How Long Does Weed Stay In Your System: Urine, Saliva, Hair & Blood


Wondering how long does marijuana stays in your system? Every time you consume it, weed stays in the system for a specified period, whether you’re a chronic user or you’ve just smoked it once. Knowing how long THC metabolites remain present in your body can be helpful, especially if you’re going to have an upcoming drug test. Weed tends to be very detectable and remains so far longer than most drugs.
In this article, we’ll have an in-depth look at how cannabis drug residues remain in the urine, saliva, hair, and blood, as these are the four primary samples taken for drug testing. Urinary and saliva testings are two of the most frequent methods used, while hair and blood tests are less common.
So how long does it take to get weed out of your system for a drug test? With the body left to its own devices, this is the same as answering how long THC lasts in your body, but with active detox efforts using products or/and home-made remedies, weed might be undetectable much sooner.

Detection Windows

How Long Can Marijuana Stay in Your Body?

Below is a marijuana detection time chart that can help you determine how long weed remains detectable in your system.

How Long Can Weed Stay in Your Bloodstream

 A heavy user taking a saliva test, for instance, may find that THC toxins are non-present if the drug test takes place after a week of no weed consumption. However, it could continue to remain in the individual’s urine for 29 days or more. The time it takes for THC to be entirely out of your system for each of the four main drug testing methods depends on a range of factors, such as your body fat levels and how your system processes drugs. Because of the difference between individuals regarding these factors, it may be essential to take estimates with a grain of salt. The National Drug Court Institute’s researchers are critical of the idea that THC stays in urine after 30 days which is why they consider any positive urine test as a sign of drug use within the last month. Still, at least theoretically, marijuana could just be hiding out in fat cells, and they can come bursting out after a month due to intense fat burning or weight reduction.
In a scientific article published by the organization, it is stated in a 1984 study from Johansson and Haldin that *even though potential factors restricting interpretation (the study subjects) with exceptionally long cannabinoid detection times (over 30 days) were just that—exceptional.” So, in practice, they found very few people for whom marijuana was detectable after 30 days.

Table 1

Drug Test Type
THC Detection Windows For Various Types of Tests*
One time/Infrequent user Regular User Heavy User
Urine 72 hours 10-15 days 30+ days^
Bloodstream 72 hours 7-10 days 10-21 days
Saliva 1-3 days 1-29 days 1-29+days
Hair 90+ days 90+ days 90+day

*These are estimates taken from a variety of reliable sources and they apply to the average person. However, for some individuals, the duration that THC remains in the urine may vary, staying for a longer or shorter period than average. It’s possible that one joint lasts in your system for as little as a day or less if you are not a regular smoker.

As mentioned, this 30+ day estimate could be overestimated although it is a common reference in the marijuana literature.

THC Metabolization

THC, also known as delta-9-tetrahydrocannabinol, is the psychoactive ingredient in weed. It is one of the substances testers will look out for when testing for marijuana’s presence in a drug test sample. Testers may also search for its psychoactive metabolites as THC is metabolized or broken down in the liver. THC contains over 80 metabolites, some of which can be stored in fatty tissues and organs before being re-emitted into the user’s bloodstream. Of the metabolites that result from the breaking down of THC, TCCOOH and 11-OH-THC are the most important of the lot. Metabolites such as 11-OH-THC, which remains psychoactive even after being transformed from delta-9-THC or just THC in the liver, are inevitably turned into COOH-THC, a non-psychoactive metabolite. The non-psychoactive metabolites will eventually be excreted from your body through the urine. These are scientifically proven and backed by contemporary research (Sharma, P., Murthy, P., Srinivas Bharath, M. M.).

Types of Drug Tests

As discussed above, drug tests are conducted through urinary, hair, saliva, and blood samples. Each test uses various procedures to search for drug residues, with some methods being used in multiple test types, such as immunoassay-based testing.

Summary of Tests

  • Urinalysis: EMIT + confirmation test
  • Hair Follicle Test: ELISA + GC/MS test
  • Saliva Test: ELISA + LC/MS/MS
  • Blood Test: Immunoassay test

Urine Test

A urinary drug test is usually conducted via enzyme multiplied immunoassay technique (EMIT), one of the most common drug tests. Testing is sometimes done on the spot, without follow-up confirmation tests. This approach involves taking a urine sample and testing it to check for increased activity in the enzyme mixed with the samples. An increase in enzyme activity marks the presence of the drug or its metabolites. The test picks up on THC metabolites when they are present, making cannabis detectable in urine. If the testing is considered essential, testers could make a second test procedure if the first one resulted in a positive to confirm if the result is accurate. More complex and costly forms of urine tests also exist but if you have a urine test, it’s more than likely going to be a regular EMIT testing. The duration you will have to wait for weed substances to leave your urine also depends on the specific test you will take. The less expensive the testing method, the less time it requires for you to wait for weed to not show up in your pee. More inexpensive tests may also fail to detect dilution. Most employers will utilize regular on-the-spot urine testing without confirming results. Whether negative or positive, testers may not guarantee your result for accuracy. If you test positive after a reasonable period of abstinence, it’s always a good idea to ask for a confirmation test to ensure an accurate result.

Hair Follicle Test

Hair follicle tests are not standard drug testing methods, but they’re one of the most effective methods for testing. They can detect THC in a person for longer durations than other forms of testing, as weed will show up on hair follicle drug tests even if consumed three months prior. Such screenings involve taking a tiny hair sample from close to an individual’s scalp. The sample piece is then sent to a lab for analysis and testing. Hair tests, just like urinalysis, have two stages to achieve the highest degree of accuracy possible. Firstly, an enzyme-linked immunosorbent assay or ELISA test, a rapid method to detect drug residues, is conducted. An ELISA test involves antibodies being placed on a plastic layer. If drugs are present, they will interact with antibodies in a variety of specific ways. If the ELISA stage tests positive, a GC-MS or gas chromatography-mass spectrometry test will then be used to confirm the initial outcome. A GC-MS test detects drug toxins by separating substances from one another in a single sample. It will then allow testers to analyze the nature of each substance and search for signs of drugs or drug metabolites. Generally, testing more than 1.5 inches of hair is not a legal practice such that marijuana is detectable in your hair follicles for a prolonged period greater than 90 days, but technically, you could test older hair and discover drug use as long as a year ago.

Saliva Test

Saliva or mouth swab tests involve analyzing a sample of saliva for drug residues. Saliva drug test detection times are not especially long but these tests are usually the second most common drug testing method after urinary tests, if not the most common depending on the region and/or sector. First, a swab is taken from your saliva glands and this is then collected to be a sample for analysis by the testers. An ELISA test is usually initially used by testers to screen for drug use from a saliva sample. Then a test known as an LC/MS/MS test is used to verify any positive results that emerge from phase one of this drug screening approach. The first step of this phase ‘liquid chromatography’ will separate substances within the sample so that they can be analyzed by a mass spectrometer which will look for any drug toxins present in the various sample components. Cheaper, on the spot testers may not avail themselves of confirmatory tests, so if you are sure you have a false positive, you should quickly ask for confirmation tests.

Blood Test

Blood testing, like hair follicle tests, is quite rare when it comes to drug testing. Weed stays in your blood system for less time and at lower concentrations which makes it even less common considering that it is more invasive than a saliva test. When a blood screening is conducted, it tends to require immunoassay testing for testers to look for drugs like marijuana in the bloodstream. Before the testing happens, your blood sample will be taken as it would for a regular blood test. The sample is either tested at the same facility sent off in a separate lab for analysis.

Possible Ways to Detox

Natural body detox/quitting weed for a period leading up your test

To be certain that your body is naturally detoxed, you need to abstain from smoking weed for about 30 days. For other drugs, it will take less time to get them out of your system.

 3 days for LSD, to 30 days for cannabis. Amphetamines only hang around for about 3 days, so sometime authorities will demand random testing so that you don’t just abstain when you know a drug test is coming.

Detox drinks

Detox drinks will work by a method known as dilution. You will be asked to drink several ounces of water and given a drink containing b-vitamins, diuretics, creatine, and electrolytes. The b-vitamins will make your urine yellow despite it being dilute which would normally make it clear, a dead giveaway that one is trying to dilute the urine. Creatine will replace the creatinine which would otherwise come up as dilute. Electrolytes will prevent water intoxication from drinking too much water which can be dangerous. Any good detox drinks just have to contain the ingredients listed above and should contain no ingredients which can cause an overdose. Mega Clean and other detox drinks by Detoxify are solid detox drinks at reasonable prices.

To detox, the hair, the Macujo, and Jerry G Methods are used. The Jerry G Method is safer in our opinion and merely requires bleaching and dyeing the hair twice over a 10 day period. Most of us have used hair dye before so that’s no big deal. The hair dye should contain ammonia, and you should dye your hair your natural hair color because if the hair looks treated, they may go in for an armpit or groin hair.

To detox orally for a saliva test, brush the inside of your mouth well, then use peroxide mouth wash. Peroxide can oxidize drug residues.

Detoxing the blood may be difficult to do safely, but it needs a dilution regimen. Luckily blood drug tests are rare and also unreliable.

Detox pills

Detox pills contain the same ingredients as detox drinks for the most part. The difference is it’s in pill form and you will be ordered to drink several bottles of water in order to carry out a dilution regiment. One particular exception is Toxin Rid. This detox pill does not contain typical ingredients. It is used to help in thoroughly flushing the system rather than just to produce dilute urine.

 Home-Made Detoxifiers

You can always detox at home with b-vitamins, water, electrolytes (salt and baking soda), and creatine. Many people have these at home already, or you can buy them separately and it will run you cheaper than buying a detox drink. The warning you need to heed at home is that it is not safe to just drink gallons and gallons of water trying to detox yourself. You can get electrolyte imbalances and water intoxication. This will cause swelling of the brain and can result in death. This has happened to people who took water and milk drinking challenges. The body can only handle so much water. So, don’t drink an uncomfortable amount of water trying to detox yourself as this does not work. Weed hides well in fat cells, not in the bloodstream and you can’t force it out quicker with drinking an excessive amount of water. You can only dilute it, or you can try burning fat so that it comes out quicker. If you try burning fat with exercise, you need to stop for a couple of days before doing the test. If the cells are still leaking THC, much of it will end up in your urine. You have to burn the THC out, then prevent fat burn just before going through your test, then you will get only a light trickle of THC into the blood, into the urine, and with a little dilution, you may test negative.


It’s your body and what you do on your own time is no one’s business so being sure that your drug test produces negative results is a matter of protecting your body from unreasonable search and seizure as defined in the Constitution of the United States of America. The most efficient way to clean up your system for a urine drug test or any drug test for that matter is to simply stop taking drugs for a significant period of time leading up to the test. Detox products are available on the market however and many marijuana users turn to such products or home remedies to beat a drug test. If you consider this approach, ensure that it is legal to do so in your particular territory first. Defrauding the government of the United States is considered a federal crime so keep that in mind should you decide to use a detox method in an effort to pass a federally administered drug test.


“How Long Will THC Stay In Your System?” Quora, Quora, 2018,
“Drug Court Practitioner Fact Sheet” Paul L., Cary M.S., 2020,
“Human Metabolism of THC” Rupp, Marlene, Sapiensoup Blog, 2016,
“What Is Tetrahydrocannabinol (THC)?” Medigrowth, Medigrowth, 2020,

This article about Medical Marijuana was published on and updated on August 30, 2022 . Medical facts in this article was checked and article was medically reviewed by our . Author of this checked article is
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