How Long Does Marijuana Stay in Your System?


Are you a pot smoker thinking about applying for a new job and worrying about the potential employer taking drug tests? The first thing is first. Cannabis is legal in many jurisdictions, as many places offer medical marijuana for those who suffer from various ailments. Therefore, you do not have to worry when your potential employer orders you to take a drug test. However, if you happen to live in an area where cannabis is not legal, you have a good reason to have some concerns. That is when you have a good reason to worry about how long the cannabis can last in your system. Let’s go over that because there is not a one-size-fits-all approach to this answer.

The Detection Time Depends On The Cannabis Dose

Marijuana is detectable in your system from one to 30 days, and that means if you were to take a blood, saliva, or urine test, it would show up. Sometimes cannabis is detectable in your hair for a few months. So the timeframe is long-range, and that all depends on how much pot you smoke or consume. Therefore, higher doses of the pot will stay in your system for much longer than low doses.

For instance, if you only spent one night taking hits from a bong and did not smoke or consume pot again, then it would be detectable for a day or so. However, if you have been smoking cannabis or ingesting it daily, you can accurately guess that the marijuana would be in your system for much longer. Therefore, you can pretty much realize that the weed will stay in your system for more than three months in that case.

That means, if you are worried about the marijuana being detectable in your system, then you will want to stop smoking or ingesting it. But, even then, some by-products of weed may be detectable in your system for a while. That is because the drug tests can also find and measure the derivatives of cannabis even though the cannabis itself may no longer be in your system.

The Type Of Test Performed Can Yield Different Results

What type of drug test will you undergo? Will it be urine, blood, saliva, or hair? If your potential employer wants to book a urine test which is the most common method for testing, you will find that the weed does not stay in your system for very long if you are an occasional user by using it up to three times a week. Therefore, the pot will only be detectable in urine for three days. If you smoke or ingest cannabis four times a week, you can expect to have the drug detected in your urine for five to seven days. If you use it daily, it will remain in your urine for about ten to 15 days. If you smoke several times a day, expect it to be in your urine for over a month.

If you have a blood test to detect pot in your system, the weed is less detectable as it can only stay in your blood for about one to two days. However, if you are a chronic user, you can expect the pot to be in your blood over 25 days. If you smoke weed, then it becomes detectable in your bloodstream within seconds after inhaling it. If there is a reason to believe you recently smoked weed, then a blood test is the test of choice if you need testing for whatever reason.

Saliva tests are less standard than urine or blood tests, and officers will only use them for roadside testing in areas where pot is legal. If you smoke or ingest pot occasionally, traces are detectable in your saliva for one to three days. However, if you use it often, it can be detectable in your saliva for close to a month.

Finally, let’s go over hair testing, which potential employers want to use if they need to know if you smoked or ingested pot months ago. That is because, after inhalation or ingestion, pot reaches the hair follicles through the small blood vessels. That is how tiny amounts can stay in the hair.

Your hair grows one-half of an inch per month, and the tester will remove a one-and-a-half-inch piece of hair from the scalp to examine it. If you used cannabis within three months or longer, then the tester will detect weed this way. Now that you know how long cannabis stays in your system when testing let’s talk more about the metabolization.

How Long Does Marijuana Take To Metabolize In Your System?

As you know, the main ingredient of pot is THC or delta-9-tetrahydrocannabinol and that is the stuff that you want because it gives you the high that you love. Once you either inhale or ingest THC, it goes directly to your bloodstream. Sometimes THC is stored in your fat and organs temporarily. Once it goes through the kidneys, your bloodstream can reabsorb THC. Your liver breaks down your THC and it consists of more than 80 metabolites. However, there are only a few that drug testers want to detect because they remain in your body longer than THC itself. Eventually, they pass through your waste.

There are many factors that play a role in how long the THC stays in your system which include your BMI, age, gender, and how your body processes it. The more potent the weed, the longer the THC will stay. However, there is nothing you can do to rush it out of your system.

Recent research provides additional insights into this topic:

  1. Heavy Users and Drug Tests: A study found that heavy marijuana users could still fail drug tests weeks after abstaining. This study highlights the unpredictability of THC metabolism and its detection times, which can exceed two weeks for regular users.
  2. THC in Breath Samples: A study conducted by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder analyzed THC levels in the breath of regular cannabis users. The study found that THC levels were similar before and after use, making it difficult to determine if someone had recently used marijuana based on breath THC concentration. This research is significant as it explores the possibility of developing a breathalyzer for cannabis.
  3. Future Research: The NIST study is part of ongoing research to develop a reliable cannabis breathalyzer. The next phase will involve more participants and breath samples, aiming to produce statistically significant results. This research underscores the complexity of accurately detecting recent cannabis use.


If you are worried about testing positive for THC because you are looking for a job shortly, you will want to know several things. Firstly, if you live in a jurisdiction where marijuana‘ is legal, in most situations, your potential employer would not do a drug test for cannabis and would test for other drugs. However, if you live somewhere it is not legal, then you will need to know the timeline of how long pot stays in your system. That way, you can make changes between now and when you plan on going for your interview. It is not a one-size-fits-all approach.