Tetrahydrocannabinol (THC)

Yikes! You?ve just landed your dream job and as you?re scanning over the offer and the new-hire packet, you see that you must submit to a drug test. Suddenly, the anxiety kicks in. You wonder when was the last time you smoked cannabis? Will the THC show up on the drug test? Exactly how long does it stay in your system? While it can vary, there are some averages.

First things first. There are some common averages for the half-life of THC, but many things are dependent upon the individual taking the test. Things like metabolism, diet, exercise, and body composition can affect how long THC stays in a person?s system, the ingestion method matters too, whether you are using dry herb vapes or just smoking marijuana. It can also depend on what exactly is being screened for the presence of THC ? blood, hair, saliva, sweat, or urine. It also depends on how often you partake. One time or scarce users find that the drug does not stay in their system as long as chronic users, where THC builds up in fat cells.

What Exactly Is a Drug Test Looking For?

Regardless of whether it is a blood, urine, saliva, hair, or sweat test, all drug tests seeking out THC are actually looking for the metabolite THC-COOH. This is the enzyme that is produced when your liver breaks down THC. The most common cutoff, that is, a positive result, is 50ng/mL. However, some drug tests go as low as 15ng/mL or as high as 100ng/mL.

The Science-y Stuff

A 2005 review by the director of the Toxicology and Drug Monitoring Laboratory at the University of Missouri revealed that while detection times of longer than 30 days occur, they are not the norm. The director, Paul Cary, went further: He states ?it would be unlikely for a chronic user to produce a positive urine drug test result for longer than 10 days after the last smoking episode,? when speaking of the likelihood of a positive result at 50ng/mL for a frequent user. If you just tried cannabis for the first time, Cary states, ?It would be unusual for the detection of cannabinoids in urine to extend beyond 3-4 days following the smoking episode.?

The Different Kind of Drug Tests

All of this said, the differing kinds of tests can detect THC in your system for a varying number of days. For example, a hair test can probably detect THC for the longest amount of time, whereas a saliva or blood test can typically only detect it If it has been used in the last 24 hours.

Urine Test

This is one of the most common types of drug tests administered. While these numbers are only guidelines, they are the averages for how long that studies have shown THC can stay in your system.

  • Single use:up to 8 days
  • Frequent use:up to 15 days
  • Regular use:up to 30 days
  • Heavy use:up to 45-77 days


Saliva is the type of test used by some police jurisdictions while looking for drugged drivers, particularly in states where medical or recreational cannabis is legal. The good news is that on the low end, THC only stays in your saliva for 24 hours. That can increase with use, however.

  • Single use:up to 24 hours
  • Frequent use:up to 72 hours
  • Chronic, heavy use:up to one week


The bad news is that a hair test has the longest detection method. The good news is that hair tests are probably the most infrequently used. While cannabis metabolites do not show up until 7 days after consumption, they can remain in hair for at least 90 days.


Like with hair testing, THC testing with blood is not at all that common. THC metabolites do not linger in the bloodstream for long.

  • Single use:up to 24 hours
  • Frequent use:up to 3 days
  • Regular use:up to 1 week

While these time frames can vary depending on the individual, they are a rough guide that can let you know how long you can expect to be sweating a drug test, if one pops up.

Michael Jacobs
Author Michael is a marketing and creative content specialist at with primary focus on customer satisfaction. Technology and fitness combined healthy lifestyle obsession are his main talking points.

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