How Long Can Marijuana Be Detected in a Mouth Swab Drug Test?

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Written by Joseph Okonofua on 08/12/2023.
Data Last Updated: 05/30/2024.

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One of the biggest concerns you can have as a cannabis user is how long the drug stays in the body system. With cannabis still classified as a Schedule 1 drug under federal law, there are certain times when it might become problematic to test positive for marijuana. So if you are looking for accurate details concerning how long after use marijuana can still be detected in your body, you have found the answers you seek. In this article, we will explore the various factors that affect marijuana detection times, and the reliability of mouth swab marijuana detection tests and also provide essential tips on how to speed up the marijuana metabolism. 

How Long Does Marijuana Stay in the Body?

How Long Does Marijuana Stay in the Body

Detecting marijuana in the body involves identifying its active compound, delta-9-tetrahydrocannabinol (THC). THC is responsible for cannabis’s psychoactive effects and is the primary target of drug tests. When someone consumes marijuana, THC is metabolized by the body and can be detected in various bodily fluids and tissues.

Now, the duration for which marijuana remains detectable in the body varies from person to person. However, on average, THC can be detected in urine for up to 30 days after use, while it may be present in blood for a shorter period of 1 to 7 days. Hair tests can reveal marijuana use for as long as 90 days, and saliva tests may detect it for up to 72 hours after consumption.

THC Absorption and Distribution

THC Absorption and Distribution

To understand how long marijuana stays in the body, it’s essential to grasp the metabolism of THC. When marijuana is smoked or vaporized, THC rapidly enters the bloodstream and reaches peak levels within minutes. This is why the psychoactive effects are felt almost immediately. After a while, the body then begins breaking down THC into metabolites, which are stored in fat cells and gradually eliminated over time, affecting detection windows.

Cannabis drug testing targets these metabolites. If the metabolites are present in the sample, the test is positive. If they are not present, the test is negative. Nonetheless, there are certain factors that determine the marijuana detection window.

What Are the Factors Affecting Marijuana Detection Window?

What Are the Factors Affecting Marijuana Detection Window?

Several factors influence how long marijuana remains detectable in the body:

1. Frequency and Amount of Marijuana Use

Regular users tend to have longer detection times as THC and its metabolites accumulate in their system. Occasional or first-time users do not have to worry about cannabis metabolite accumulation.

2. Method of Consumption

Smoking or vaporizing marijuana leads to faster THC metabolism and shorter detection times compared to consuming edibles. This is because THC is absorbed into the bloodstream more quickly when it is inhaled than when it is ingested. 

When marijuana is smoked or vaporized, THC enters the bloodstream directly through the lungs and reaches peak levels within minutes but when edibles are consumed, THC must first pass through the digestive system before it enters the bloodstream. This process can take up to two hours, which is why edibles have a slower onset.

3. Individual Metabolism and Body Composition

If you are one of those gifted with a fast metabolism, then your body will eliminate THC and its metabolites from its system more quickly than people with slower metabolisms.

4. Body Fat Ratio

Body fat percentage is another factor that can affect THC detection times. THC is a fat-soluble compound, which means that it binds to fat molecules in the body. This makes it more difficult for the body to eliminate THC, and it can remain in the system for longer periods of time in people with higher body fat percentages.

While the above are the factors that affect the marijuana detection window, the time frame actually differs per test. 

How Does Mouth Swab Marijuana Test Work?

How Does Mouth Swab Marijuana Test Work?

It works using oral fluids as a test sample for compounds of THC, which are inhaled when THC is smoked. The test collector is usually swabbed around the entire mouth to collect THC deposits and residue. Compared to other testing methods, the mouth swab test is very convenient, which is why it is often used in pre-employment screening, workplace testing, and random drug testing programs.

The test result is influenced by the frequency and dosage of cannabis use. Nevertheless, the detection window may be shorter if the mouth has been washed, because THC is removed from the mouth by saliva and degrades over time. This type of drug testing is quick and easy to administer and can provide accurate results within minutes.

What is the Detection Window for Marijuana in Mouth Swab Tests?

When it comes to testing for marijuana, the detection window for a mouth swab test is relatively short. While a urine test can detect marijuana use for up to 30 days after use, a mouth swab test can only detect use within the past 24-48 hours. 

Mouth Swab vs. Urine Test for Marijuana

What is the Detection Window for Marijuana in Mouth Swab Tests?

When considering methods for testing marijuana use, both mouth swabs and urine tests are commonly used. However, there are some key differences between the two. 

  • Accuracy: Mouth swab tests are known for their accuracy in detecting recent marijuana use, making them a suitable choice for situations where recent usage is a concern. Meanwhile, urine tests can produce false positives under certain circumstances.
  • Detection Window: Mouth swab tests have a shorter detection window compared to urine tests, typically spanning a few hours to a couple of days after marijuana use.
  • Convenience: The simplicity of collecting a saliva sample with a swab makes mouth swab tests a convenient option, reducing the likelihood of tampering or adulteration.
  • Rapid Results: Mouth swab tests provide quicker results, typically within minutes, making them ideal for scenarios requiring immediate testing.

Mouth Swab vs. Blood Test for Marijuana

Mouth Swab vs. Blood Test for Marijuana

Blood test is a very accurate testing method but it is far more invasive than the mouth swab test. Here are the differences:

  • Accuracy and Precision: Blood tests are known for their high accuracy and precision in detecting THC in the bloodstream, making them the gold standard for many legal and medical purposes. It has a higher accuracy rate than the mouth swab and urine test
  • Invasiveness: Blood tests are invasive and may be uncomfortable for the person being tested, which can be a drawback compared to mouth swab tests.
  • Detection Window: Blood tests can detect THC for a more extended period (up to seven days) compared to mouth swab tests, making them suitable for historical drug use detection.

Pros and Cons of Mouth Swab Marijuana Drug Tests

Pros and Cons of Mouth Swab Marijuana Drug Tests

Like any method of drug testing, there are both pros and cons to using a mouth swab test:


  • Non-invasive and convenient.
  • Can detect a wide range of drugs in addition to cannabis.
  • Can be performed in a variety of settings.
  • Relatively quick results.


  • Shorter detection window than other testing methods.
  • More prone to false positives than other testing methods.
  • May not be able to detect chronic drug use.

Is Mouth Swab Marijuana Test Accurate?

Mouth swab drug tests are generally considered to be highly accurate in detecting the presence of THC and its metabolites in the body system. However, as earlier stated, mouth swab tests are generally as accurate but can produce false results, especially if the person being tested has recently used certain foods or beverages, such as mouthwash, candy, or coffee. So it is important to keep these factors in mind when interpreting the results of a mouth swab drug test.

Tips for Speeding Up Marijuana Detox

Tips for Speeding Up Marijuana Detox

If you need to clear THC from your system quickly, here are some tips you can follow:

  • Drink plenty of water to flush your system. While this won’t guarantee a negative result, it may slightly dilute the concentration of THC metabolites in your urine.
  • Avoid repeated use of marijuana and other drugs.
  • Some individuals take niacin supplements, believing it can help speed up THC metabolism. 
  • Exercise regularly. Engaging in intense cardiovascular exercise can temporarily increase your metabolic rate and may help burn fat cells where THC is stored.
  • Eat a healthy diet with plenty of fruits, vegetables, and whole grains to accelerate the elimination of THC from your system.

Note that detoxification may not guarantee immediate results, so the best approach is abstinence for a period matching your personal detection window. 

When is it a Crime to Use Cannabis in the United States?

When is it a Crime to Use Cannabis in the United States?

Although 38 states and the District of Columbia have legalized marijuana for medical use, and 21 states and the District of Columbia have legalized marijuana for recreational use, there are certain situations where using or possessing marijuana can become problematic. For example:

  • Driving under the influence of marijuana;
  • Possessing marijuana on federal property;
  • Using marijuana on federal property;
  • Transporting marijuana across state lines;
  • Selling or distributing marijuana without a license (even in states where marijuana is legal); and 
  • Using marijuana while on probation or parole (except it is legal by law in your state).

Final Thoughts

Now that you know how long marijuana can be detected in a mouth swab drug test, you can take the necessary steps to ensure you stay within the acceptable range. Whether you’re a regular user or an occasional user, it’s important to keep in mind the factors that affect marijuana detection times. By understanding these factors, you can take steps to speed up the marijuana metabolism and avoid testing positive for marijuana. 

Always do your best to stay informed of the legal restrictions in your area to make informed decisions regarding marijuana use. Additionally, when faced with legal issues related to marijuana, seeking legal counsel is advisable.


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