongest study design.
• Sleep gains showed up with both device tracking and sleep diaries.
• A separate review and a newer trial point in a similar direction for short-term use.

What makes me cautious

• Most outcomes in the main review had low-certainty evidence.
• Nearly half the trials had a high risk of bias.
• Products, doses and THC or CBD content vary hugely between studies.
• Most trials are short, so they can’t show what happens after months of use.
• Tolerance and withdrawal can undo the short-term gains.

What this means for you

• Try proven options first. The NHS insomnia guide covers sleep habits and CBT, which targets the thoughts and habits that keep you awake.
• Be wary of nightly use. Tolerance can build, and stopping can make sleep worse for weeks.
• If you use it, be cautious with THC. One review found THC products did no better for sleep and had more side effects.
• Check the law where you live. Cannabis rules vary widely between countries and states.
• Talk to a doctor. Especially if you take other medicines, are pregnant, or have ongoing sleep problems.

In this TED talk, sleep scientist Matt Walker explains why sleep matters so much, and what helps:

What we still don’t know

1. Which compounds help, if any? THC, CBD and CBN may act very differently.
2. What dose, and for how long? Most trials are short and use different products.
3. Does any benefit last? Long-term trials are scarce.
4. Who benefits most? Insomnia has many causes, and trials rarely separate them.
5. How does it compare with CBT? Head-to-head trials against the leading insomnia treatment are lacking.

My take: a short-term nudge, not a sleep solution

What I like about the newer research is that it takes the question seriously. There is a real signal that cannabinoids can help some people sleep a little longer.

I’m less convinced by the idea of cannabis as a nightly sleep aid. The same evidence shows tolerance building and withdrawal disrupting sleep, which is the opposite of what a sleep aid should do.

So if you can’t sleep, weed might help tonight. But for sleep that improves over months, the research points elsewhere.