why does weed make you sleepy

Why Does Smoking Cannabis Make You Feel Tired?

Several studies could point towards a more complex link between cannabis and the feeling of tiredness experienced after smoking.

Every regular cannabis smoker has experienced drowsiness, lethargy, or a general lack of motivation after or while smoking weed. Many will shrug this off as the nature of a specific strain, while some may find these attributes desirable—especially if insomnia is an issue. Newly published research may point to excessive cannabis consumption as a cause of long-term feelings of drowsiness or laziness. For those choosing to use recreational cannabis to avoid the hangover or comedown of other drugs, this strategy may prove somewhat ineffective.


A strong indica strain will undoubtedly knock you down onto the sofa, where, let’s be honest, not a lot gets done. For a vast majority, this is a desirable trait, and the reason users choose indica strains to begin with. If you enjoy smoking cannabis and live an otherwise active lifestyle, then smoking will not suddenly make you lazy or lethargic for the long-haul. The answer to why marijuana makes us feel drowsy and in turn, less motivated, could actually come down to the way THC is absorbed and subsequently interacts with the neurotransmitter dopamine.


Published by The National Institute For Biotechnology Information, the following research points to an apparent reduction in dopamine levels as a result of excessive cannabis use. In summary, the study found that heavy smokers of cannabis, those who were borderline dependent, produced significantly less dopamine than that of non-smokers or light users.

Using a sample group of 19 frequent cannabis smokers and 19 non-smokers, this study stands out because, although similar tests have been undertaken before, none have included active smokers. Importantly, the frequent cannabis smokers had all admitted to suffering from psychotic-like symptoms when smoking, a sign of excessive use.

Michael Bloomfield, PhD stated that “After a period of time, your brain cells aren’t able to make as much tyrosine hydroxylase, an important enzyme that’s a key component in making dopamine”.

This stunting of chemical processes is a result of the way the cannabinoid THC interacts with our body’s natural endocannabinoid system.


With heavy THC consumption seemingly impacting dopamine levels, what does the release of dopamine mean to our bodies? Dopamine acts as a regulator for effort threshold—how much effort is required to complete a task and what the rewards are. Those with higher levels of dopamine are more likely to undertake functions that require energy. Dopamine also plays a role in giving us that “rewarding” feeling when taking part in pleasurable activities like sex, eating, and exercise. If the level of dopamine released during these activities is reduced, then it stands to reason that motivation to perform would also decrease.


Cannabis is a complex organism. Alongside key cannabinoids THC, CBD, and CBN, cannabis contains terpenes. These molecules provide the vast array of aromas we have come to love. More than that though, theorists suggest that terpenes work in unison with cannabinoids to boost or enhance the relative effect.

A 2011 study examined the impact of the terpene myrcene. Myrcene is known for giving cannabis a musky, mango-like aroma. Furthermore, myrcene was found to induce a hypnotic effect, as well as display muscle-relaxant properties. Combined with THC, these two compounds work in conjunction to make individuals feel tired. Previous studies have found similar attributes with the terpene linalool, although this time, linalool partnered with CBD to produce a drowsy effect.


Playing a potential role in reducing dopamine levels, what else can smokers expect THC to impact? Well, the answer may reside in the land of Nod. Anecdotal evidence from users would suggest we sleep better after smoking cannabis. Many have reported that we sleep so much better that the feeling of drowsiness can be hard to shake the morning after. With so many swearing by cannabis as a sleep aid, what scientific research is there to support this thesis?

Two studies, the first conducted in 1975 and more recently in 2004, delivered relatively inconclusive results. Both noted a decrease in REM sleep (rapid eye movement sleep phase), but our deep sleep phase remained roughly the same. It could be surmised that a reduction in REM sleep could result in the feeling of increased tiredness experienced the morning after smoking cannabis.

Both investigations have something in common—the vast number of variables yet to be explored. The results are still too inconclusive to draw a satisfactory conclusion. Instead, further studies will be needed, in which sample size, age of participants, strains smoked, and any previous medical issues, etc are taken into account. One thing is for sure; there does seem to be some correlation between smoking cannabis and the feeling of tiredness. The exact cause of this phenomenon is still unknown.


What does that mean for us? Well, for now, the usual rules apply. Enjoy cannabis as you usually would, while being aware that every user will experience symptoms differently. If you do find yourself having periods of drowsiness or lethargy the morning after smoking cannabis, then a few simple steps can be taken to counteract this.

These include selecting a strain with less THC, smoking less, and hydrating. And of course, exercise, a healthy diet, and good ole coffee can help shake the fatigue as well; be it a result of smoking weed or not.

Numerous users will have experienced drowsiness when smoking cannabis. Is this a natural reaction, or is there a long-term impact on our bodies?

Does Marijuana Help You Sleep?

A recent study concludes that marijuana use might actually disrupt your sleep. However, experts point out there may be other factors involved.

Marijuana may make you sleepy, but does it really help you sleep?

With the increasing frequency of marijuana legalization and its medical use throughout the United States, many are turning to the drug to treat insomnia and sleep disorders.

However, a study from the University of Michigan concluded that depending on how frequently an individual uses marijuana, it may not help them sleep at all.

It may actually worsen their sleep quality.

The study recruited 98 subjects who were divided into three groups: daily marijuana users, non-daily marijuana users, and a non-user control group.

Individuals were disqualified from the study for a variety of reasons that could affect sleep.

Illicit drug users and binge drinkers couldn’t participate, nor could individuals working night shift jobs, or those using sleeping medications.

Researchers found that that the daily-use group had higher levels of insomnia (almost 40 percent) compared to non-daily users (10 percent) and the control group (20 percent).

“These results are consistent with previous studies showing an association between sleep disturbance and heavy marijuana use in adults,” the researchers wrote.

The significance of their report is that it suggests that while marijuana may help some individuals in the short term or through intermittent use, continual use makes insomnia worse.

“The effects of marijuana on sleep in intermittent users may be similar, in part, to those of alcohol where improvements in sleep… have been reported with intermittent use, whereas daily use results in the worsening of sleep,” they wrote.

Another facet that Deirdre Conroy, PhD, a clinical associate professor in the University of Michigan Department of Psychiatry and lead author on the study, touches on in a separate publication is what happens when daily users stop using marijuana.

Their sleep worsens during a withdrawal period if they attempt to quit using the drug or use it less frequently.

The study was limited in that quantity of use wasn’t measured.

All daily users were considered to be “heavy” marijuana users, but researchers admit they were, “unable to know if the sleep reports of daily users were a result of frequency of use or quantity of use.”

They say that future studies should recruit individuals who only smoke minimally to observe how quantity could potentially affect sleep quality.

Medical marijuana is also used to treat a variety of ailments from anxiety to PTSD.

Those ailments almost certainly play a role in sleep disorders.

Researchers discovered that when they controlled the study for anxiety and depression, the difference in reported insomnia levels disappeared.

“This raises questions about how marijuana is affecting people with and without anxiety and depression,” Conroy, who is board certified in sleep disorder medicine, told Healthline.

“We don’t know if our participants started using [marijuana] to treat anxiety and developed insomnia or if they used [marijuana] to treat insomnia and developed anxiety,” she explained. “Additional studies looking more specifically at these relationships will help us better understand this relationship.”

The study further complicates the medical literature on the relationship between marijuana and sleep — which is already inconsistent.

“To date, controlled clinical data with regard to the impact of cannabinoids on sleep is limited and somewhat mixed,” Paul Armentano, the deputy director of the National Organization for Reform of Marijuana Laws (NORML), told Healthline.

He points out a 2017 review on the subject matter as evidence of that.

“Cannabis is frequently used by patients as a sleep aid and they typically report subjective benefits from cannabis with regard to getting to sleep and staying asleep,” Armentano said.

One of the problems in making a conclusive assessment is that marijuana contains numerous different chemicals that affect the body’s endocannabinoid system.

The two most prominent, tetrahydrocannabinol (THC) and cannabidiol (CBD), both exist in varying amounts, depending on the strain of marijuana.

Therefore, there’s the potential for different strains to affect sleep differently.

The review that Armentano brought up suggests that CBD may be helpful for insomnia, but THC may impair sleep quality in the long run.

Marijuana is also known to decrease REM sleep — the stage closely related with dreaming.

A separate study concluded that the “sleepy” effects of THC seem to lessen as a user’s tolerance grows.

Another study, a newer one from 2017 , found that marijuana users who decreased usage over time had improvements in anxiety, depression, and sleep quality.

In short, considering the many variables involved — including mental health issues, marijuana strain and potency, and quantity of use — a definitive answer on the relationship between marijuana and sleep remains somewhat elusive.

However, Conroy’s research may be helpful in sorting out some of the details of who are better candidates for using medical marijuana for sleep disorders.

“If you have depression, cannabis may help you sleep. But if you don’t, cannabis may hurt,” she writes.

The research also points to future work investigating a potential optimal dosing strategy.

That is, if smoking heavily every day is too much, how would less frequent, smaller doses affect sleep quality?

A recent study concludes that marijuana use might actually disrupt your sleep. However, experts point out there may be other factors involved.