How Long Does Marijuana Stay In Your System?

Mar 26th 2020

While marijuana remains illegal on the federal level, it is increasingly legal on the state level. Whether a state permits recreational marijuana use or cannabis use is restricted to medical purposes, more people are using the drug than ever before. Even if recreational marijuana is legal in a state, that does not prevent an employer from firing a worker found with cannabis in their system. While the marijuana high may last from one to several hours, depending on the amount and type of consumption, evidence of marijuana use stays in the body for far longer.

Whether you are an employer drug screening your workers, a parent concerned about their child and seeking an at-home drug test, or someone anticipating a job interview in which a drug test is necessary, you want a reputable drug detector method. Before undertaking cannabis testing for any purpose, it is essential to know how long marijuana remains traceable in the body.


The psychoactive ingredient causing the marijuana high is tetrahydrocannabinol, usually referred to as THC. A certain amount of fat-soluble THC is stored temporarily in fatty tissues and bodily organs, but it is eventually broken down by the liver, where it breaks down into metabolites. It is the metabolites which drug tests seek out. While THC is eventually excreted via urine and feces, the metabolites remain in the body for a longer period.

Frequency of Use and Dosage

How long marijuana stays in the system depends on several factors. The first is the frequency of use. The occasional marijuana user may no longer have detectable levels of THC in their system after five to ten days. However, the frequent user might have to forego cannabis for two weeks or more for a drug screening test to read negative. Very heavy users may still have detectable levels of THC in their systems as much as three months after giving up the drug.

The other factor determining how long marijuana may stay in the system is the dosage. More marijuana and more potent cannabis stays in the body longer than smaller, milder amounts.

Consuming edible forms of cannabis rather than smoking or vaping marijuana may also mean metabolites are detectable for a longer-term. Other factors affecting how long metabolites stay in the system include:

  • Body mass index –Those with more fat may find THC, binding to fat cells, will stay in the body longer.
  • Test sensitivity – All over the counter drug tests are not created equal. Much depends on the sensitivity of the test. A less sensitive drug test may not detect marijuana as well as a more sensitive test.

Blood vs. Urine Testing

marijuana urine drug testMarijuana does not stay in the bloodstream for a long time, so blood testing is of little value. While blood testing for cannabis is sometimes used by police departments after car accidents, blood testing for marijuana will not show intoxication levels, unlike blood testing for alcohol consumption.

Employers are more likely to use urine testing on a regular basis to detect marijuana-using workers. According to the renowned Mayo Clinic, occasional marijuana users, defined as up to thrice weekly, can expect urine samples to test positive for metabolites for three days after the last use. Moderate users, defined as four times weekly, can expect urine samples to test positive for up to seven days after the last use. Daily users may anticipate positive results from urine tests for 15 days after the last use, and heavy users, those who ingest marijuana several times daily, must wait at least 30 days after the last use for a urine test to possibly come up negative. As noted, metabolites can stay in the system of a heavy user for a very long time, so it is hard to predict when an individual may have a clean test. For best results, refrain from marijuana use for at least three months before urine testing.

Saliva Testing

saliva drug test for Marijuana While a urine drug test is the most common method used for marijuana detection, saliva testing is another alternative. Occasional users may have positive results after saliva testing for up to three days after the last use, while for daily users a positive result may turn up a month after the last cannabis smoke, vape or edible.

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