Most of the time, the effects should be long gone after about eight hours.
There’s no disagreement about what it’s like to wake up after a night that involved tequila shots at last call and maybe a few double dry-hopped IPAs too many. The pounding headache, dry mouth, and cartwheeling stomach are universal signs that you overdid it—and that you’re spending the morning squinting at your phone with one eye open and texting “never drinking again” to your group chat.
Booze hangovers are so well documented in clinical studies that there are actual best practices for how researchers should study them. But when it comes to the consequences of overdoing it on weed, there’s far less agreement. While some people swear that they are worse for the wear the morning after they get high, many other people balk at the notion that a so-called “weed hangover” exists. It doesn’t help that some of the most widely cited studies on marijuana’s morning-after effects were conducted nearly three decades ago.
In one—very small—study from 1990, for instance, 16 people were recruited to either smoke a joint, or if they were less fortunate, puff on a placebo containing no THC at all. Then they went to bed. (Sounds like our kind of study.) The following morning, the researchers gave the subjects a bunch of tests to see if their mental or physical abilities were in any way dulled.
For the most part, the subjects who’d smoked weed the night before seemed to be just fine: “No evidence of residual subjective intoxication was found, and most of the behavioral tasks and mood scales were unaffected the morning after,” the authors concluded, adding that “marijuana smoking was not associated with a ‘hangover’ syndrome similar to those reported after use of alcohol or long-acting sedative-hypnotics.”
What those researchers could not have anticipated, however, is the nuclear-grade ganja that your average recreational drug user in 2018 now packs. In the 1990 study, for instance, the strength of the joint participants smoked was around 2.3 percent THC—on par with the average at the time. By 2003, however, that average strength had more than doubled to 6.4 percent. Today, some strains being sold in Colorado are well above 20—and in some cases, even 30—percent THC.
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We know what the implications here would be if we were talking about alcohol, rather than weed: A five-percent (ABV) beer won’t give the average person much of a buzz. Drink the entire six-pack at once, however, and that same person will likely wake up with a crushing headache—and possibly a vague memory of singing “Danny Boy” in the back of a Lyft.
Unlike with alcohol, however, increasing the potency of THC doesn’t necessarily appear to hinder your body’s ability to recover from it. “In our medicinal cannabis studies, it has not been a common complaint to experience side effects from the previous day or evening of dosing,” says Barth Wilsey, an associate physician who works with the University of California’s Center for Medicinal Cannabis research.
But while there’s not much evidence for the existence of a weed hangover, withdrawal symptoms—which are sometimes conflated with hangovers, but aren’t quite the same thing—can still affect longtime users who quit cold turkey. “Over time, they accumulate THC and its metabolites in their body,” Wilsey says. “Stopping the cannabis acutely might lead to symptoms of withdrawal.” Wilsey believes that’s what some people might actually be describing when they complain of a weed “hangover.”
Common cannabis withdrawal symptoms share some things in common with what you might experience after a rough night out—anxiety, restlessness, irritability, and sleep deprivation, for starters. The symptoms usually begin the day after someone stops using after a prolonged period of time. The symptoms peak between two and six days, and can persist for up to two weeks, Wilsey says. To prevent withdrawal, slowly tapering off your cannabis use is the way to go. Gabapentin, a prescription medication, can help ease symptoms if tapering isn't an option.
But if you’re not a daily user, and you’ve smoked an average dose—roughly a one gram joint—the majority of cannabis’s effects should be long gone within eight hours of use, regardless of its potency, says Mitch Earleywine, a professor of psychology at the State University of New York at Albany and author of Understanding Marijuana. Earleywine also points out that most anecdotal reports of “weed hangovers” often fail to account for the simultaneous use of alcohol, caffeine, nicotine, and antihistamines, or the fact that a big night often means more running around and less sleep.
Even if weed is to blame for your sluggishness, Earleywine suggests a couple of easy time-tested remedies. “Plenty of fluids and an extra dash of caffeine,” he says, “will likely undo what little effect there is.”
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