How Long Does Marijuana Stay In Your System?

Quick answer:

Calculate The Duration Time For Marijuana (THC) To Last in Your System From Last Use:

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Light Occasional User
Regular User
Chronic User

in Urine

in Blood

in Saliva

in Hair



How Long Does Marijuana Stay In Your System?

Long Answer:

One of the most common queries to arise among the regular smokers of weed, as well as, those who have smoked it only occasionally is about how long does marijuana stay in your system.
This question can be of particular relevance to you if you happen to have smoked weed in the past few days, and need to appear for a drug test in the immediate future. The reason behind the greater relevance of this question to you is that unlike most other intoxicating substances, the weed refuses to leave its traces in the body of the smoker that easily. Thus, you are likely to be left wondering about duration of time during which the marijuana stay in your system. All the hokum promises that you most likely to encounter everywhere on the internet regarding quick fix solutions available to clear your system of traces of weed in a jiffy are nothing but gibberish.

The problem that smokers of weed face while trying to clear a drug test is that the active chemical of marijuana and its metabolized by-product lingers in the body for a very long time. The duration of this staying period increases with the frequency at which the smokers have smoked it. Therefore, heavy users are going to have to wait longer for all traces of weed to leave their system. Even then, you will not be sure about how long does marijuana stay in your system because certain parts of the body such as hair follicles and brain tissue can contain traces of the active chemical for years.

One of the active chemicals that weed contains is tetrahydrocannabinol or THC, which is a type of fat-soluble chemical. Therefore, it can remain stored in the fat cells of the body, and this explains the extreme durability of this chemical inside the human body. THC can reside within various vital organs of the body such as brain, liver, or the kidneys, as well as, other parts of the body containing fat cells. The fact that this chemical uses some of the most important organs in the body as its storage place makes it even more difficult to remove all its trace from the body. However, worrying only about how long does THC stay in your system is not going to suffice because a metabolized by-product of this chemical by the name of 9 carboxy tetrahydrocannabinol is the chemical that detection tests use as their target.

The marijuana detection tests are unable to pinpoint the actual date of consumption of this drug in a precise manner, but can be quite accurate by calculating the half-life of the by-product of THC. This helps the professional to calculate the duration during which the active chemicals of weed have remained within the test sample of any suspected weed smoker. However, you are likely to calculate on your own the duration during which you need to abstain from smoking weed to come clean in any drug test specifically designed for detecting it. This is because the duration of time, which the marijuana stays in the system, depends upon a number of factors. You need to take into account this factors in the right proportion of the influence they exert to arrive at a number that can accurately foretell the time after which there will be no traces of weed left in your system. However, this is practically impossible because of the dynamic nature of the human body. Among the most important of factors to determine about how long cannabis stay in your system, is the frequency at which you smoke it. This is because the half-life of the byproduct of THC to remain within the system of smoker greatly increases in case of person who smokes weed regularly. Thus, a person who smokes cannabis only occasionally, such as at the frequency of once every week is likely to have the byproducts of THC leaving his or her system within 10 days or so. On the other hand, a regular smoker is likely to take around 45 days to get all traces of weed out of their systems. Moreover, heavy smokers will find it still harder to make their system free from traces of weed, and will take at least 90 days to remove most of its traces. However, some traces of the byproduct can remain lodged in the brain cells, and hair follicles that are particularly difficult to remove.

Case Studies:

In 2011, a study published in the ‘Journal of Pharmacy and Pharmacology’ saw researchers conduct tests to determine the duration of cannabis in the body. They made the subjects ingest cannabis resin to enable the researchers to examine the forensic aspects of the metabolism and excretion of cannabinoids. They used the RIA to show the major plasma metabolites. Results show that THC metabolites could be detected within the blood for upto 5 days and within the urine for upto 12 days after a single dose.

Another study in 2004 published in the ‘Therapeutic Drug Monitoring Journal’ saw Scientists conduct tests to determine the half-life of the cannabinoids after smoking of cannabis joint varying between 5mg and 30mg. They conducted these tests on 52 volunteers admitted to a detoxification program. They took the urine samples as well as blood samples to arrive at the plasma concentration. Results show a lower half-life in occasional users and a longer period of 3 to 13 days in case of regular users. After oral intake, detection in urine took longer time.

These studies indicate that THC, the metabolite of marijuana can be detected within the blood and urine for many days after last use, which shows that THC metabolites have a good potential for indicating recent cannabis use, so it’s no wonder that most marijuana drug tests are based on detecting THC within a sample. The studies also indicate that occasional users of marijuana can metabolize THC quicker than regular users, which may be down to that fact that THC is known to attach itself to fat cell within the body, and hence its traces remain in the body for much longer in regular users.


Factors to Consider in Determining How Long Does THC Stay In Your System:

Another factor that greatly influences the longevity of the duration of marijuana stay in the system is the amount of body weight. A person with a greater percentage of body fat will find it much more difficult to become completely free from the traces of smoking weed. This is because both THC and its byproduct are fat-soluble chemicals, which make use of the fat cells as their storage points, and can linger in those cells for long periods. Moreover, a person with higher fat content will be providing greater amount of storage space for the active chemical. Thus, the physical fitness of a person can play a huge role in deciding the duration of the stay of the active chemicals of weed in his or her system.

Moreover, the rate of metabolism also plays an important role in removing any intoxicating agent from the system. This assumes an even greater role in case of smokers of weed because of its persistence in staying within the body of its users. Thus, a robust metabolism is necessary to breakdown the active chemical of weed and for the body to expel it at the earliest. In addition to that, a robust metabolism also helps in preventing the buildup of fat cells inside the body. Therefore, it is going to help on two fronts to make the system better suited to remove all traces of weed. Thus, weed smokers need to consider this as well, while trying to answer the query about how long does marijuana stay in your system.

Tolerance level towards toxins is an important determining factor for the duration of traces of weed to remain in the system as well. Drinking a lot of fluids, and following an active lifestyle are helpful in flushing out the toxins created as byproduct of metabolism of the active chemical contained in marijuana.


Marijuana THC Drugs Test:

However, many people try to fudge their cannabis urine test with the misconception that drinking a lot of fluids is going to help in appearing clean. This is not true because excessive drinking of water is going to make the urine too dilute. Since the urine tests use acceptable range of other chemicals as the reference parameters, a diluted sample of urine is going to screw with those measurements as well, and appear as an intentional attempt at fudging the test. Thus, it becomes essential that you try to make your calculation right about the longevity of marijuana in your system, and come for the test in a clean state.

If you think clearing the urine tests is difficult, the prospect of going for the blood tests is going to intimidate you even more. This is even truer if you happen to be a regular smoker of weed. The more frequently you smoke weed, the longer period it is going to take for your system to effectively clear it out of your body. Therefore, the best option is not to opt for smoking it at all. This is because some of the detection tests can give you away even years after you have gave up smoking weed. Since the byproduct of THC accumulates in the hair follicles, those that have survived for the period of your smoking still contain traces of that chemical. Therefore, the real answer to the query about how long does marijuana stay in your system is too long to bust any drug test that you appear for in the foreseeable future.

If you are serious about appearing clean on drug tests, then seriously plan for its days and months in advance. The longevity of the traces that weed will leave in your body makes such planning necessary. Exercise regularly to shed excess fat, and shave your hair at least once because they are going to give you away before a hair test. If you are occasional smoker, then feel confident about clearing the drug test. However, keeping all the factors in mind that determine how long marijuana stay in system will help you in facing such drug tests with confidence.

Some street names of marijuana: Cannabis, Ganja, Weed, Hemp, Astro turf, Bhang, Blunt, Boom, Chronic, Dagga, Dope, Gangster, Grass, Herb, Home grown, J, Kiff, Mary Jane, Nederweed, Pot, Purple Haze, Reefer, Roach, Smoke, Skunk, Super Skunk, Texas tea, White, Widow



  • Metabolism of Cannabinoids following oral ingestion – 2011 – Journal of Pharmacy and Pharmacology – by B. Law, P. A. Mason, A. C. Moffat, R. I. Gleadle and L. J. King

  • Detection Times of Drugs – 2004 – Therapeutic Drug Monitoring Journal – by Verstraete AG