Plenty of anecdotal evidence has been exchanged between fellow pot smokers describing headaches, brain fog, and general discomfort as a result of the previous night’s smoke sesh. At the same time, the many cannabis consumers who have never experienced anything like a weed hangover remain skeptical that the phenomenon even exists. The medical and scientific communities are just as ambivalent, and the lack of rigorous and contemporary research on the topic doesn’t do much to dissipate the fog. When someone says they have a weed hangover, they’re probably experiencing the following symptoms:

  • headache
  • brain fog
  • lethargy
  • nausea
  • dry eyes.

While these symptoms may be connected to overconsumption of THC, they may also be triggered by other culprits.

How to Avoid or Relieve a Weed Hangover

Whether a hangover is real or not and how or why it happens is beside the point if you wake up feeling like your head has suddenly turned into a lead helmet. Here are ways to avoid THC overconsumption and how to find some relief if you feel hungover.

  • Go Low And Slow - The best mitigation strategy is prevention. Heed the adage and “go low and slow” as you determine how much THC your body can comfortably metabolize. Start with lower doses of THC and space out the length of time between each time you consume. If you feel off—or hungover—the next day, take note and reduce either the quantity or frequency of THC consumption.
  • Avoid High THC Products - While the average flower sold at dispensaries contains 20-30 percent THC, concentrates and edibles contain much more. It is unlikely to experience adverse effects from smoking a bowl, but a high THC dab or an edible may lead to a marijuana hangover (or something like it).
  • Stay Hydrated - Life gets busy, so there’s a chance you aren’t keeping track of how many cups of water you’ve had today. Weed hangover symptoms look a lot like the symptoms of mild dehydration, so a glass of water may provide the relief you need.
  • Invigorate Yourself - If you wake up, brain steeped in fog, you’re probably going to want to go right back to sleep. Don’t. Get up, drink some water, have a cup of coffee, and go for a walk. If you’re feeling dizzy, light headed, or having trouble walking, don’t push it. Call your doctor. If you are experiencing a headache that is particularly severe and does not feel similar to headaches you have had in the past, that would also be an indication to see your doctor.

Weed Hangover, Or Something Else?

Hangover suffering man holding his aching head close up portrait with bottles of beer. Alcoholism concept. iStock / Traitov
It's possible that you're not experiencing a weed hangover. Dehydration can cause headaches and fatigue. An unbalanced diet may contribute to a myriad of health problems including inflammation, nausea, lethargy, insomnia, and headaches. There is also sleep deprivation. If you’re getting less sleep than your body needs, it’s likely that you’ll experience a combination of these symptoms.

Finally, consuming multiple substances at the same time—caffeine, alcohol, and weed for example—may lead to an unpleasant aftermath once the high has worn away. A night out with friends may include all of these triggers, so be wary of calling the next day’s migraine a marijuana hangover when it may really just be the consequences of too much junk food, too little water, and not enough sleep.

The Research Is Either Old, Inconclusive, or Absent

The most cited study supporting the existence of weed hangover effects was published in 1985. The Drug and Alcohol Dependence study examined 13 men who smoked either cannabis containing 2.9 percent THC or a placebo. The researchers found that the next morning, the men who had smoked the marijuana responded significantly differently to tests examining their emotional states and abilities to complete timed tasks. The study suggested that “marijuana smoking can produce residual (hangover effects) the day after smoking,” though it noted that “the precise nature and extent of these effects, as well as their practical implications, remain to be determined.”

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In March 1990, this Psychopharmacology study directly refuted those findings. 12 regular pot smokers participated in the study. The subjects were evaluated over two weekends. During one weekend, the participants were given a placebo. The other weekend, they were given cannabis containing 2.1 percent THC. Then, the subjects were given questionnaires and assessments evaluating their psychomotor and cognitive function. The researchers concluded that “marijuana smoking was not associated with a ‘hangover’ syndrome similar to those reported after use of alcohol or long-active sedative-hypnotics.”

marijuana joints and buds on hand iStock / sutiporn
Later that year, a small study was published in Pharmacology Biochemistry and Behavior suggesting that marijuana does cause adverse residual effects. The study examined 3 regular smokers in four 2-day sessions. Twice on the first day of each session, the subjects would smoke cannabis cigarettes containing 2.57 percent THC. Researchers would administer a series of assessments evaluating physical and mental responses throughout the first day and again on the second day to determine whether or not there were residual effects. The study concluded that “marijuana can adversely affect complex human performance up to 24 hours after smoking.”

In 1994, four years later, another Psychopharmacology study was published on the topic of alcohol and marijuana impairment the day after consumption. The study evaluated 14 women and men who either consumed alcohol alone, cannabis alone, or alcohol and cannabis in combination. The subjects were assessed on mood and performance during their most intoxicated states and then twice the following day. The study concluded that there was “little evidence that moderate doses of alcohol and marijuana, consumed either alone or in combination, produce behavioral or subjective impairment the following day.”

In addition to their small size, there are two glaring problems with existing research on marijuana hangovers, and they are relevance and potency. The evidence is over two decades old. Additionally, these studies obtained their results using cannabis with less than 3 percent THC. Most strains cultivated for retail today are packing 20-30 percent THC, and that’s just regular flower. Add concentrates to the mix, and someone could be consuming much more THC than that.

It’s likely that the body responds differently to higher concentrations of THC. In fact, overconsumption of THC has been linked to greening out, or temporarily overdosing on the psychoactive cannabinoid. The endocannabinoid receptors that THC interacts with facilitate mood, memory, pain, and appetite. While just the right quantity of THC can lead to a temporary euphoric experience, too much can cause those systems to malfunction in ways that are extremely uncomfortable.