cannabis buds on watch
How long does cannabis stay in your system and what can you do about that?

We have some bad news: cannabis can stay in your system for quite some time. But, the rate at which you clear cannabis from the body varies from person to person. 

Depending on your body composition, the amount you consume, and your frequency of consumption, it may take up to a full month to fully detox from the plant.

How Long Does Cannabis Stay in your System?


drug test report
Most U.S. employers test for cannabis.

Unlike alcohol and other intoxicants, cannabis compounds can stay in your system for quite a while.

"The common lore is about a month," explains Dr. Jordan Tishler. Tishler is a Harvard-trained Holistic Care Specialist with a particular interest in medical cannabis. He's also the founder of Inhale MD, which specializes in cannabis therapeutics in the Boston area. 

"But, I've seen patients take up to three months to clear." 

This "common lore" is backed by some real evidence.

A 1989 study, for example, found that cannabis compounds detected for up to 25 days after smoking in heavy cannabis consumers--grim news for medical cannabis consumers or dedicated enthusiasts.

Not all estimates are as lengthy, however. Mayo Medical Laboratories offer a more generous timetable:

  • Single-use: 3 days
  • Moderate Use: 5 days
  • Daily Use: 10 days
  • Chronic Heavy Use: 30 days

It is important to note, however, that these estimates are merely rough generalizations. The actual amount of time cannabis compounds stay in your system varies significantly from person to person.

Why Does THC Stay in your System so Long?


hand holding green leaf cannabis
How do you feel about workplace drug testing?

Cannabinoids are fat-soluble lipids. This property means that it may take longer to clear cannabis from our system than other, water-soluble compounds.

As Tishler explains, "Cannabinoids are absorbed into fat tissue readily, not so much in the blood."

"This means we effectively store them in our fat," he says. "Then they leach out slowly over time, leading to persistent low blood levels."

Cannabis compounds like tetrahydrocannabinol (THC) take a while to clear your system because excess THC is stored in fat and then re-released into the blood as that fat burns.

As a result, low levels of THC metabolites will persist in the blood for a relatively long amount of time. THC metabolites are natural derivatives of THC. The body creates these derivatives as it processes the cannabinoid.

A small portion of THC metabolites leaves the body via urine. These metabolites are detectable in a urinalysis. 
A urinalysis tests urine for the presence of drug metabolites and is the most common type of drug testing.

For Some, Cannabis Stays in Your System Longer Than Others


Our bodies store the THC we consume, recognizing it as a beneficial molecule.

Some people may clear cannabis from their system faster than others. Several factors may influence how long THC stays in your system, including body composition and the total amount of cannabis you consume.

Body Composition

Body composition may influence how long cannabis stays in your system. Cannabis compounds accumulate in fat cells. As such, cannabis compounds may take longer to clear in people with more body fat.

Amount Consumed

The amount you consume also contributes to how long THC stays in your system. The more cannabis you consume, the longer it will take to clear cannabis compounds from your body.

Frequency of Consumption

As Tishler suggests, those who consume daily will likely face longer clearance times than those who enjoy the herb only on occasion.

Even with these factors in mind, however, every individual will still process cannabis at an individual rate.

"It's not entirely clear why it takes longer for some than others to clear," says Tishler. "Some people are likely fast metabolizers who might clear it more quickly."

How Do Labs Test for Cannabis?

Labs can test for the presence of cannabis in several different ways, including urine, blood, saliva, and hair. The most common testing methods include:



urine in bottle and cannabis
Some cannabis consumers refuse jobs that involve drug testing.

Urine testing is the most common drug test. In a urine test, laboratories are testing for the presence of THC metabolites.

Metabolites are derivatives of THC. The presence of THC metabolites indicates that the body processed the compound.

Specifically, laboratories are testing for the presence of a compound called THC-COOH.

For most urine tests, the presence of more than 50 nanograms of THC-COOH per milliliter of urine will trigger a positive test result.

After the 50 nanogram limit is triggered, a laboratory may test the sample again with a smaller detection point.

The second detection limit is typically 15 nanograms per milliliter of urine.



Blood testing for cannabis metabolites is not as frequent as urine testing.

However, blood tests are sometimes used by police officers after roadside stops to determine whether or not a person is impaired.

Testing with more than five nanograms of THC per milliliter of blood will cause you to fail a test.

Unfortunately, THC metabolites can be detected in blood for two to seven days after smoking for regular and chronic consumers. The presence of THC in the blood, however, is not an indication of impairment.

For single-use consumers, the detection time is around 12 to 24 hours.

During this time, a person may not be impaired in any way even though THC metabolites are present in the blood.


cannabis leaf in red hair
Have you ever submitted to a hair test?

Hair testing is perhaps the least common method of drug analysis. Cannabis metabolites can be detectable in hair tests for months after consuming.

Most hair tests, however, feature a 90-day detection window. The length of the taken hair sample is what determines the duration of the detection window.

Hair samples are collected close to the follicle root, and a small segment of the hair is selected. Usually, the hair sample is around an inch and a half long.

Since most hair grows at a constant rate, the average hair sample will look for the presence of cannabis use over the preceding three months.


How to Detox Cannabis from your System

There are numerous detox pills, drinks, and products out there that claim to rid THC from the body.

Be warned, however. Dr. Tishler has a few words of wisdom to share about these quick-fix remedies.

"I would avoid [detox remedies] like the plague," he exclaims. "The only safe way is to stop using cannabis and let nature take its course."

"There are no known detox methods that are proven and safe," he continues. "There are many [products] available on the market about which we have no idea what's in them or how they supposedly work."

Most detox products contain high doses of vitamins and herbs, including b-vitamins, creatine, and so-called "purifying herbs" mixed into a "proprietary blend."

These drinks can also sell for top dollar, sometimes reaching between $30 and $60 for a single product.

These detox methods are highly unlikely to work.

Many of them contain compounds that alter the color of urine (like riboflavin).

Others increase the amount of creatinine in your urine, with the assumption that a consumer will drink several liters of water to dilute their sample before a test.

Unfortunately, this last-ditch effort is often futile. There is no way to detox THC from your body quickly, especially among heavy consumers.

Those that are concerned about detoxing from cannabis may want to consider the following:

Eat a High Fiber Diet

high fiber diet
Diet is everything.

Trace amounts of cannabis metabolites can be present in urine. Most metabolites, however, are excreted via stool.

Eating foods high in fiber before a drug test may help remove cannabis compounds from the body.

Fruits high in pectin, like pears, apples, and citrus fruits, might be especially beneficial.

This soluble fiber binds with bile in the small intestine and carries lipids out through the stool.


Exercising the day of a workplace drug test may not be the wisest idea.  But, getting some extra exercise earlier in the week may help you burn fat and, therefore, clear cannabis metabolites from your system.

Activity and exercise burn fat, which then releases stored cannabis metabolites back into the bloodstream. From there, these metabolites can be removed from the body over the day.

Stay Adequately Hydrated


woman drinking water
Are you keeping hydrated generally?

Staying hydrated is another wise idea before a urinalysis or blood screening.

Drinking too much water, however, can dilute urine before a screening, rendering it inaccurate. Staying hydrated, but not too hydrated, will ensure that you're eliminating THC metabolites as quickly as the body is naturally able.

When trying to eliminate THC from the body, go back to the basics.

Eating well, getting ample exercise, and drinking plenty of water are some of your best bets for a safe and clean drug test.

However, while cleaning up your diet and lifestyle may help immensely, it is still possible to fail a test if you have been consuming cannabis.


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