How Long does Marijuana Stay in Your System?

Once you smoke marijuana and get high it takes a few hours to several months to eliminate its compound from your body.

Even once the effects are worn off. 

However, the time duration to eliminate cannabis compounds (mainly THC) depends upon many varying factors, which we are going to discuss today.

Also, you will get to know that the main cannabis compound, THC, which is responsible for making people high, takes a different amount of time to leave your different parts of the body.

Such as the time duration for detection of THC in your blood is different from the saliva. The same goes for hairs, urine, and even your whole system. 

Though it also depends upon the frequency and way of consumption as well.

How long does marijuana stay in your system


Why THC or delta-9-tetrahydrocannabinol is only important?

When we talk about marijuana then we are mainly talking about the main component of it – THC or delta-9-tetrahydrocannabinol. 

Because in cannabis mainly this compound is responsible for the euphoric effects

And, the second reason is drug tests mainly check for THC and its metabolites in the body. 

While the different medical researches are also based on this chemical compound and its effects on our body. These researches have also revealed that how weed is metabolized in our system and when it completely leaves, which we will be covering within a few minutes.

So, now, it is clear that why THC is an important term in cannabis and your system.

How weed affects our body?

Well, irrespective of the way you consume weed, the main effect it produces is euphoria

Though before we head on how long does marijuana stay in your system, it is essential to know how it affects our body when consumed differently. 

One of the popular ways of consuming marijuana is smoking or inhaling. As cannabis is smoked or inhaled, THC gets into the bloodstream through the lungs after the heart pumps out in the whole system. 

As THC enters the body it initiates its effects of euphoria by affecting the endocannabinoid system and brain. While the central nervous system and other organs are also affected. 

After that, THC gets metabolized in the liver, stored as fat in the system. However, the drug testing mainly looks for one metabolite of THC which is known as 11-nor-9-carboxy-THC or THC-COOH. It is an inactive form of THC which stays in the system for a longer time than the active THC and gradually leaves the body through urine and feces.

That is why these drug testing can easily detect the THC compound even after several days of consumption. 

Apart from this, when cannabis is consumed orally then chances are high that in saliva it can make the drug test positive. Unlike inhaling, THC enters the bloodstream through the intestine. Then it affects the heart and brain to show its effects further. 

Though a larger amount of THC gets metabolized in the stomach still its metabolites remain in the system. 

How long does marijuana stay in urine?

In drug testing across different regions, urine is one of the most preferred ways. 

According to the SAMHSA or Substance Abuse and Mental Health Services Administration, the most common cut-off concentration of THC-COOH to be founded in urine is 50ng/mL, though it might vary depending upon the frequency of consuming marijuana. 

Although a review in 2005 published by National Drug Court Institutes suggested that THC concentration in urine rarely lasts for 30 days to be detected by screening. 

Taking the SAMHSA’s recommend cut-off concentration (50ng/mL), THC concentration in the urine of a chronic marijuana user can be founded within 10 days or more from the last smoking time. 

Although this duration decreases in the one-time or occasional smokers. 

If we decrease the cut-off THC concentration at 20ng/mL then the duration of detecting THC in the urine of a chronic smoker could be found up to 21 days after the last consumption. However, at the same cut-off range, drug screening might not be able to detect THC in the urine of a one-time smoker after seven days of last consumption. 

Apart from this, according to Mayo Clinic Proceedings detection of THC in urine can be founded within these days: 

  1. For heavy users (who consume multiple times a day): more than 30 days
  2. Daily users: up to 15 days
  3. Moderate users (up to four times a week): up to 7 days 
  4. Occasional users: up to 3 days

How long does marijuana stay in blood?

After inhaling marijuana, it takes seconds to catch THC in your bloodstream. However, after the last usage of cannabis, THC can be detected in the plasma even up to several hours. 

In a 2009’s report in the journal Addiction, an experiment was done by the researchers on 25 frequent cannabis users to monitor the cannabinoid concentration in their blood. 

And, after the seven days of preventing cannabis use, researchers founded that nine of the samples didn’t show any THC concentration while in other samples, THC was still there in their system within the same period of preventing cannabis. 

Therefore, doesn’t matter if the active form of THC can not be founded in the bloodstream after a certain time but the other THC form can still be found in the system even after several weeks. 

Though this duration might vary depending upon usage and frequency of marijuana as well.

Apart from this, according to another study in 2004 published in Therapeutic Drug Monitoring, plasma concentration of THC peaks just in three to eight minutes. While it also decreases with a half-life in about 30 minutes.

This study also claimed that THC can be found in the blood for up to five hours while the THC-COOH can be detected even up to 25 days.

Hence, different studies have shown a certain time of up to one month for the detection of THC form in the bloodstream. Though depending upon the usage and frequency it can completely vary and last longer as well for detection in drug screening. 

How long does marijuana stay in hair?

According to the National Institutes of Health, hair follicle tests can detect marijuana compounds even up to three months. This is because, after the consumption of marijuana, its compound reaches into the hair follicle through small blood vessels, and hence, it can be detected there for a longer period. 

In contrast, according to the research published in Scientific Reports, detection of marijuana compounds in hair follicles is not expected to be accurate.

The report suggested that it is because there are high chances that THC or its metabolites can be transferred to hair follicles from a smoker or regular user of marijuana to a non-user or non-smoker through exhaled smoke, sweat, or even with hands. 

Supporting this theory, we can take an example like if a weed smoker exhales the smoke near someone who doesn’t smoke then there are possibilities that THC can be transferred to his/her body hair or head. 

Although this same study founded that after giving 50 milligrams of THCA to the participants in an experiment for up to one month every day, no THC was there in the hair samples. While the inactive form of THC i.e., THC-COOH can still be detected. 

And, the catch is, this same study also concluded that sometimes the detection period of THC in hair samples can go for even up to 90 days, which is the same as the report of NIH. 

One of the recent studies in 2017, published in Drug and Alcohol review did an experiment with 136 hair samples and founded that THC can be detected in 77% of heavy or chronic users. 

While the detection of THC decreases in the people who use cannabis lightly (39%) and is completely nil in non-users. 

So, ultimately, it was concluded that with increased frequency of cannabis use, THC can be founded in hair samples easily. Although the authors of the study also acknowledged that it’s not a reliable method to detect light cannabis usage. 

How long does marijuana stay in saliva?

If marijuana is consumed orally, then its components can be found in the saliva for up to 29 days according to a 2014 study published in Drug Testing and Analysis. Though the consumption and frequency of marijuana usage again affect the detection period in the following manner:

  1. Occasional users: 1 to 3 days
  2. Chronic users: 1 to 29 days

Detection of THC compound in saliva happens when weed is consumed via smoking or through edibles. 

How long does marijuana stay in your system?

Marijuana’s compounds are found in blood, saliva, hair, and urine within a different timeframe. However, when it comes to the time frame of how long does marijuana stays in the body or system then, unfortunately, there’s no clear evidence or data on it. Because it depends upon many other factors. 

Still, with the help of existing researches and data on marijuana existence in different body parts, you can estimate the time that in within how much time marijuana can leave the body completely. 

Key factors affecting the time duration of marijuana presence in the system

As said before, there is no clear or exact data that can give you a timeframe that after this, marijuana compounds could not be found in the system. 

However, you can be aware of the factors that affect or influence how long weed stays in your system to use it positively to eliminate marijuana from the system. 

Frequency of marijuana usage

As mentioned multiple times, the frequency of marijuana usage is one of the main factors that affect how long does marijuana stays in your system. One-time users or occasional users are still okay but the chronic or heavy users are on the dangerous side from the drug detection as well as from eliminating from the system side as well. 

Also, in long term, frequent use of cannabis can lead to multiple health issues including cannabis withdrawal symptoms. 


Apart from frequency, the dosage of cannabis is also a crucial factor. The larger the dose will be the more time it will take to leave your body. Even the more time your body will need to completely metabolize it. 


People with high metabolic functions are on the positive side. This means the higher metabolic functions help to break down cannabinoids or THC at a faster rate than the people with slow metabolic functions in their system. Hence, the faster THC breaks down, the faster it leaves the system and reduces the chances of getting detected in drug screening tests. 


We have mentioned before that THC-COOH is fat-soluble and therefore, people with having fat in their system can accumulate this THC metabolite for a longer time. Though they can break it down with the help of regular exercise. Regular physical activity will help to burn the fat and hence the THC will be released into the blood and further, it can be eliminated by the urine or feces. 


Dehydration can cause an increase in the levels of THC in the body. That is why it is recommended that stay hydrated and drink a lot of water to reduce the chances of drug detection. Although it might not affect the test significantly dehydration can cause. So, it is better to drink water and stay hydrated. 

Frequently asked questions

#1. How to metabolize weed faster in your system?

First of all, you have to expect that once the weed you consume through either of ways, your body needs some time to deal with it and metabolize it. However, regular physical activity, exercise, a healthy diet, and staying hydrated can help to some extent but don’t expect a drastic change. 

#2. Are weed detox remedies good enough?

The kits available in online or offline markets are not a reliable option. Some of the kits prefer to drink more water to dilute into the urine and then further intake of supplements such as vitamin B-12 or creatinine to mask it, which is not a completely trustworthy way to do it. 

#3. How long does it take to feel the effects of weed?

After smoking or inhaling, you can experience the effects of weed within 15 to 30 minutes. Although if ingested then it can take one hour or two to make you feel the highness

How Long does Marijuana Stay in Your System: Conclusion

Finally, now you know that marijuana might stay in your system from one day to several months from the last usage depending upon various factors. Also, you have now the idea that by which factors you can reduce the timeframe for eliminating marijuana from your system. 

About 420 Evergreen
I am Jack Pattinson. I am into weed dispensary business for 10years+. Started my journey as bud tender, and now I own a dispensary in North Bonneville, Washington, USA.

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