Cannabis Science

How to Get Rid of Brain Fog From Weed

woman with brain fog from weed

You may have brain fog if you’re having trouble focusing or feeling more confused than usual. Believe it or not, brain fog is not actually a medical condition. Brain fog refers to a group of symptoms that affect your thinking. There are many reasons why you may experience brain fog. For example, brain fog is being reported as a long-term effect of COVID-19. At the same time, brain fog is being reported as a long-term side effect of consuming weed. Is there any science behind this? And if it is true, then you must be wondering how to get rid of brain fog from weed. Here’s what we know. 

Photo: Unsplash 

Does Weed Actually Cause Brain Fog?

There is a correlation between weed consumption and experiencing brain fog. 

Dr. Ahmad Chaudhry tells us, “There is some evidence that frequent or heavy marijuana use can contribute to short-term cognitive impairment, sometimes described as ‘brain fog.’”

A Harvard Health article also mentions that people who consume weed long-term may develop not only brain fog but other cognitive issues, such as difficulty with learning and attention, as well as lowered motivation. 

So, if weed can cause brain fog, naturally, you’re wondering why.

Well, Dr. Chaudhry tells us that THC is the likely culprit.

“THC disrupts the activity of cannabinoid receptors in the brain regions involved in memory, concentration, and decision-making. This can make it more difficult to form new memories, focus thoughts, and multi-task effectively, leading to the “out-of-it” feeling of brain fog. Chronic use may also alter brain structures and function related to cognition. However, research is still limited in confirming the mechanisms.”

Even though there seems to be a link between weed consumption and brain fog, more research is needed to understand the link between the two better.

Harvard Health says, “Still, future studies are needed to establish causation and explore how long-term cannabis use might impact the risk of developing dementia, since midlife cognitive impairment is associated with higher rates of dementia.”

In addition, some people say Sativa strains improve their focus and not impair it. 

Whether or not someone will experience brain fog after consuming weed depends on their biological makeup, how frequently they consume weed, and the weed’s potency. 

How Long Does Weed Brain Fog Last?

It varies.

First of all, brain fog is not just something you experience when you’re high. 

Dr.Chaudhry says, “With frequent use, these effects may linger even when not actively high. However, the degree of impairment depends on many factors like potency, dosage, and individual tolerance.”

However, to give you an idea of a timeline, Dr. Chaudhry looks at the frequency of consumption.

He tells us that for people who consume marijuana occasionally, brain fog usually resolves completely within days to 1-2 weeks from the last time they consumed weed. THC should be eliminated from the body within that time to clear the brain fog.

If you consume marijuana heavily, then you can expect your brain fog to resolve in about 2-6 weeks after abstaining from weed, according to Dr.Chaudhry. 

As a matter of fact, in some cases, the brain fog may take longer than six weeks to resolve. 

Dr. Chaudhry says most people will experience improvement in their brain fog symptoms within two weeks. 

“Most people see the biggest improvements in clarity and focus within the first 1-2 weeks. Persistent symptoms could indicate an underlying condition, so see a medical provider if fogginess lasts over a month after quitting marijuana.”

How to Get Rid of Weed Brain Fog

There are several ways you can get rid of weed brain fog. Dr.Chaudhry says that the following activities should get rid of weed brain fog: 

  • Abstaining from weed
  • Sleep
  • Hydration 
  • Supplements
  • Doing mentally stimulating activities

If you’ve tried this suggestion and you’re still experiencing brain fog, Dr Chaudhry recommends seeing a doctor to rule out other causes like an underlying health condition.

Abstaining from Weed

Brain fog usually resolves when you stop consuming weed. Therefore, if weed is really the cause of your brain fog, abstaining may be enough. 

Dr. Chaudhry says opting out of consuming weed for several weeks allows THC to clear the system and reverse tolerance effects.

If you’re interested in abstaining from weed, prepare to experience withdrawal symptoms such as:

  • Insomnia
  • Irritability
  • Decreased appetite
  • Weight loss
  • Weird dreams 

Don’t worry; these symptoms will likely resolve within a week. However, certain symptoms, such as irritability, may last up to a month. 

You can opt for over-the-counter solutions to alleviate your symptoms in the meantime, though. 

For example, some chamomile tea may help you fall asleep more soundly. 


Sleeping is a great way to get rid of brain fog from weed. 

Maybe you haven’t abstained, or you’re still experiencing brain fog anyway. 

Dr.Chaudhry says getting plenty of restful sleep can help get rid of the brain fog from weed. 

WebMD says you should aim for 7-9 hours and avoid caffeine and alcohol before bed or even after lunch. 

WebMD also recommends keeping your phone and computer out of your bedroom. 

Finally, they recommend going to bed and waking up at the same time every day. Yes, that includes the weekend, too. 

You’re probably wondering about the link between sleep and brain fog.

One of the reasons why you may be experiencing brain fog is your lack of restful sleep. 

Healthline says, “The most common effect of too little sleep is sleepiness, of course, but also moodiness and brain “fog” — the general inability to think straight or remember anything.”

They also mentioned a 2017 study showing that lack of sleep interferes with your brain cells’ ability to communicate. The communication issues between your brain cells cause “temporary mental lapses that affect memory and visual perception.”

The result? Brain fog symptoms. 


You’re probably tired of being told to ‘drink more water,’ so we’ll just say, ‘Increase your hydration.’

Our bodies are mostly water, and that includes our brains.

According to a BBC article, “Losing just 2 percent of the water in your body (mild dehydration), can impair your cognitive performance, attentiveness, short-term memory and may affect decision-making ability. These symptoms, which affect your ability to think, are often collectively described as “brain fog”, a non-medical, colloquial term.”

Healthline says dehydration can lead to brain fog symptoms, so drink up to alleviate them.

“Dehydration contributes to fatigue, so drink more water than you usually would. The additional liquid intake will also cause more frequent trips to the restroom. But getting up and making the short trip to relieve yourself can help with alertness.”

Even though there is no evidence that weed causes dehydration, it’s worth keeping hydrated; it could help alleviate the brain fog. 


You may want to consider starting supplements to get rid of your brain fog from weed or otherwise. 

Dr. Chaudhry says, “Consider supplements like omega-3s and antioxidants that support brain health.”

Wondering what other supplements could be helpful?

Rocky Mountain IV Medics recommend the following for brain health:

  • Vitamin C
  • Vitamin B complex, including B12
  • Vitamin D
  • Ginseng
  • Soy lecithin
  • Magnesium
  • L-theanine

Ensure you speak with your doctor before starting any medication, including supplements. 

If you’re someone who consumes weed in any capacity, you may want to see the doctor anyway to see if you’re lacking in any vitamins. 

Unfortunately, weed consumption could cause a deficiency in certain vitamins. A 2019 study says, “However, foods ingested by Cannabis users are nutritionally deficient due to underline malabsorption. In addition, Cannabis-induced vomiting can further cause malnutrition.”

Doing Mentally Stimulating Activities

If you’re ready to get rid of brain fog from weed or otherwise, do mentally stimulating activities. 

Dr.Chaudhry says mentally stimulating activities can sharpen your cognition. 

According to Healthline, you can try the following brain games and activities:

  • Crossword puzzles
  • Scrabble
  • Soduku
  • Painting
  • Photography
  • Learning how to play an instrument
  • Creative writing
  • Rubik’s cube
  • Chess
  • Jigsaw Puzzles 


So, if you are wondering how to get rid of brain fog from weed, the first step is abstaining from weed. You can try other things to get rid of brain fog, such as getting more sleep, drinking more water, taking supplements, and doing activities stimulating your brain. It’s not fully understood how weed causes brain fog, but it may involve THC’s effect on the brain. We’re looking forward to more research.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].