Cannabis Science

How Long Does Marijuana Stay in Your System?

lighting a blunt

Marijuana, also known as weed or ganja, is a drug often tested for in drug tests. While your high may wear off in a couple of hours or so, tetrahydrocannabinol (THC), the compound tested for in drug tests, will still be present in your body for some time after. In order to determine how long marijuana will stay in your system, there are many factors to consider.

In addition to that, it is present in an array of bodily fluids for varying amounts of time. Let’s first examine how marijuana is broken down in the body in the first place.

How Is Marijuana Broken Down in the Body?

According to Dr.Emily Earlenbaugh, director of education for Mindful Cannabis Consulting, the liver primarily metabolizes the components of marijuana. The heart pumps blood to the liver. Then, the liver, which has an abundance of the enzymes to do the job, metabolizes THC into THC-COOH glucuronide.

THC is metabolized and turns into various compounds such as THC-COOH. Finally, it gets to water-soluble compound THC-COOH glucuronide. The final product is easier to excrete. See the process in the diagram from Cannigma:

THC metabolism diagram
(Chart on how THC is metabolized Source: Cannigma)

Drug tests typically try to detect specific concentrations of THC-COOH in the urine according to Marilyn A. Huestis in her research Human Cannabinoid Pharmacokinetics

Earlenbaugh said that the body clears out most of the THC in around 5 days: “Within an average of five days, 80-90% of THC and (mostly) its metabolites will have been excreted — more than 65% via feces and 20% via the urine”. She further went on to say that there would be some THC and its metabolites stored in tissues. For some marijuana users these stores release slowly over time and can be detected in drug tests.

What Factors Affect How Long Marijuana Stays In Your System?

According to Healthline, the following factors influence how long marijuana stays in your system:

  • How much you smoke or ingest marijuana
  • How often you use marijuana

Frequency You Smoke or Ingest Marijuana

Generally, the higher the dosage is the longer the drug will stay in your system. Medical News Today says there is little information about how much exactly you’d have to smoke for the THC to fail your drug test. The article went on to say that the drug tests are able to pick up very little THC. The amounts of THC used would of course vary for each blunt. 

How Often You Use Marijuana 

If you’re a frequent smoker, then you’re more likely to return a positive drug test even if you haven’t used it in a while.

According to Healthline, “For daily users, cannabis may be detectable for several months after last use. The longest-reported detection times are more than 90 days.”

Medical News Today, cited a study on detection times based on use and the study reported the following results:

  • The detection window for someone who smokes for the first time is 3 days.
  • For someone who uses three to four times a week, the detection window is 5-7 days
  • The detection window for someone who uses once or more per day is 30 days or longer. 

Other Factors 

According to a study found on the Drug Court Practitioner Fact Sheet, by Paul L. Cary, M.S, the metabolic rate affects the levels of THC in the body. Cary noted, “The higher the metabolic functions of the client; the faster cannabinoids are broken down; the shorter the detection window.”

American Addiction Centers says that the amount of THC in marijuana and level of hydration of the user determines how long marijuana will show up in the test. 

Medical News Today outlined the following factors not previously mentioned:

  • Fat– Due to the fact that marijuana can be stored in fat, people with greater fat content metabolize the drug at a slower rate than those with less fat content. 
  • Sex- Women generally metabolize marijuana at a slower rate than men because women typically have more body fat.
  • Hydration- Being adequately hydrated or overhydrated won’t do you any favors on the drug test. However, being severely dehydrated will mean that there could be a higher concentration of THC in the urine. 
  • Exercise- According to a very small study of 14 people, exercising right before a drug test increased the likelihood of a positive test. The conclusion is that exercising may cause fat cells to release THC thus increasing its concentration. People with a higher BMI had a higher concentration of THC.

How Long Does Marijuana Stay in Your Blood?

THC is found in the blood seconds after inhalation. It typically won’t be detected in a couple of days.

According to American Addiction Centers “Marijuana and its metabolites can show up on a blood test for up to 36 hours”.

Healthline cited a study that says marijuana stays in the blood for 1-2 days after use.  However, in some cases, marijuana can be detected up to 25 days after last use.

How Long Does Weed Stay in Your Urine?

The urine test is the most popular form of drug testing. According to Mayo Clinic:

  • Single-use users will have THC in their urine for up to 3 days.
  • Moderate users (4 days a week) will have THC in their urine for 5-7 days. 
  • Daily users will have THC in their urine for 10-15 days.
  • Chronic heavy smokers will have THC in their urine for more than 30 days. 

Several other sources have cited and echoed what Mayo Clinic reported. However, American Addiction Centers and Pharma Drug Test made the distinction between detection times when you smoked marijuana versus when it’s ingested. If marijuana is eaten, it would be detectable 1-5 days after consumption. 

How Long Does Marijuana Stay In Your Hair?

Marijuana, according to Healthline, reaches the hair through blood vessels and stays in hair for 90 days. Even though Medical News Today called the hair test the most sensitive test, there is a conflict surrounding whether or not it’s a good indicator of marijuana use.  

According to a study, hair doesn’t reliably measure THC in light users but could measure THC just fine in heavier users. The study concludes “Hair analysis can be used as a qualitative indicator of heavy (daily or near daily) cannabis consumption within the past 3 months. However, this approach is unable to reliably detect light cannabis consumption or determine the quantity of cannabis used by the individual.”

Another study doesn’t believe testing hair is an accurate way of finding out if someone has used marijuana. Technically, someone could get a false positive because of “transfer through cannabis consumers, via their hands, their sebum/sweat, or cannabis smoke.”

How Long Does Marijuana Stay in Your Saliva?

Marijuana metabolites, according to Healthline can be detected in the saliva if you’ve smoked or ingested marijuana. 

According to American Addiction Center “A person can test positive for weed for up to 34-48 hours after last use”.

Healthline cited a study that concluded that marijuana can be detected in the saliva, 1-3 days after last use for occasional users and 1 to 29 days after last use for chronic users. 

How Long Does Marijuana Stay in Your System Calculator

Way of Leaf has a marijuana calculator that can help give you a rough estimate given factors like age, weight, height and usage.

Can I Speed Up The Time It Takes to Breakdown?

No. According to Healthline, “once it’s entered your system, your body needs time to break it down. Exercising, eating healthy, and staying hydrated may help, but not drastically.”

Healthline also said that the advertised weed detox remedies don’t work reliably. 


How long does weed stay in your system? Marijuana stays in your system for varying lengths of time depending on several different factors. Its ability to be detected in drug tests also vary depending on the test. There is no reliable way of making it metabolize faster and so you’ll just have to let your body do its job and avoid smoking your bong for a while.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].