Medically Reviewed by
Jason Crawford

Article Last Updated on January 3, 2023

Marijuana use has increased along with legalization laws around the world as cannabis users consume both recreational and medical marijuana for conditions like chronic pain, loss of appetite, or mental health disorders. 

While we’ve previously covered subjects like how long does smoking weed once stay in the body as well as whether you can pass a drug test if you’ve consumed marijuana one week ago, in this article, we’ll elaborate on another subject in a similar vein.

Our focus in the next few paragraphs will be to give you more information about how cannabinoids travel in the body, as well as where THC is stored. So, read on.

How Are Cannabinoids Absorbed From the Cannabis Plant in the Human Body?

In order to learn how THC is stored in the human body, the first thing you need to understand is how cannabis affects the body.

For cannabis to have its psychoactive effects, it first needs to be decarboxylated, meaning that the carboxyl group from the tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) is removed, and the acids are transformed into tetrahydrocannabinol (THC) and cannabidiol (CBD).

Right after cannabis is consumed, cannabinoid levels in the body increase and the same goes for THC, CBD, as well as other cannabinoids like CBN and CBG. The cannabinoids give the psychoactive effects, while the metabolites are what’s left behind after the body processes the cannabis.

Cannabis and Its Metabolites

Metabolites are a natural byproduct of THC and other cannabinoids. After the consumption of cannabis, the cannabinoids are metabolized into more than 80 metabolites by the metabolic enzymes in the liver. 

The most important metabolites are 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol) and THC-COOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol). They’re precisely the metabolites that will show on drug tests, although the main metabolite that drug screenings look for is THC-COOH.

After the consumption of cannabis, peak THC concentration happens after 10 minutes, while the levels of THC-COOH peak at around 80 minutes. However, peak levels of THC can vary depending on cannabis consumption methods (whether cannabis was consumed by smoking or ingestion). (Huestis et al, 1992)

THC to Body Fat Distribution

As it was previously stated, the active ingredients from the cannabis plant are absorbed into the bloodstream, and the metabolites are stored in the fatty tissues. This is a direct result of the cannabinoids being lipid-soluble, not water-soluble, hence THC, CBD, and other cannabinoids linger in body fat and get detected as metabolites in various drug tests. Since metabolites are stored in the fat tissues in the body, marijuana has a long detection time.

THC and the Endocannabinoid System

The cannabinoid receptors in the body are responsible for the psychoactive effects of delta-9-tetrahydrocannabinol (Δ9-THC) and the effects of marijuana on our bodies. The presence of THC gives users the effects of a pleasurable “high,” and it’s all because of our endocannabinoid system (ECS).

The ECS consists of cannabinoid receptors CB1 and CB2 that get affected once THC enters our system and they’re responsible for the effects of cannabis on marijuana users. The cannabinoids affect different receptors as a result of cannabis use, and the effects range from euphoria and relaxation to anxiety, and maybe even psychosis.

How Long Does THC Stay in Your System?

As it was previously stated, THC metabolites are what lingers in the fat cells and they get detected on drug tests and toxicology reports. How long THC stays in the body depends on the half-life of marijuana, and whether or not you test positive will depend on a few reasons.

Frequency of Cannabis Use

How often you use cannabis, and when you last used it will determine the half-life of cannabis in your body. Chronic users retain cannabis metabolites for longer compared to occasional users.

Metabolism and Body Fat Percentage

Higher levels of body fat and a higher BMI will result in users storing more cannabinoids and metabolites for a longer time.

The Strain and Dosage of Cannabis

High THC strains will result in higher levels of THC.

What Are the Types of Drug Tests That Determine THC Presence in the Body?

Metabolites, unlike cannabinoids, don’t cause impairment to users, although they can be useful for figuring out if someone has been using cannabis. Drug tests aim to look for cannabis metabolites that are stored in the fatty tissues inside the body. As more time passes, metabolites get eliminated through feces and urine, so it’s important to know what the window of detection for drug tests is.

Urine Test

Urinalysis is one of the most common testing methods when it comes to cannabis drug testing. When testing the urine sample for cannabis presence, drug tests look for the immunoassays with antibodies that are sensitive to THC-COOH. According to a 2017 study conducted by the Mayo Clinic, the amount of THC metabolites in the urine is detectable for only 72 hours.

The urinary excretion half-life depends on how often marijuana users smoke weed. Heavy smokers will test positive for a longer time compared to occasional users. (Johansson et al, 1989)

Blood Test

Blood tests are more invasive compared to urine tests and they’re another testing method for the presence of cannabis metabolites in the body. THC remains in the blood from 4 hours up to 24 hours after consuming weed for occasional users, while frequent users can test positive for up to about a week.

Saliva Test

This type of testing is one of the newest and less invasive ways of drug testing. With a saliva test, cannabis users can test positive for weed for up to 72 hours after using cannabis.

Hair Test

Hair follicle testing provides the longest detection period for weed and other drugs, and it’s slowly becoming a very common way to test for drug use. Users can test positive for up to three months after consuming weed.

Cannabis Detox

In order to evade a positive drug test, cannabis users turn to detoxing their bodies and flushing out THC from their system.

Since THC metabolites build up in the fatty tissues, some cannabis users turn to exercise in order to help their body flush out weed faster. Others may mask their urine samples, or even use detox drinks. And some even do a niacin flush as a way to rid their body of cannabis metabolites. If you’d like to learn how long it takes for niacin to flush THC from the body, read our guide.

Still, even though these methods may work for some marijuana users, more studies need to be done that look into these detoxing methods.

The 411 on Where THC Is Stored in the Body

As a result of cannabis being fat-soluble, the metabolites of cannabis 11-OH-THC and THC-COOH will remain in the body long after the initial psychoactive effects of cannabis pass. Remember, cannabis is stored in the fat cells in the body where it can be detected for up to three months.

The frequency of use, how fast the body metabolizes cannabis, as well as the strain and dosage of cannabis, will affect how long marijuana stays in the body. To avoid getting a positive result, keep in mind that people with higher metabolic rates that consume cannabis occasionally are likely to metabolize it faster, so make sure you give your body enough time to detox before you take a drug test.

Additional Sources

Huestis, M. A., Henningfield, J. E., & Cone, E. J. (1992). Blood cannabinoids. I. Absorption of THC and formation of 11-OH-THC and THCCOOH during and after smoking marijuana. Journal of analytical toxicology, 16(5), 276–282. https://doi.org/10.1093/jat/16.5.276

Johansson, E., & Halldin, M. M. (1989). Urinary excretion half-life of delta 1-tetrahydrocannabinol-7-oic acid in heavy marijuana users after smoking. Journal of analytical toxicology, 13(4), 218–223. https://doi.org/10.1093/jat/13.4.218

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.