As laws change, talking about marijuana use is slowly becoming more common. Some people are assessing its medicinal value, while others are looking for ways to flush it out of their system because of drug testing or a simple desire to get toxins out of their systems.
But what exactly are they flushing out, and how long would it take to happen naturally?
What marijuana leaves behind

When you smoke or consume marijuana, you can feel profound and immediate effects. But even once those effects are gone, marijuana metabolites remain. This means that chemical remnants of the plant are still present within your body.
These remnants are called cannabinoids.
What drug tests look for
Drug tests look for the presence of the cannabinoid tetrahydrocannabinol (THC) and its metabolites. Generally, urine is tested, both because it’s easiest to collect and because THC remains detectable for a longer period of time in urine than elsewhere.
The main metabolite these drug screenings look for is called THC-COOH. This substance is stored in your body fat.
“Compared to other drugs, marijuana has the longest detection time, up to months, because the detectable chemicals stay in the body’s fat cells,” explained Nicolas Rossetti, manager of clinical services of Mobile Health, an occupational health center that conducts about 200,000 drug tests in New York City each year.
How detox remedies work
The vast majority of marijuana detoxes seek to flush the body of any detectable THC. These kits include capsules, chewable tablets, drinks, shampoos, and even mouthwashes to help you pass a saliva test.
However, if a drug test is your concern, detoxes can have additional effects that can make your urine sample look suspicious.
“Cleanses and teas can lower THC levels through their diuretic properties. They make individuals urinate a lot, which technically washes out the kidneys,” said Rossetti.
“This flushing of the kidneys can lower the specific gravity or density of the urine,” he added, “and a low specific gravity indicates contamination on the test, and the specimen could be discounted.”
Also, cleanses and teas may alter the amount of creatinine in the urine, another measure that drug tests look at. Abnormal creatinine levels can indicate contamination, according to Rossetti. This means the tester could assume that you attempted to cheat on your drug test.
While that doesn’t mean a positive test, it does mean the sample is unacceptable, and you’ll likely have to take the test again.
How long THC sticks around

THC can be detected in your blood, urine, and even in your fat cells. The length of time THC remains detectable in the body depends on several factors, including:
- metabolism and eating habits
- exercise routine
- body fat percentage
- frequency and quantity of marijuana use
Because of all these factors, there is no single standard detection time. Some estimate it can stick around for anywhere from two days to several months.
Urine
Cannabinoid metabolites can remain detectable in urine even after long periods of abstinence. One study found traces of one metabolite, delta 1-THC, in urine as long as four weeks after use.
How Much Urine is Needed for a Drug Test?
The average amount of urine in milliliters needed for a drug test is 30 milliliters. This amount can vary, for example, tests done for employees of the U.S. Department of Transportation require 45 milliliters of urine for a test.
Is 14 Days Enough Time to Prepare for a Drug Test?
The amount of time needed to prepare for a drug test depends on a person’s metabolism, age, sex, weight, and most importantly, how much they consumed. For instance, if a highly concentrated THC product is consumed, it will likely remain in one’s system longer than a low-dosage THC product would. Furthermore, frequent marijuana users will take longer for THC to fully leave their system, possibly twice the amount of time depending on other factors.
How Will Water Fasting Affect a Urine Test?
While drinking water helps cleanse the body by increasing urination, it is not recommended to fast using water before taking a drug test. One reason is that water fasts could further dehydrate you. One 2016 study published in the journal Nutrients found about 20% to 30% of your daily water intake comes from the foods you eat.
Fat cells
THC builds up in fat tissue, and from there slowly spreads to the blood. According to a 2013 study, exercise can cause THC to be released from your fat stores and into your blood.
Blood
THC can remain detectable in your blood for as long as seven days, depending on how frequently you use marijuana. Someone who smokes marijuana daily will likely carry marijuana metabolites for longer than someone who smokes infrequently.
The takeaway
As of 2018, marijuana is legal for recreational use in the U.S. in these states: Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, Washington and Washington, D.C. Medical marijuana is approved in over 20 states.
But regardless of its legality, it’s important to remember that marijuana carries with it certain medical risks. Know the risks before you decide to use it or not.
How Does THC Move Through the Body?
You might have heard rumors that cannabis can stay in your system for days, weeks, or maybe even months, but the way THC travels and interacts with the body paints a slightly more complex picture.
If cannabis is smoked or vaporized, THC enters the bloodstream from the lungs and goes directly to the heart, where it is then pumped throughout the body to the two types of cannabinoid receptors found in the human body.
“THC travels in the blood to the CB1 receptors located in the brain and central nervous system, and the CB2 receptors located in the spleen and immune system,” said Itzhak Kurerk, Ph.D., CEO and co-founder of Cannformatics, a Northern California biotech company researching improvements to medical cannabis.
Every time the blood circulates throughout the body, a certain portion of THC passes through the liver. When THC is broken down in the liver, it forms at least 80 different metabolites, including 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THC-COOH), both of which are inactive forms of THC that remain in the body far longer than active THC. Some of these metabolites, such as THC-COOH, are stored in body fat and gradually eliminated from the body through urine and feces.
“Tests for cannabis consumption mainly detect a metabolite of THC found in urine,” Kurek explained. “This metabolite [THC-COOH] is a result of the detoxification process in the liver by cytochrome P450 enzymes and further oxidation.”
When cannabis is ingested in the form of an edible or capsule, THC enters the bloodstream through the walls of the stomach and intestine. THC will travel directly to the liver where a substantial amount is eliminated or metabolized before the cannabinoid receptors are activated. After that, the remaining THC and its corresponding metabolites are put into circulation by the heart, where they both reach the brain.
So, contrary to what some might think, most cannabis drug tests aren’t only specifically looking for THC, but also metabolites such as THC-COOH that are created as the cannabinoid is rapidly broken down in the body.
I have been clean for exactly a month and I smoked 2 blunts just for today. How long will it take to get clean? I’m 5’3 at 137 pounds and I recently started hitting the gym again. I go about 4-5 times a week. Please help. I don’t have an upcoming drug test but I do want to be on the safe side in case I have to test for nursing program.