How Long Does THC Stay In Your System?
4 min

How Long Does Thc Stay In Your System?

4 min
Lifestyle News

While cannabis laws are getting more lax, drug testing by companies and law enforcement can still be a problem for many. But no need to panic! Learn how long THC stays in your system, and discover ways to help pass a drug test in this article.

Despite cannabis laws recently becoming more relaxed in many countries, drug testing is paradoxically on the rise. Previously conducted mainly by employers in the US, large companies in Europe are now also starting to screen employees for drug use, which includes cannabis.

Although the effects of smoking cannabis fade quickly, its metabolites can be detected in the body for several weeks and sometimes even longer. However, how long THC (the psychoactive compound in cannabis) stays in your system, and for how long it can be detected, depends on various factors. Understanding these factors are key to passing a drug test.

How Does Marijuana Affect The System?


Marijuana contains hundreds of different compounds, but THC is the ingredient that is responsible for getting us high. THC quickly enters the bloodstream when you smoke or vape marijuana. With other consumption methods, such as edibles, it can take much longer for THC to be absorbed and the effects to be felt.

The effects from smoking marijuana, feeling high or stoned, don't last long, but there can be some lingering effects from consumption for up to 24 hours. After smoking, the  THC in the blood is rapidly broken down in the body, where it is modified into so-called metabolites.These metabolites accumulate in the body until they’re slowly eliminated.

How Long Can Marijuana Be Detected In Your System?

There is no straight answer for how long THC may stay in one’s system. This can vary from person to person, depending on their fitness level, metabolism rate, diet, and even gender and ethnicity. Another big factor for detecting THC in the body is the type of marijuana that someone consumes. Some cannabis strains can be much more potent and have higher levels of THC than others. The different types of drug tests also vary when it comes to how long they are able to detect THC.

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Not everyone metabolises THC at the same rate. Since THC embeds itself in the body’s fat tissue, this means that people with higher body fat store more THC and THC metabolites as compared to a thinner person. Once THC is embedded within the fat tissues, it will be eliminated from the body very slowly. Depending on how much marijuana has been consumed, it can be stored for weeks, if not months.

How long THC can be detected also depends on how often you use marijuana. Those who smoke frequently retain the metabolites much longer than people who smoke only occasionally.

Thc Elimination - Averages Based On Studies


A study performed in 2001, in which researchers examined 52 volunteers, found that the average time for THC to clear from an individual is 4.9 days, while some of the volunteers in the study needed up to 18 days. A previous study from 1992, which looked at occasional and frequent marijuana users, found that urine samples from occasional users tested positive for THC for up to three days after use. The frequent users in the study tested positive for much longer—up to 12 days.

Smoking Frequency Is A Major Factor

These test results confirm that smoking frequency is the biggest factor for how long marijuana can be detected in the body. If someone smokes marijuana only rarely, THC-COOH, which is the metabolite tested for in urine screenings, can usually not be detected after three days.
Frequent users can take a week or longer after smoking until they will test negative. For heavy users, this figure is much higher.

Types Of Drug Tests


A drug test determines how much of a drug is in your system. This is done by analysing biological samples such as urine, blood, saliva, hair, or sweat. Common drug tests today check mainly for metabolite THC-COOH, rather than for THC itself.

Each particular test type has different detection windows for marijuana use. Hair testing has the longest detection window, and can recognise THC metabolites for up to 3 months after use. The detection window is the period that a person can test positive after consuming marijuana. The threshold of a test is the measured amount of THC-COOH that determines if a person is positive or negative.

  • Urine Test

Urine testing is the most common. For urine drug testing, which is commonly done by employers, the threshold is normally 50ng/ml. Everything below means the test is negative. Keep in mind that the threshold may change depending on the employer or organisation. 50ng/ml is not set in stone.

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  • Blood Tests

Blood tests can detect active THC in the bloodstream in addition to the THC metabolites. They are often conducted to see whether someone used marijuana recently, such as after accidents or as part of an autopsy. Blood drug tests can register positive for up to 12 hours after marijuana use. They can detect THC amounts as small as 1ng/ml in frequent users for up to 7 days.

  • Hair Drug Tests

Hair drug tests have the longest detection window among all types of drug tests. This is because the body deposits THC into the hair, where it stays as the hair grows. Hair drug tests are more expensive than other tests, but are sometimes used when a company or an organisation wants to test for a longer history of use. Hair testing commonly employs a threshold of 1pg/ml.


  • Saliva Drug Tests

Saliva drug tests have become popular because they are precise, easy, and less expensive than other testing methods. Saliva tests are sometimes done as a roadside test by police when checking for impairment. Just as with blood testing, saliva tests can show whether someone just recently consumed marijuana. They can detect THC for up to 24 hours after consumption, and THC metabolites for several days.The threshold level for saliva drug tests is normally 2ng/ml.

  • Sweat Tests

Marijuana sweat tests are done as a way to monitor drug use for a certain amount of time. This is normally done with a patch that is applied to the skin, where the patch would remain for a week or two. However, sweat tests have some limitations: THC levels can vary greatly, depending on someone’s activity, environment temperatures, and other factors.

Aside from that, not all people have the same level of transpiration, which means that THC levels can vary from person to person. Marijuana sweat tests using skin patches are sometimes used in drug treatment programs. They can only detect quite recent marijuana use. Their threshold is typically 1ng/patch.

Overview Of How Long Thc Can Be Detected For Each Test (On Average)

Urine Test
  • Single use: up to 8 days
  • Regular use: up to 30 days
  • Heavy use: up to 77 days
Saliva Test
  • Single use: up to 24 hours
  • Regular use: up to 72 hours
  • Heavy use: up to 1 week
Blood Test
  • Single use: up to 24 hours
  • Regular use: up to 3 days
  • Heavy use: 1 week or longer
Hair Test
  • Up to 3 months
Sweat Test
  • A few hours before patch removal

How To Get Thc Out Of Your System

If you’re facing an upcoming drug test, there are ways to help speed up the elimination of THC from your body. But know that there are no sure ways to guarantee that your system will be THC free (apart from abstinence) - contrary to anecdotal reports that you might find on the internet. The best way to beat a drug test is to abstain from marijuana prior to the test!

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Some tricks to beat a test, such as drinking a lot of water or heavy exercise, may possibly help you somewhat with the elimination of THC. However, they can’t ensure you will pass a test. If you’re unlucky, it may even happen that your test is rejected for being too diluted. If you want to play it safe, don’t consume marijuana when an important drug test is coming up.

Can Cbd Cause You To Fail A Drug Test?


Pretty much all drug tests screen for THC and THC-COOH. This metabolite has very little crossover with other cannabinoids, such as CBD and CBG. This means that CBD is normally not an issue for drug testing.

When you’re taking CBD supplements, make sure that the product contains absolutely no THC and you should be fine. Know that there can be a small risk for false positives should you take excessive amounts of CBD. But if you stick to the required dosage, you don’t really need to worry.


Written by: Georg
Based in Spain, Georg spends a lot of his time not only geeking out at his computer but in his garden as well. With a burning passion for growing cannabis and researching psychedelics, Georg is well versed in all things psychoactive.

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