How long does THC remain in the body?

Virtually all cannabis use leaves traces of THC in the human body. The time it takes for the body to eliminate traces of cannabis depends on a number of factors, including an individual’s metabolism and usage.

The THC leaves traces in saliva, urine, blood, and hair, but the length of time a user may test positive for cannabis varies.

Summary: THC Detection Times by Test Type

The duration varies depending on metabolism, body fat percentage, and the concentration of THC consumed.

THC and THC-COOH

THC, the cannabinoid which is responsible for cannabis’s psychoactive effects, is quickly eliminated from the body within a few hours. Its presence, however, can be detected by testing for THC-COOH, a metabolite produced by the liver when it breaks down THC. And THC-COOH stays in the body for waaaay longer.

THC and its metabolites are fat-soluble and accumulate in fat stores throughout the body. These molecules are then slowly released over time, resulting in a significantly longer period for the body to clear traces of cannabis, particularly for chronic users.

In France, the substances tested for in cannabis screening are delta-9-THC (THC) and 11-carboxy-THC (THC-COOH).

How long does it take for THC to leave the body?

The length of time THC remains in the body—and thus the duration for which it can be detected—depends, among other things, on:

• of your weight
• of your body fat percentage
• quantities consumed
• how often you consume it

Since these factors vary from person to person, there is no set rule, but certain general trends can be identified. The official detection times for THC are as follows.

How long does THC stay in saliva?

The THC is eliminated from saliva within 1 hour, but it can be detected up to 12 hours after the last use. In cases of heavy or daily use, some users have THC in their saliva for between 24 hours and 8 days.

A 2014 study A study on cannabinoids in saliva revealed that THC metabolites were detectable in the saliva of occasional users for one to three days and in chronic users for up to 29 days.

How long does THC stay in the blood?

Within seconds of inhalation, active THC can be found in the bloodstream and can be detected in plasma for several hours, depending on the frequency of use and the amount consumed. Plasma THC concentrations peak within just 3 to 8 minutes after inhalation and then decline rapidly, with a half-life of approximately 30 minutes.

THC can be detected in the blood for up to 2 days after the last use of cannabis. Heavy cannabis users may test positive for cannabis for up to 1 month after stopping use, as THC metabolites remain detectable for several weeks after use.

When taken orally (edibles, capsules), the peak plasma THC level is reached later (between 1 and 3 hours after ingestion), and the detection times in blood and urine are comparable to those following inhalation, or even slightly longer due to more gradual absorption.

How long does THC stay in urine?

Cannabis can be detected in urine. Depending on usage patterns, the following has been observed:

• Occasional smokers (3 joints in the evening) could test positive for 1 to 6 days
• moderate smokers, 7 to 13 days
• frequent smokers, at least 15 days
• heavy smokers, at least 30 days
• Some heavy smokers have had traces of THC detected in their urine up to 90 days after quitting

How long does THC stay in your hair?

It takes 7 days for THC to show up in hair. Hair, on the other hand, traces back a 90-day period everything that goes on inside your body.

There is growing evidence that methods for detecting THC in hair are unable to accurately detect cannabis.

Some research suggests that THC and THC metabolites can be transferred to the hair follicles of non-users through hand contact, sweat, or smoke. For example, if someone smokes a joint and exhales near a person who does not use cannabis, THC can be transferred to the non-smoker’s scalp or hair. However, the likelihood of detecting THC in the hair increases significantly with more frequent use.

A 2015 study revealed that, after giving participants 50 milligrams of THCA every day for a month, no THC was found in the hair samples, but THC-COOH was still detected.

How long does it take for THC to break down (metabolize)?

The THC that enters your body is absorbed into the bloodstream. Some of the THC is temporarily stored in organs and fatty tissues. In the kidneys, THC can be reabsorbed into the bloodstream.

THC is broken down in the liver. It has more than 80 metabolites, but the most important ones are 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol) and THCCOOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol).

Drug screening tests look for these metabolites, which remain in your body longer than THC. Eventually, THC and its metabolites are excreted in urine and feces.

Factors that can affect how long THC stays in the body

Various factors can influence how long THC remains in the body.

Dosage

The more THC you consume, the longer it will take your body to eliminate the THC and its corresponding metabolites.

Consumption frequency

The duration and frequency of use have a significant impact on how long cannabis remains in your body. Most research on cannabinoid detection shows that THC remains in the bodies of regular users for much longer than in those of occasional users. The frequency of cannabis use is also a significant risk factor for developing cannabis withdrawal symptoms.

Genetics

Genetics also affects how long THC remains in the body. For example, people inherit different variants of the cytochrome P450 enzyme superfamily, which metabolize THC in the body, leading to the elimination of cannabis through urine.

Grease

The amount of body fat is also an important factor. The THC-COOH metabolite is fat-soluble and binds to fat molecules, where it can be stored for a long period of time. Similarly, exercise can also affect the levels of detectable THC metabolites. When fat is burned, THC that has been stored in fat can be released into the bloodstream and excreted by the body in urine or feces.

Metabolism

A body with higher metabolic rates can break down cannabinoids more quickly, shortening the time that THC and its metabolites remain detectable in the body.

How can I get rid of THC faster?

There is no miracle method for significantly speeding up the elimination of THC. The liver metabolizes THC at its own pace, and most «detox kits» sold online simply dilute the urine—which can result in an invalid test result (too low a creatinine concentration) rather than a negative result.

That said, certain actions can naturally speed up the process slightly:

Stop using : This is the only sure way. The sooner you stop before a test, the more time metabolite levels have to decrease.

Staying Properly Hydrated : Drinking enough water (1.5 to 2 liters per day) helps flush THC metabolites out of the body through urine. Be careful not to overhydrate: urine that is too diluted can invalidate a test and make the result questionable.

Engage in moderate physical activity : By burning fat, exercise releases THC-COOH stored in adipose tissue, which can paradoxically cause a temporary spike in the levels of metabolites in the blood and urine before they are eliminated. Therefore, exercise should be avoided within 48 hours before a test.

Power supply : A high-fiber diet promotes the excretion of metabolites in the stool. Approximately 15 to 30% of THC-COOH is eliminated in the stool.

What doesn't work : Cranberry juice, apple cider vinegar, «detox teas,» creatine, and niacin have no proven effectiveness in eliminating THC. Some masking supplements can alter test results and are detected by laboratories.

Is there anything you can do to speed up your metabolism?

There isn't much you can do to speed up the time it takes for THC to leave your system. The only thing that's certain is that the’Quitting THC will reduce your tolerance to cannabis.

Once THC is in your body, it takes time for your body to break it down. Exercising, eating healthy, and staying hydrated can help, but not dramatically.

There are a number of detox remedies and kits available online. Many require drinking plenty of water to dilute the urine, and then using herbal supplements such as creatinine or vitamin B-12 to mask the dilution.

These kits do not work reliably.

How can you tell if you still test positive for THC?

The easiest way to find out if you still test positive for THC is to get tested, either with a home test kit or by getting tested at a clinic. These tests can be expensive and aren’t covered by insurance, but they can help you understand your current status, particularly by providing a precise and accurate measurement of THC levels in your saliva or urine.

Can you test positive for THC if you use CBD?

It all depends on what you mean by « CBD«. If it’s a pure cannabidiol extract—such as an isolate—or a broad-spectrum oil (containing 0% of THC), then no, you cannot test positive for THC by consuming CBD.”.

If, on the other hand, you consume «CBD» in the form of flowers or’full-spectrum CBD oil (with -0.3% of THC), you could potentially test positive for THC, for example during a traffic stop involving a saliva test.

See our article on the CBD and drug tests.

Are cannabis screening tests effective?

The reliability of cannabis screening tests depends on several factors, including the type of test, the frequency and amount of cannabis use, individual metabolism, and the sensitivity of the testing method. Although cannabis screening tests can provide valuable information, it is essential to recognize their limitations:

Detection window: Different types of cannabis screening tests have varying detection windows, ranging from a few hours to several weeks. Urine tests, for example, can detect THC metabolites for several days or even several weeks after cannabis use, whereas saliva tests generally have a shorter detection window.

Cross-reactivity: Some cannabis screening tests may cross-react with other substances, leading to false-positive results. For example, certain over-the-counter medications, dietary supplements, and even poppy seeds can trigger positive results on cannabis screening tests.

Thresholds and Sensitivity: The sensitivity of cannabis screening tests can vary depending on the testing methods and laboratories. Detection thresholds for THC metabolites can vary, which affects the likelihood of a positive result.

Metabolism and Individual Variability: Individual metabolism and physiological factors can influence the rate at which THC and its metabolites are processed and eliminated by the body. Factors such as body mass index (BMI), hydration levels, and liver function can influence the results of cannabis screening tests.

In France, it is estimated that screening tests produce 20% false negatives and 30% false positives.