How Long Does Marijuana Stay In Your System (and How to Get it Out Faster)

One of the most common questions from people who even occasionally smoke marijuana ask before taking a drug test is how long does THC stay in your system?

These days it’s very common to be asked to submit to a drug screening before your employment is accepted with a company.  Even if you have been in your position for many years, due to changing regulations, you may all of the sudden be asked to submit to a random drug test by your employer.  Perhaps you’ve been preparing for a new job or are expecting a drug test to take place, and you just want to be sure that you’re in the clear.

Unfortunately, there is no easy answer to that question at this time.  That’s because of the unique nature of THC (tetrahydrocannabinol), which is the active chemical in marijuana that gives users that “high” feeling.  THC is the psychoactive element in marijuana and is fat-soluble, rather than water-soluble like most other drugs that will leave your system within days.  If THC were water-soluble, all traces of marijuana would be out of your system within a week regardless of how much you used.

Since THC is stored in your body’s fat cells, marijuana will remain in the body for some time after you have smoked or ingested the substance.  If marijuana is ingested, rather than smoked, it will take a little longer to be absorbed into the blood, which can be up to an hour and a half.  On each occasion that you smoke or consume marijuana you saturate your blood with the active ingredients, and the chemicals in your blood are then absorbed by the fat cells. Because of the way it is stored, THC takes longer to fully clear the body than any other common drug.

Once the THC is stored in your fat cells, it is secreted slowly over time through urine or sweat. While stored in the body’s fat cells, tests can trace the drug through blood, urine and hair follicle exams. Although there’s no exact length of time that can be applied to how long marijuana will stay in your system, you can determine a general timeframe by examining several factors.

How Long Will Marijuana Last in Your Urine

The most common way to test for THC is in the urine because it is the cheapest method and has a long detection period. However, the length of time will vary depending on the frequency of use because of the cumulative effect of THC.

  • For somehow who has just smoked for the first time, or at least the first time in more than 90 days, THC can remain positive in your urine for up to 8 days depending on how much you smoked in that instance. Even if you only took a few puffs, enough trace amounts of the drug can remain in your system to be picked up by a urine test.
  • If you are a frequent smoker, meaning even as little as one smoking session every few days, then THC can easily last in your system for up to 15 days. Since THC is stored in your fat cells and is slowly excreted from your system, each time you smoke it adds more of the active ingredient to your body.  So even if you’re only smoking a few times week, the THC in your body is increasing, allowing urine tests to detect it even after several weeks of not smoking.
  • A heavy smoker, which would be someone who smokes on a daily basis consistently, or even missing a few days here and there, can have THC last in their system for up to 30 days. Constant intake of marijuana means that THC is always increasing in your fat cells, even as THC from weeks ago is being drained, you are replacing the substance faster than it’s being released.  This is bad news for regular pot users, as if you’re planning to get a new job that may require a drug screening you’ll have to be sure to give yourself at least a month to clear any THC from your urine.
  • Finally, some long term heavy marijuana smokers have been tested positive for THC from anywhere between 45 and 90 days after their last use. That’s as much as 3 months that THC could still be detectable in your system, even after you stop smoking.  These are obviously the outlying scenarios, but with the decriminalization of marijuana in many states it is now easier than ever for people to become heavy smokers.

Although you can’t measure the time it takes for marijuana to get out of your system down to the exact day, you can get a general idea of the timeframe it will take depending on how much and how frequently you smoke.  It’s a good idea to plan ahead if you’re expecting a drug test to come up at your job, or are expecting to get a new job requiring a test.  Remember, even just one puff could significantly delay the amount of time it takes to get clean, and it’s also a good idea to stay away from second hand marijuana smoke until you pass your drug test.

Generally, the less marijuana you smoke, or the less often you smoke it, the quicker it will leave your body.  Research has shown that people who are steady users of medical or recreational marijuana will clear the drug from their systems differently than less frequent users.  Those who smoke marijuana on a daily basis, or very heavily, will release THC more slowly over a longer period of time than someone who only smokes it randomly or not at very high level.  A single use of marijuana is more likely to be cleared from the user’s system within a few days.

For regular smokers, however, it can take an average of 14 to 30 days for all traces of detectable marijuana to leave their system, although in some cases of very heavy use for long periods of time it can be longer.  Long-term users may still have cannabis in their body two to three months after they last smoked it.

How Long Marijuana Says in Your Blood

The primary chemical in marijuana, THC, is absorbed in the body rapidly when smoked.  How long the chemical stays in your bloodstream will depend on how deeply the user inhales the smoke, how long they hold the smoke in their lungs and the length of the puff taken.  A typically smoker will absorb anywhere between 5 and 30 milligrams of THC after smoking an average joint.  Concentration of THC peaks very quickly in your bloodstream, within 3 to 8 minutes, and will decrease just as quickly, while having a half-life of around 30 minutes.

For this reason, THC is hardly ever measured in the blood because the metabolite of THC doesn´t bind to the blood for very long. As a result, testing cannabis in the blood only detects recent use and is most likely to be used if you were in a car accident and suspected of driving while under the influence of drugs or alcohol.

Length of Time Marijuana Stays in Your Hair

Over recent years hair based drug tests have become more prevalent due to their ability to detect a variety of different substances for a longer period of time after someone’s last use.  Hair is very different from blood or saliva when being utilized for drug testing because it provides a much longer window of substance detection.  Depending on the hair’s characteristics, such as pigment and length, THC can remain detectable for as long as 12 months.

It should be noted, however, drug testing of the hair cannot determine when the user last smoked marijuana, just that they had at a certain point in time.  Concentrated amounts of THC and other drugs in pigmented hair have been found to be 10 times higher than those of non-pigmented hair, since they bind with THC for longer periods of time.  THC can be found in hair follicles for up to 7 days after a single use.  The downside is that studies have shown false positives can be caused by using hair to test for marijuana, since secondhand pot smoke can actually be absorbed by the hair for a period of time.

How Long Marijuana Stays in Your Saliva

Saliva drug tests are used for an instant, on the spot results and are easier to transport and deploy randomly than a lot of traditional drug tests.  Saliva tests for marijuana are not typically used, since THC is only detectable in it for up to 24 hours after smoking a single joint.  This type of drug testing is still utilized for “spot checks” or surprise testing of employees who have not had time to prepare or anticipate the test.

Saliva can be taken from the mouth for testing very quickly and is difficult to fake.  Even if a user has time to prepare for the saliva test and rinses out their mouth thoroughly beforehand, the rinsing effect will only last for about 2 or 3 minutes before your saliva reaches an equilibrium again and will contain THC.

Some law enforcement agencies across the country have started to employ saliva drug tests for drivers who they suspect of being under the influence of marijuana.  THC has a very short lifespan in the saliva, but this type of test can catch people who have smoked it recently and then gotten behind the wheel of a vehicle.

Factors Affecting How Long Marijuana Stays in Your System

One of the reasons why it can be so hard to pin down how long marijuana will last in your system is because it can depend on so many different factors.  Since THC is stored in the user’s body fat, the speed in which it leaves the system can fluctuant.  Here are the most common factors that will determine how long marijuana stays in your system and can be detected by urine tests.

  • Body Weight
  • Body Fat Index
  • How Much is Smoked
  • How Often It’s Smoked
  • Metabolism Rate
  • Potency of the Marijuana

Ways to Increase the Speed of Marijuana Leaving Your System

Because of how long marijuana stays in your system and how it can adversely impact a user’s life or employment, people are always seeking for ways to get it out of their systems faster.  Although there are many different suggestions available, each with its own degree of effectiveness, here are the most popular ways to try and accelerate the process of getting THC out of your system.

Flushing out your system

The number one recommended way of speeding up the process of eliminating THC from the body is by drinking a ton of fluids, mainly water.  You can start by having a gallon jug full of water at your disposal at all times and basically drinking as much as you can as frequently as you can.  This is still a slow process, but has been shown to help as well as diluting the THC concentrated in your urine.

Vitamin B or B-12

If you’re trying to pass a urine test by drinking tons of water beforehand, therefore diluting your urine enough to make the THC undetectable, you’ll need to make sure that it actually has some color to it.  Taking vitamins B or B-12 several hours before your test is recommended.


Recent studies have shown that since THC is stored in fat cells, and when you work out rigorously you start burning fat, the THC is actually released by steady exercising.  This can also produce a “high” effect on your body even if you haven’t smoked marijuana for some time, as long as it’s still stored in your fat cells, the THC will be released into your bloodstream and can give you a buzz.  Besides the effects of feeling high again, this will help release the THC into your blood stream and then will be flushed out in your urine faster.

Now that you know more about how long marijuana will last in your system, you can better prepare for future or random drug tests that may come your way.  Even if you live in a state where recreational or medical use of marijuana is legal, an employer can still fire or choose not to hire you because of THC being present in your system.  Be sure to plan as far ahead as possible, for there is no easy way to get the THC out of your system quickly, it will always take a certain period of time to leave naturally.


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