How Long Does Marijuana Stay in Your System [Fully Explained]

It’s something you’ve probably thought about to a great degree; how to get drugs out of your system, and how to do it fast. I mean, we all love the effects of weed, but what about the consequences of tomorrow? Or the next day? Or next week? Random drug testing is common at many workplaces in the US. And it goes without saying that the difference between passing and failing can have major repercussions.

In truth, the actual effects of cannabis tend to fade quickly (a matter of hours). However, marijuana can be detected in your body for weeks after you’ve consumed it. Sometimes even longer. The length of time that weed can be detected in your system depends on several factors, including:

  • Age
  • Gender
  • Metabolism
  • Body Mass Index (BMI)
  • How often you smoke

The amount of time THC remains detectable in cells depends on several factors, including things like diet, BMI, and general activity levels.

Understanding cannabis’ interaction with the human body

Whether you are new to smoking weed and curious as to how long it will stay in your system, or if you are afraid of potential drug screening at work, understanding how weed interacts with the body – and knowing how to clean out your system based on how long it is detected for in various parts of the body – is invaluable information. Being safe from random drug testing is the never-ending goal for thousands of cannabis users. This article is designed to help.

For everyone out there wondering “how long does pot stay in your system” or “how to clean out your system fast,” hopefully this guide will help set your mind at ease. Passing an all-important drug test can be a pivotal moment in your life, and we’re here to help.

How Long Does THC Stay in Your System

Tetrahydrocannabinol, aka THC, is the ingredient in marijuana responsible for the plant’s psychoactive effects. In other words, it’s the compound that causes the high. When addressing the question of how long it takes weed to leave your system, THC is what we look at. In a loosely scientific sense, we want to know how long THC metabolites “linger around” fatty tissue for.

how long does thc stay in your system

When smoking marijuana, THC enters your system almost immediately. However, if ingested (eaten as an edible) the process is a little longer – at least 20 minutes. Whichever option you choose, the result will be the same. Your body will quickly metabolize the psychoactive compounds; this is why we stay high for hours instead of weeks at a time.

THC Leaves the Blood Relatively Quickly

Because THC is broken down relatively rapidly and modified into molecules known as metabolites, it is detectable in the blood for the shortest amount of time. This is, of course, good news for those of you who will be undergoing a hematology screening, or for those who are wondering how to how to clean your system in one day.

When the liver breaks down THC, it forms at least 80 different metabolites – one of which is THC-COOH. This is the metabolite that is primarily screened in drug tests. The question of how long THC stays in your system is a complex one with a variety of contributing factors. Naturally, this can make figuring out how long cannabis stays in your system a difficult task.

how long does thc stay in your system

Results May Vary!

Truth be told, the amount of time THC stays in the system varies from person to person. To add to the confusion, there are also thousands of different strains of marijuana available on the market, and each one has different cannabinoid profiles and varying levels of THC.

In terms of its chemistry, THC is lipid-soluble. This means the molecule will embed itself into the body’s fat tissue. As a result, THC and its metabolites are stored more readily in people with higher body fat compared to people who are lean. To put it kind of crudely, the fatter you are the longer weed will linger in your system.

This is unfortunate for those with impending drug tests because THC is eliminated the slowest when it is stored in fat tissue. It may be present for days, weeks, or even months depending on how much weed was consumed. The difference between occasional users and frequent users can also be vast. Frequent users will retain THC metabolites in their fat tissues for a lot longer than occasional users. So if you’re a habitual user and are frantically scouring the web for how to clean your system fast, there may not be a whole lot you can do.

How Long Does It Take THC-COOH to Leave the Body?

On average, THC-COOH will take about four days to exit the body. In a study done a few years ago on 52 test subjects, it was found that an average of 4.9 days was required for THC to be entirely cleared from the system. However, it took up to 18 days for THC-COOH (the trace metabolite) to be eliminated from some of the test subject’s urine samples.

In a separate study, it was found that THC stayed in the system of infrequent users for 48 to 72 hours, while detectable amounts were seen anywhere from 9 to 12 days after THC exposure in more frequent users.

How Long Does Weed Stay in Your Urine?

If you’re asking yourself ‘how long does marijuana stay in your system,’ what you’re more likely wanting to know is the amount of time that it stays in your urine. In other words, when people ask things like ‘how to flush your system efficiently,’ what they really want to know is how to clean urine to the point where THC metabolites can no longer be detected.

Drug testing is of course pretty standard protocol among companies all over the world. Most employers require that their employees undergo a test revealing the absence of drugs. Of course, you already know this. After all, you’re here online searching for how long weed stays in your system for!

how long does it take for weed to leave your system

Apart from blood and saliva tests, urine testing is one of the most effective ways to screen a person for marijuana use. This is quite obviously why one of the most frequently-searched terms online is ‘how to clean your urine.’ Urine testing is the cheapest method of drug testing, and it has one of the longest detection periods. Therefore, it’s essential you know how long weed can be detected in your urine after consuming it.

THC-COOH vs. THC: What’s the Difference?

Most drug tests that are used to detect the presence of marijuana and its metabolites, including urine testing, will test for the presence of THC-COOH rather than THC. As we explained above, THC-COOH is a metabolite that forms when the liver breaks down the active THC compound. If this metabolite is present in urine, it means the body has recently processed THC.

How long THC shows up in your urine will vary depending on how often you consume marijuana. The more marijuana you use, the longer it will be detectable (apologies if that insulted your intelligence). Ultimately, the frequency of use will determine the method(s) you choose for how to clean your system from drugs.

Here’s a general guide for how long cannabis can stay in your urine:

  • For a single use (i.e. once in a 30 day period): up to 8 days
  • For regular use (i.e. 4-6 times over a 30 day period): up to 15 days
  • For frequent use (i.e. 10-15 times over a 30 day period): up to 30 days
  • For heavy use (: i.e. 20+ times in a 30 day period): up to 45-77 days

As you can see, the above figures are not exactly “excellent” news for all you stoners out there that are wondering how to clean your system of drugs in one day.

How to Pass a Urine Test

how to pass a urine test

Based on the above information, you may be reasonably worried if you are a regular or heavy marijuana smoker and have to take a drug test soon. One to three months is a long time, and you may need a little help to pass a urine test. Unfortunately, there is no foolproof way of beating the system with zero traces of THC in your urine. The good news is there are products and methods out there that might be able to help you (such as the following from Toxin Rid).


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Detox drinks and detox pills are also available to be purchased and are a relatively decent solution for how to clean your system. For the specific purpose of cleaning your urine to eliminate drug traces (i.e. detectable THC metabolites), you can try drinking excessive amounts of water to dilute your urine, but this is rarely effective. Also, bear in mind that if your urine is too diluted, you run the risk of voiding your drug screening.

Fruit Pectin for Urine Drug Tests

One of the more commonly used methods to pass a urine test (a favorite among the most desperate consumers) is the fruit pectin method. Fruit pectin is a starch that is derived from the cell walls of produce. It is often found in jams and preserves. The fruit pectin is mixed with an electrolyte drink (like Gatorade), and then consumed at least two hours prior to a urine test (possibly a day or two before as well).

After drinking the Gatorade/pectin mixture, you should then follow up with a bottle or two of water and some B vitamins. The theory behind the fruit pectin method is that because it is a naturally occurring fiber, it makes THC exit the body through the bowels and not the urine, as it usually would.

Detox methods do not work 100% of the time. Their effectiveness will largely depend on the amount of weed you consume on a daily basis.

Nothing Is a Guarantee…

While the above methods have the potential to help you pass your urine test, none of them are guaranteed to be 100% effective. Even if you follow all the directions to a T, you may still ultimately fail your test.

Moreover, some detoxes could even make you sick given the presence of compounds that your body might not be used to. If you are aware of an upcoming drug test and are concerned about your job, your best bet would be to slow down on your marijuana consumption (as hard as that might be), rather than rely on one of the above tricks.

Want to learn more about passing a urine test? Check out the best ways to pass weed urine and blood screens.

How Long Does It Take for Marijuana to Get Out of Your System?

Finally, we get to the actual question of ‘how long does it take for marijuana to leave your system.’ Previous research has shown that the amount of time marijuana remains in the body is affected by three key factors:

  • How much a person smokes.
  • How often they smoke.
  • For how long they have been smoking.

For most people, marijuana will stay in the body in “detectable quantities” between 10 days and a month. But as we’ve mentioned, the length of time can (and will) vary drastically. Individuals considered to be “regular smokers” have had drug tests that produce a positive result up to 45 days after their last use. Likewise, heavy smokers have reported positive tests up to 90 days after full abstinence.

how long does it take for marijuana to get out of your system?

Here are a few factors that could affect how long it takes marijuana to leave your system:

  • Body Fat Content – The chemical compounds that are responsible for the effects of weed on the brain is stored in fat cells. Thus, the higher your percentage of body fat, the longer cannabis will be present in your system.
  • Metabolism – The metabolism of an individual will affect the rate at which their body can eliminate cannabis. It will also affect their body fat content, which further influences cannabinoid detection.
  • Drug Strength – Different cannabis strains have different levels of strengths; the stronger the strain, the higher the concentration of THC. This could result in more cannabinoids being left in your body, which may take longer to eliminate.

How Long Does THC Stay in Your Saliva?

For anyone asking the question ‘how long does weed stay in your saliva,’ you’ll need to first determine how long the THC has been present.

how long does thc stay in your saliva

Typically speaking, THC is detectable for the least amount of time in saliva. This is of course great news for anyone undergoing drug testing via the means of, well, testing the saliva. (Coincidentally, this is also a popular method used by traffic police to test drivers for possible “drug-driving” offenses).

THC metabolites can be detected in saliva for about an hour after smoking, and can remain in your saliva for up to 24 hours. This is true even for just a single smoking session. For regular smokers, the number could be more like 72 hours. Heavy smokers are advised to wait at least a week before taking a saliva test, as THC has been known to accumulate in salivary glands over time.

Knowing how long THC stays in your saliva is important. Check out our guide: How Long Does Weed Stay in Your Saliva?

How Long Does Weed Stay in Your Hair?

Hair is often a big concern when it comes to the length of time weed is present in your system. It is actually believed cannabis has the longest detection window in hair. In fact, the hair drug test was developed to identify long-term users rather than one-time or infrequent users. Standard hair tests will typically look for drugs in the system over the last 90 days.

how long does weed stay in your hair?

Drugs, in general, are one thing, but what about the question ‘how long does marijuana stay in your hair? Generally speaking, cannabis metabolites can be detected in the hair for up to seven days after the consumption of pot. Just like other weed test methods, though, hair follicle tests look for the presence of the THC byproduct known as THC-COOH, rather than THC itself.

Also, it’s interesting to note that first time users and infrequent users of weed are much less likely to test positive for weed by a hair follicle test, as it takes a decent amount of consumption for cannabis metabolites to reach hair follicle tissue.

Wondering ‘how long does marijuana stay in your hair?’ Looking for solid tips to pass your next hair test? Read our updated THC and Hair Guide

How Long Does Weed Stay in Your Blood?

Just like every other question we’ve answered, in order to determine how long weed stays in the blood for we need to look at the THC element and its metabolites. Blood testing for cannabis use is actually not a very common method, but it’s still important to understand for those who know they’ll have to undergo this particular screening.

how long does weed stay in your blood

The good news is that cannabinoids prefer nice, fatty parts of the body to reside in rather than the bloodstream. In other words, THC and its metabolites don’t stay in the blood for very long. First time or infrequent users can expect THC to show up in the blood for up to 24 hours after consuming weed. In more frequent users, it could show up for three days. For “regular” users, it’s recommended they wait for up to a week before taking a blood test.

All in all, there shouldn’t be too much worry surrounding the use of cannabis if you need to undergo a blood test. As we mentioned, blood tests for cannabis use are not very common. As long as you’ve had enough time beforehand to “prepare” for the screening, you should be OK.

Final Thoughts on How Long Weed Stays in the System

While this article has given insight and guidelines that have hopefully answered most of your questions regarding how long weed stays in your system, it is difficult to give an exact answer. As we have seen, there are a number of factors that can affect the outcome – the most obvious of which is the frequency of use.

If you are a newbie or a “now-and-then” kind of consumer, you should have minimal concern since the length of time that weed will stay in your system is a lot lower. Here is a quick general recap of everything we’ve covered in the form of a table:

how long weed stays in the system

We know that the type of drug test you undergo will have a major impact on whether or not you test positive. For example, a urine test will show weed in your system for a longer period of time than a blood test. If you are seriously concerned (and/or the thought of drug testing makes you anxious), your best bet is to hold off on consumption. Or at the very least, minimize your weed intake for the time being. After all, it’s impossible to know exactly how long weed will show up in your system.

And lastly, it’s important to note that this article has been composed only as a GENERAL GUIDELINE. It is by no means 100% “scientifically” accurate, and certainly is not a guarantee that you’ll pass a drug test — even if you follow one of the above recommendations. Keep in mind that everyone’s biochemistry is different, and thus outcomes will differ from person to person.


Check out some of the best-rated products of this year for helping to pass a drug test.

Want to know how long THC can stay in your system? Try out our THC Drug Test Calculator:

Review by Daniel J Isaacman, M.D.

Another very comprehensive review from the people at WayofLeaf. This article helps the reader understand how drug testing is performed, the difference between tests involving saliva, blood and urine, and the various factors that affect how long a given test can test positive following usage. A few key take-home summary points for the reader:

1)There is great variability between the length of time a given test will remain positive. One should never assume that the “short end” of the given time period will be adequate.

2) Frequent users will tend to stay positive for longer periods of time than occasional users. This is due to “build up” and storage of THC metabolites within the body.

3) The greater the fat content of one’s body, the greater the potential for THC and its major metabolite THC-COO to hang around.

If one expects to be drug tested for an important reason in the near future, the best bet is to refrain for several weeks to months before the given testing. The longer, the better, in my opinion. One must remember that the repercussions of a positive drug test can be quite damaging.


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