Quick answer: A weed hangover is the dull, foggy feeling some people report the morning after cannabis. Controlled studies have looked for it since the 1980s and found little. A 2023 review of 20 studies found no next day effect in about 61 percent of tests. Dose, sleep and daily use explain more than THC does.
What is a weed hangover, at a glance?
A weed hangover is a next day feeling of fog, tiredness or a heavy head that some people report after using cannabis. There is no clinical definition of it. Researchers use two other terms instead.
The older term is the hangover effect. The newer one is residual effects, or next day effects. Either way, the evidence base is small, old and mixed.
Most of the confusion comes from lumping three separate things together. They have different causes and different timelines.
| What people mean | When it shows up | What is actually driving it |
|---|---|---|
| Genuine next day residual effect | 8 to 24 hours after use | THC, in theory. Barely detected in controlled tests. |
| Dry mouth, a short night, a late meal | The morning after | Behavior around the session, not the THC itself |
| Withdrawal in a daily user | 1 to 3 days after stopping or cutting back | A pattern of heavy use, not last night |
Is there any real research on a weed hangover?
Yes, but there is not much of it, and the findings do not agree. Four studies carry most of the weight.
L. D. Chait at the University of Chicago ran the cleanest one. Writing in Psychopharmacology in 1990, he gave 12 regular smokers 40 standard puffs across five evening sessions. One weekend used 2.1 percent THC, the other a placebo. The next mornings he tested mood, sleep ratings, and psychomotor and cognitive tasks. He found no evidence of residual intoxication.
Chait and J. L. Perry repeated the idea in 1994, also in Psychopharmacology. Fourteen adults took alcohol, marijuana, both or neither. Next day evidence was weak again.
The outlier is older. Yesavage and colleagues at Stanford reported in the American Journal of Psychiatry in 1985 on ten licensed private pilots. Each smoked a cigarette with 19 mg of THC. Twenty four hours later they flew a simulator landing task. Performance trended worse on every measure, with real deficits on several aileron, elevator and landing scores. The pilots did not think they were impaired.
Then there is the review that ties it together. Danielle McCartney, Anastasia Suraev and Iain McGregor of the University of Sydney published "The 'Next Day' Effects of Cannabis Use: A Systematic Review" in Cannabis and Cannabinoid Research in 2023. They pooled 20 studies, 458 people and 345 performance tests.
In 209 of 345 tests, THC had no next day effect. Twelve tests showed impairment, and all five of those studies lacked a randomized, double blind, placebo controlled design. Another 121 tests gave too little information to judge. Three suggested improvement.
So the honest state of play is thin. The samples are small and mostly male. Much of the work predates modern product strength. Nobody has run the large, well designed study this deserves.
How does a weed hangover compare with an alcohol hangover?
The two are not close, and the alcohol side is far better documented. The alcohol column below comes from a 2016 Utrecht University survey in Current Drug Abuse Reviews, by van Schrojenstein Lantman, van de Loo, Mackus and Verster. It recorded which symptoms drinkers name.
| Symptom | After alcohol | After cannabis |
|---|---|---|
| Nausea | Named by 23.1 percent of drinkers | Not a documented next day finding |
| Headache | Named by 22.8 percent | Commonly self reported, not confirmed in tests |
| Tiredness | Named by 9.6 percent | The most common self report of the three |
| Vomiting | Named by 5.2 percent | Not reported in the next day literature |
| Thirst | Named by 3.9 percent | Dry mouth is an acute effect, usually gone by morning |
| Concentration problems | Named by 2.9 percent | Self reported, weakly supported |
| Measured task impairment | Well documented | None in 61 percent of 345 tests |
| Reported duration | Up to about 24 hours in that review | Usually clears within hours of waking |
Am I hung over or just still high?
Most mornings, you are still high.
McCartney and the same Sydney group reviewed 80 papers and 1,534 performance outcomes in Neuroscience and Biobehavioral Reviews in 2021. Lower inhaled doses impaired simple tasks for about four hours. Higher inhaled doses stretched to six or seven hours on complex tasks such as driving. High oral doses ran up to ten hours.
A 50 mg gummy at 10pm is not finished at 8am. Our guide to whether edibles expire covers dose and labels in more detail.
Washington takes this seriously. Under RCW 46.61.502, subsection 1(b), a driver is guilty of DUI with a blood THC concentration of 5.00 or higher within two hours of driving. There is no roadside breath test for it.
Do dehydration and poor sleep explain most of it?
They probably explain a good chunk, though the sleep evidence is weaker than people assume.
Dry mouth is real. A 2022 paper in Scientific Reports titled "Cannabinoid CB1 receptors regulate salivation" points at CB1 receptors in the salivary glands. It is a session effect, not a morning one.
Sleep is messier. Velzeboer and colleagues published "Cannabis and sleep architecture: a systematic review and meta-analysis" in Sleep Medicine Reviews in 2025. They pooled nine of 18 studies. Cannabis did not consistently change sleep length, latency, wake time, efficiency or staging.
The old claim that THC flattens REM sleep came from small, high dose trials. Newer work at lower doses often found no REM suppression.
What the same review did find consistently was the reverse. Withdrawal from active use was tied to shorter total sleep, longer time to fall asleep and REM rebound.
There is also the boring explanation. A late night, a late meal, a few drinks and a 6am alarm will produce a rough morning with no cannabis involved at all.
Could it be withdrawal rather than a hangover?
If you use every day, withdrawal is the more likely answer. The numbers here are much stronger than the hangover numbers.
Anees Bahji and colleagues at the University of Calgary pooled 47 studies and 23,518 people for JAMA Network Open in 2020. Cannabis withdrawal syndrome ran at about 47 percent among regular or dependent users, with a confidence interval of 41 to 52 percent. It was 17 percent in population samples, 54 percent in outpatient samples and 87 percent in inpatient samples. Daily use was linked to higher rates.
Ofir Livne, Dvora Shmulewitz, Shaul Lev-Ran and Deborah Hasin at Columbia University looked at what it feels like. Their 2018 paper in Drug and Alcohol Dependence found the syndrome in 12.1 percent of frequent users. The pattern was clear.
| Withdrawal symptom | Share of affected frequent users |
|---|---|
| Nervousness or anxiety | 76.3 percent |
| Irritability, anger or aggression | 71.9 percent |
| Any physical symptom | 70.4 percent |
| Sleep difficulty | 68.2 percent |
| Low mood | 58.9 percent |
| Headache | 47.9 percent |
The timing separates them. A hangover follows one session. Withdrawal follows stopping or cutting back, and it runs for days, not a morning.
Which weed hangover myths need correcting?
Four come up at our counters every week.
"Indica gives you a hangover, sativa does not." No controlled study has tested that. The labels are also poor guides to chemistry, which is why we wrote about what sativa and indica labels really tell you.
"Terpenes cause it." Nobody has measured that either. What terpenes actually do is a smaller claim than the internet makes.
"It is just dehydration, so water sorts it." The dehydration story has never been tested against a placebo for next day symptoms.
"Stronger product, worse morning." Dose and route matter more than product type. A big oral dose outlasts a strong puff. Our note on reading weed measurements covers how to think in milligrams.
Some people should skip cannabis the night before entirely. That means anyone driving early, flying, running machinery, sitting an exam or on call. It also means first timers, who have no baseline to judge against.
How do people cut the odds of a rough morning?
Mostly by choosing a smaller dose and stopping earlier in the evening. None of this is medical advice, and none of it is a fix.
Know your milligrams. Washington labels must show serving size, servings per package and total THC under WAC 314-55-105, subsection 3(f).
Respect the lag on anything you swallow. State rules put the warning "Caution: Intoxicating effects may be delayed by 2+ hours" on edible labels. Anyone taking a careful approach to RSO dosing knows this already.
Watch the mixers. Alcohol plus cannabis produced the greatest impairment in that 1994 Chait and Perry study. Both together beat either alone.
Pick a format you can measure. A metered device is easier to track than a shared joint, which is part of the case for and against disposable vapes.
Keep a note for a week. Write down dose, time, product, and how you felt at 8am.
Frequently asked questions
How long does a weed hangover last?
Most people who report one say it clears within a few hours of waking. There is no agreed clinical duration, because the condition is not well defined in research. What is measured is acute impairment. McCartney and colleagues at the University of Sydney reported on that in 2021. Lower inhaled doses impaired people for about four hours. Higher inhaled doses ran six to seven hours on complex tasks. High oral doses ran up to ten hours.
Can edibles cause a worse morning than smoking?
They can run later, which is the main difference. The 2021 University of Sydney review found that high oral doses can impair performance for up to ten hours, against about four to seven hours for inhaled doses. Take 50 mg at 10pm and the clock is still running at breakfast. That is not a hangover. That is the dose still working.
Does drinking water stop a weed hangover?
No study has tested that, so nobody can say. Dry mouth is a real acute effect of cannabis and it is uncomfortable. It is also usually gone by morning. The dehydration story is popular because it is simple, but it has never been measured against a placebo for next day symptoms. We are not going to claim water does something it has not been shown to do.
Is a weed hangover a sign of withdrawal?
It can be, if you use every day. Bahji and colleagues pooled 47 studies and 23,518 people for JAMA Network Open in 2020 and put cannabis withdrawal syndrome at about 47 percent among regular or dependent users. Daily use was linked to higher rates. The tell is timing. A hangover follows one session. Withdrawal follows stopping or cutting back, and it lasts days.
Can you fail a Washington DUI test the morning after?
It is possible, and the rule is strict. Under RCW 46.61.502, subsection 1(b), a driver is guilty of DUI with a blood THC concentration of 5.00 or higher within two hours of driving. Blood THC drops quickly after inhaling, but oral doses and daily use both change that picture. The simple answer is not to drive while you still feel anything at all.
Does CBD prevent a weed hangover?
There is no evidence for that. No published trial has tested CBD against a placebo for next day effects after THC. Shops repeat the idea because it sounds plausible. Ask us what a product contains and we will read the label with you. Ask us whether CBD stops a rough morning and the honest answer is that nobody knows.
Where can we help you work this out in person?
Bring the pack in. Our Cannabis Guides will read the milligrams with you and talk through timing.
You can browse the West Seattle edibles menu or the Redmond edibles menu before you come. Hours and parking are on the West Seattle store page and the Redmond store page.
In a wet Puget Sound February, a foggy morning is not always the gummy. Still, we would rather talk you into a 5 mg dose than sell you a 50 mg one you regret.
Origins Cannabis is a licensed Washington retailer serving adults 21 and over in Redmond and West Seattle. Nothing here is medical advice. If you are using cannabis for a health reason, talk to a healthcare provider who knows your history.