By Luke Sumpter Reviewed by: Gloria Payá

Use this guide to help eliminate THC from your system!

Good news! You just got your dream job. But, your new career comes with a catch—a zero tolerance drug policy. Do you give up weed? We know that might be intolerable or even impossible. There are many reasons why people choose to use cannabis, and we don't judge; we just puff, puff, pass.

So, you make your best choice and continue to partake. But, you suddenly find yourself facing a drug test. Eep! What to do!? Read on to find out how to get THC out of your system.

How Long Does Cannabis Stay In Your System?

The length of time cannabis stays in your system is affected by your unique biology and habits.

Cannabis is usually detectable in fluids like urine and saliva from 1–30 days after last use. It may be detectable in hair for months.

THC is metabolised in the liver, where it gets broken down into over 80 metabolites. Eventually, THC and its metabolites are excreted, leaving your system. However, many of these compounds linger in your system longer than THC itself. Most drug tests are designed to detect certain metabolites, like tetrahydrocannabinol carboxylic acid (THC-COOH).

THC Metabolism and Storage

Factors That Affect How Quickly You Metabolise THC

Strength of the cannabis you use Your individual genetics
How much/how frequently you consume cannabis How much body fat you have and your metabolic rate
Sensitivity and type of drug test used How often or hard you exercise
Your level of hydration
  • Strenght of the Cannabis You Use

Cannabis strains are becoming stronger and stronger. These days, cultivars can clock in with a THC content of over 30%. These varieties introduce much higher levels of THC into your bloodstream and bodily tissues. As well as completely knocking your socks off, they’ll leave THC and its metabolites lingering in your body for longer.

  • Your Genetics

Your individual genetics can play a large role in how quickly your body breaks down cannabinoids such as THC. For example, cytochrome P450 enzymes in the liver are involved in the breakdown of THC; however, the variability in our genetics means that these enzymes work at slightly different rates in different people. Some people are able to metabolise THC faster than others.

  • Dosage And Frequency Of Use

The amount (and frequency) of cannabis you regularly consume is perhaps the biggest factor. This one really is a no-brainer: The more cannabis you consume, the more metabolites there are knocking around in your body. Cannabis taken orally, like edibles, may also linger in your system longer than smoking.

Consumption rules apply to both individual doses and long-term habits. Two grams of weed will take longer to leave your system than one. Weed that's more potent will take more time to clear out too. If you're an occasional user, your system will eliminate THC faster. So, take note! If you're a chronic user of cannabis, you may need extra time to abstain before you can pass a drug test.

  • Body Fat And Overall Metabolic Rate

THC is detectable for longer in chronic users because THC metabolites get stored in fat cells (they are lipid soluble). A person with less body fat will store fewer of these molecules, and a person with more body fat will store more. That's why sex can sometimes be a factor as well. Females tend to have more body fat than males, so women may metabolise cannabinoids more slowly.

A person's overall metabolic rate also plays a large role. Some people can burn calories just by sitting around, while others struggle to lose weight even with an active lifestyle. Those with a faster metabolism will process and eliminate cannabinoid metabolites more quickly. Just be aware, if you exercise heavily before a drug test, the fat you burn could release more THC metabolites into your system, causing a temporary spike.

  • Sensitivity Of The Drug Test

Different drug tests—urine, hair, saliva, blood—have different detection windows. Many, like hair and urine screenings, measure the THC metabolite THC-COOH, while blood tests measure levels of THC itself. Of all the standard testing methods, urine testing is by far the most common[1]. If you're being drug tested at work, it's almost always going to be a urine test.

Test sensitivity refers to the cutoff concentration of THC or its metabolites, above which a test is considered positive. The cutoff for most cannabis urine tests is 50ng/ml of THC-COOH. However, it is possible for the cutoff to be set as low as 15ng/ml. The more sensitive the test, the longer the detection window is.

How Long Does Weed Stay in the System of an Athlete?

Athletes are constantly stimulating their metabolism when training and competing. But does this offer an advantage when it comes to ridding your system of THC? It turns out things are fairly nuanced.

  • Exercise

Athletes are almost always in fantastic shape. High levels of exercise during constant training help them keep off the pounds and help maintain low levels of body fat. Cannabinoids such as THC are lipophilic, meaning they are dissolvable in fat—hence why people use butter or coconut oil when cooking with weed.

The same applies inside the human body. THC stays stored away in fat cells for significant periods of time. Exercise promotes the breakdown of fat for energy, which causes THC to release back into the blood. Exercising can help to remove THC from the body a few weeks before a test.

If you use cannabis a matter of days before a test, exercising immediately beforehand in an attempt to reduce your chances of a positive result could backfire!

It makes sense to abstain from cannabis for a couple of weeks before a drug test if you’re lucky enough to know the date.

  • Hydration

Athletes are no strangers to hydration. Fluids and electrolytes help to improve muscle function, enhance circulation, and regulate blood pressure. But hydration can also play a role in dodging a positive result during a drug test. If you don’t manage to abstain from cannabis and likely have traces of THC in your blood, drinking plenty of fluids can help to dilute the cannabinoid and reduce the chances of pinging positive.

Dilute your urine

Drug Tests And Detection Times

According to available research, these are the most common detection windows for different drug tests. Keep in mind, the timeline varies according to your unique physiology and personal habits.

  • Urine Testing

Cannabis and its metabolites are detectable in urine[2] for varying amounts of time after last use, depending on how frequent of a user you are:

Occasional user (one to three times per week): 3 days
Moderate user (four times per week): 5–7 days
Chronic user (daily): 10–15 days
- Heavy chronic user (multiple times per day): 30+ days

This is, of course, assuming the test sensitivity cutoff is a standard 50ng/ml.

Urine Testing
  • Saliva Testing

Roadside saliva tests may be used to detect impaired driving in some jurisdictions where cannabis is legal. According to a scientific review[3], cannabis can typically be detected in saliva for:

Occasional users: 1–3 days
Chronic users: up to 29 days

Saliva Testing

  • Blood Testing

Blood testing is relatively costly and invasive, making it less common than other testing methods. However, blood tests may be used in some clinical or emergency settings. Unlike urine tests, which detect metabolites, blood tests typically look for the presence of THC itself. THC is almost instantly detectable in the blood upon inhaling cannabis, making blood tests ideal for determining recent drug use.

Research shows[4] that cannabis remains detectable in blood for 1–2 days. However, in certain cases it has been detected up to 25 days later. Heavy, chronic use of cannabis can increase the length of the detection window.

Blood Testing
  • Hair Testing

Following consumption of cannabis, THC reaches the hair follicles through small blood vessels. Trace amounts can be detected in hair for up to 90 days, as confirmed by a 2015 study[5]. Typically, a 4cm section of hair taken from near the scalp indicates cannabis use over a three month period (hair grows at an approximate rate of 1.2–1.5cm per month).

Hair Testing

If you're required to take a hair follicle drug test, around 100 hairs will be taken from near the crown of your head. Washing, dyeing, or styling your hair with products will have no effect on the accuracy of the test.

How To Get Thc Out Of Your System

So, you've got a drug test coming up and you're feeling uneasy. Don't get defeated! Here's how you can try and beat it.

1. Stop Consuming Cannabis

This may seem obvious, but the first thing you should do if you have a drug test coming up is stop using weed. The aim here is to purge any trace of THC or its metabolites as thoroughly as possible. The longer you cease smoking beforehand, the more likely you are to pass the test. Depending on the type of test and your smoking habits, you may need to take a longer break to fully flush your system.

Stop Consuming Cannabis

2. Drink Lots Of Water

Speaking of flushing your system, there's nothing better than good ol' H₂O. Of course, drinking water is most effective for passing urine tests. Luckily, that's the most common type of test.

To help cleanse your system, pee as much as you can 24–48 hours before your test. Keep hydrating on the day of your drug test. The goal is to dilute your urine, making it harder to detect any residual metabolites.

Just don't overdo it. Drinking too much water will result in an obviously diluted sample, potentially leading to a retest or increased suspicion. You need to drink plenty of water, but not so much that it becomes obvious. This is indeed a balancing act.

Drink Lots Of Water

3. Take Zinc

A 2011 study[6] found that zinc is an effective urinary adulterant, with the potential to produce a false negative test result. Research suggests that oral consumption of zinc supplements after light cannabis use could interfere with detection of THC metabolites in urine for between 12 and 18 hours.

Zinc supplements are widely available over the counter in pharmacies and health food shops. So, if a drug test gets sprung on you or you need some extra assurance, you might want to swing by the vitamin aisle. Just make sure to check with your doctor or pharmacist first if you take any regular medications.

Take Zinc

4. Detox Drinks

If you want to kick it up a notch from water, try a detox drink. Detox drinks promote hydration, and may be beneficial to the proper functioning of detoxing organs in the long term.

Consumer detox products can be quite expensive. If you don't have the cash, focus on simple detox drinks you can make at home, like coffee or cranberry juice.

Detox Drinks

5. Activated Charcoal

Another method to prepare your body for a drug test is activated charcoal. Charcoal is often used to medically manage overdoses; it binds to different substances and helps the body eliminate them. That's because charcoal molecules have a negative electrical charge; they bind with positively charged molecules in different drugs, trapping them.

The binding process works with THC metabolites. THC metabolites circulate many times through your system via a process known as "enterohepatic recirculation". They move from blood to liver to bile and into the intestines, before being reabsorbed back into the bloodstream. The cycle then repeats, with a portion of the metabolites excreted as waste each time. Eventually, after many cycles, all metabolites are flushed from your system.

Activated Charcoal

Research[7] shows that activated charcoal binds to metabolites like THC-COOH and THC-COO-glucuronide, preventing their reabsorption into the bloodstream and speeding up their elimination. That means charcoal could help you pass a drug test faster.

How To Ingest Activated Charcoal

So, what's the best way to take activated charcoal? Thanks to its purifying properties, charcoal has gained popularity as an addition to cosmetics, health products, and even food. The simplest way to take it is via capsules. But, let's be honest, it's more fun to do a little baking! The recipe below for charcoal bread results in a unique, black loaf that looks badass and still tastes great.

Please note that you should be careful when ingesting activated charcoal—it could interfere with absorption of medications and vitamins. If you have concerns or take regular meds, check with your doctor or pharmacist before trying it.

Charcoal Bread Recipe

This gothic dough will turn any sandwich into a conversation piece.


240g plain flour
7g dried yeast
50g caster sugar
½ tsp. salt
2 tsp. activated charcoal powder
140ml warm water
30g butter


Large bowl
Cutting board/breadboard
Bread tin
Kitchen towel
Roasting tray
Wooden spoon

External Resources:
  3. Current Knowledge on Cannabinoids in Oral Fluid
  4. Detection times of drugs of abuse in blood, urine, and oral fluid. | Semantic Scholar
  5. Hair Drug Testing Results and Self-reported Drug Use among Primary Care Patients with Moderate-risk Illicit Drug Use
  6. Zinc Reduces the Detection of Cocaine, Methamphetamine, and THC by ELISA Urine Testing - PubMed
  7. An in vitro experiment on the interaction of charcoal or wheat bran with 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol and its glucuronide | SpringerLink
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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