Medically Reviewed by
Jason Crawford

Article Last Updated on January 11, 2023

As you probably already know, cannabis has a very unique chemical structure and its active compounds interact with our bodies in a very unique way. However, the duration of the effects of weed is much shorter than the length of time the cannabinoids remain in the body before they’re eliminated. THC is one stubborn compound that will linger in the fat cells for the longest time which can be days, weeks, or even months. 

Normally, this wouldn’t be a problem, but if you’re a cannabis user and work somewhere where occasional drug testing is mandatory, the presence of THC can become a problem. Therefore, knowing how THC leaves the body can be useful information that can help you understand what happens when you consume weed and how to eliminate it. 

That’s why in this article, we talk about what THC does once it enters our system and how exactly it leaves the body.

What’s the Deal With THC?

THC (tetrahydrocannabinol) and CBD (cannabidiol) are the most prominent cannabinoids present in weed. THC is the psychoactive cannabinoid that produces feelings of intense relaxation and euphoria, also called “being high.” CBD is non-intoxicating and used primarily for medical purposes.

When we talk about the effects of weed and getting high and how long weed stays in the body, we primarily refer to THC rather than CBD. The sole reason for this is that THC is still federally illegal due to its intoxicating effects, which makes it a target for drug screens. The fact that it remains in the body for a prolonged period of time makes it easy to be detected.

What Happens With THC When You Consume Cannabis?

When you consume weed through inhalation (whether smoking or vaping), THC enters your bloodstream through your lungs in a matter of minutes and starts circulating throughout the body. It travels to various sites in the body, including the brain, which is when you start to feel the effects. 

As THC gets carried through the bloodstream, it reaches the liver where it gets metabolized into over 80 byproducts, also called metabolites. THC metabolites are what’s left after your liver has processed THC and they remain stored in the body even after the THC itself is eliminated. The most abundant THC metabolites are called THC-COOH and 11-OH-THC. The metabolites are what drug tests look for because their presence shows recent use of weed.

THC gets processed in a slightly different way when you consume edibles or capsules because it has to be digested first. It enters the bloodstream through the walls of the intestines and stomach, from where it gets taken directly to the liver to be broken down. 

What’s left of THC and its metabolites is then sent back to the bloodstream and carried to the brain. Remember, this is why ingesting weed has delayed effects, but they’re longer-lasting.

Why Is THC Detectable Long After Last Use?

THC and its metabolites (THC-COOH and 11-OH-THC) are lipid-soluble compounds, which means that they attach themselves to fat. For example, when you make edibles or cannabis tea, you have to include a fatty substance to bind with THC for it to be absorbed by the body. Otherwise, it won’t have any effect. 

Similarly, THC binds to the fat cells once in the body and the THC metabolites are also stored in the body fat. They make a temporary home there until they get gradually eliminated by the body after a certain amount of time, which depends entirely on the user.

How Long Does Marijuana Stay In Your System?

How long weed stays in your body depends on many things – frequency of use, the dosage, your individual metabolism, and your BMI are only some of the factors. For example, chronic users who consume weed daily will store THC for longer than infrequent users who only smoke a couple of times a week.

Also, the larger your doses are, the more THC byproducts you will accumulate. And if the strains you commonly use have high THC levels, it will also result in a larger amount of THC in your body.

Finally, your BMI also has a role in how long weed will stay in your body. It’s believed that individuals with a higher BMI, meaning a higher percentage of fat cells, will store more THC metabolites than users with lower BMI. There are exceptions, as some people’s metabolism rate is naturally higher, but this applies to the majority of users.

How Does THC Leave the Body?

We already established that the THC metabolites THC-COOH and 11-OH-THC get stored in the fatty tissues in the body, but you might be curious about how exactly they get eliminated. To answer that question, we first need to establish the difference between THC-COOH and 11-OH-THC.

11-OH-THC is the main active THC metabolite that’s formed as a byproduct in the liver. It’s an active metabolite because it produces psychoactive effects similar to THC, but it has a slower onset. It’s thought that this metabolite plays a role in the slow onset of edibles. 11-OH-THC is predominantly excreted in feces.

On the other hand, THC-COOH is the main secondary metabolite of THC. It gets formed when a certain amount of the active metabolite 11-OH-THC goes through a process of oxidation. THC-COOH is an inactive metabolite, which means that it doesn’t produce any effects. THC-COOH is the metabolite that hair and urine drug tests screen for, and it’s predominantly eliminated through urine.

Over time, both metabolites get re-released into the bloodstream and go through a biological process where they get transformed into water-soluble compounds to get more easily eliminated from the body through urine and feces.

Is Doing a Detox Before a Drug Test Effective?

Doing a detox for a certain period of time in order to prepare for an upcoming drug test may be the safest way to pass it. The benefit of doing a detox is that you will take a tolerance break after which your sensitivity to THC can restore. This may not make that much of a difference to infrequent users, but to heavy users, it will.

However, you should remember that drinking lots of fluids won’t be enough. Ideally, you should include exercise in order to release those metabolites from the fat cells and eliminate them a little faster. It is also not advisable to exercise for at least 24-48 hours prior to the test because your THC levels will be elevated as a result.

Eating clean can also help, as well as taking zinc supplements and activated charcoal. In general, the goal isn’t to clear THC from the body completely but to get it below detectable levels.

What Are the Detection Windows of Different Drug Tests?

By far, the most commonly used drug test by employers is the urine test. It’s non-invasive, fast, affordable, and accurate. However, depending on the employment field, other types of drug tests can also be used to assess recent or habitual marijuana use. All of them have different detection times, depending on the sensitivity of the test. 

There are different cutoff levels for each test that measure the concentration of THC and/or THC metabolites and any number at or above this level will show a positive result. To avoid false positives, the tests are checked twice before the final test results are submitted.

Blood tests and saliva tests have the shortest detection windows of 36-72 hours. This is because these tests screen for THC itself instead of its metabolites.

Urine tests and hair tests have the longest detection times because they look for the metabolite THC-COOH. Urine tests can detect drug use from 3 up to about 30 days, depending on the marijuana user’s weed habits, while hair tests can go back 90 days. This is because THC-COOH is embedded into the hair follicle as the hair grows.

Bottom Line – THC Takes a While to Be Eliminated 

THC stays in the body long after the effects of weed have subsided because its metabolites get stored in the fatty tissues of the body until they get gradually eliminated. There are two main THC metabolites that get eliminated through urine and feces over a prolonged period of time, depending on things such as dosage and frequency of use, as well as individual metabolism. 

Different types of drug tests have different detection windows and cutoff levels, with saliva and blood tests having the shortest detection time, while urine and hair tests the longest. The best and safest way to get rid of THC is to detox naturally by taking a break and exercising.

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.