How Long Does Marijuana Stay In Your System

How long does Marijuana (THC) stay in your system?

Marijuana has been noted as the most frequently used drug in the United States of America.

The CDC has expressed that 50 million people have at least tried the drug. Another study showed that more than 30% of citizens use marijuana. (5)

Many employers require testing for marijuana before entering into a contract. This often times is due to workplace safety. Due to the recent acceptance of recreation marijuana use this at times can place the employer as well as the employee in a difficult situation.

It is important that both employee and employer be knowledgeable to the details. (2) In this article you will read about the types of testing done for marijuana, the amount of time it is shown in your system and how to clear the system or detox from the drug.

How long is Marijuana detected in the body?

  1. The length of time that the drug can be detected in your body may depend on the frequency of use.
  2. If the use is infrequent then marijuana has been noted to be detected from 2-5 days after use.
  3. If consumption is very frequent it may be detected for as long as 15 days after consumption in the urine.
  4. High body fat or who would be considered chronic users detection can be as long as 30 days(6)

Testing Methods for Marijuana (THC)

Urine tests or Urinalysis


Urinalysis has been used for many years to test for marijuana use.
It is often the method used by most places because it is the easiest and does not require laboratory experience to use.

Urine testing does not look for the parent drug itself but is testing for the metabolites of it which is called THC-COOH. This metabolite is produced when by the liver when it breaks down THC.


THC is known as the parent drug and I what causes the high. THC-COOH is the metabolite and stays longer in the system. If used correctly urine tests can show a 95% accuracy rate and only as much as a 4% false-positive. (5)



It is obvious that it is not as invasive as other methods and is also more economical. Above all, it is the method that requires the least amount of time to get results. This method is based on the fact that THC is stored in the fat and when burned is filtered out through the urine.(1)THC in urine


which include being easily altered by the user, may be embarrassing to collect with supervision, and the user may dilute their urine with increased fluid intake. (8)

Saliva test


Saliva tests have been noted to detect marijuana from 12-72 hours after use of the drug. This wide variability depends on if the test was done on-site or in a laboratory. Saliva testing differs from urine tests in that it actually shows the parent drug and not its metabolites. (6)THC in saliva


This process is considered safer due to the fact that is not invasive. It is also better than urine testing because the collection is easier to supervise and its results are less likely to be altered.  Saliva tests have been noted to have the highest accuracy of positive testing. Currently you can find easy to use devices which collect the specimen and exam it.


low levels can be the result of passive exposure rather than actual consumption of the drug.  (8)

Hair follicle test


Although this is often referred to as hair follicle testing the follicle it is not actually used as part of the test. The first one and half inch from the base of the scalp is used for testing. This test is looking for metabolites deposited by the blood stream rather than the parent drug.THC in hair


Marijuana can be detected in hair for up to 90 days after use. (6)


the same metabolites tested are also present in cannabis smoke. Therefore the results may only express the presence of marijuana smoke near the person being tested and not necessarily consumption of the drug. This may be a cause for many false positives.

More than one study has shown that metabolites of the parent drug may not be incorporated through the bloodstream and therefore a positive test does not prove consumption. (8)

Blood test


Blood testing for marijuana is frequently done for a more accurate test result. The parent drug can be noted in blood as quickly as minutes after consumption. This is likely the only method of testing that can really show the degree in which the drug is consumed. (5) Some of the common clinical abbreviations of the blood tests include EMIT and GCMS.THC in blood serum


Blood samples can show the existence of the drug from 12-24 hours after use. If use is chronic or heavy it can be detected in the blood for up to a week.


The test is invasive and can cause pain. Also in order to get appropriate results you need laboratory experience. This manner of testing and also be very expensive. (6, 8)

How to Detox your body from Marijuana

Methods available

There are many detox methods that can be found online or in stores. These may include and are not limited to types of shampoo, mouthwashes, capsules or tablets, and even drinks.


The issue with many of these so-called detoxes is that they may also be detectable in drug testing exams. The alteration to the test due to a “detox method” can sometimes be very obvious in the above-mentioned tests. Other detox methods focus on flushing the drug out of the system for urine testing.

These methods mainly consist of teas or drinks which encourage a lot of liquid intake and therefore cleanse or dilute the urine.

Again the issue with this method is that it also dilutes other normal urine counts such as creatinine. This makes is obvious to the technician who is doing the test that there has been an attempt to dilute or flush the system. This cannot be considered as a positive test but the technician can call it unacceptable and require retesting.

The facts

The best way to pass any of the above tests is to abstain from the use of marijuana a bit longer than the drug can be detected in the system by the suggested means of testing.

References :


Published by Dr. Raj MD under Pharmacy.
Article was last reviewed on August 6th, 2018.

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