Why Does THC Stay In Your System For 30 Days?

The compounds in Cannabis can take up to one month before they are eliminated from the urine. This is even longer than alcohol, cocaine and other drugs. So, if you’re hoping to have a clean urine test, you’ll be waiting for some time before it happens. Why does it take THC so long to clear out of your system?

What Are Cannabis Urine Tests Looking For?

First, it’s important to understand that urine tests for cannabis don’t measure the amount of tetrahydrocannabinol that’s in your system. The test only looks at the concentration of THC-COOH, a THC metabolite. The metabolites are proof that the body has broken THC down.

  • If you regularly consume cannabis, it can take up to a month before your last consumption for the body to expel all the metabolites.
  • If you use it intermittently, the metabolites are typically gone within two weeks of the last consumption.

A study from 1985 found that a habitual THC user had THC in their urine for up to 77 days. It also revealed that the average cannabis user could see a clean urine test after day 25.

A study sometime later noted that habitual cannabis users could have a clean urine test result after 27 days of the last consumption. Whatever the situation, it’s safe to say that 30 days after the last consumption tends to be the consensus that a clean urine test will be seen.

Of course, the average length the THC metabolites are detected will depend on how the compounds are tested. For example:

  • Blood tests – One to seven days (14 days for habitual users)
  • Fat – Multiple weeks
  • Hair – 90 days
  • Saliva – One to seven days
  • Urine – Up to 30 days

Your Body Fat Is The Culprit  

Surprisingly enough, you can blame your body fat for the long length of time. The fat stores the cannabis. After you ingest or inhale cannabis, the fatty tissue, such as your brain, soaks up the cannabis from the bloodstream and stores it. If you smoke a joint every now and then, the THC isn’t going to be detected after a week. But, if you regularly use cannabis, the fat has had a chance to soak up and store the cannabis.

How long detectable THC levels stay in the body depends on a multitude of factors:

  • BMI (body mass index)
  • Metabolism
  • Amount of cannabis consumed
  • How often you consume it
  • How strong the cannabis is
  • Kind of test being used

After the fat cells have soaked up the THC, the cannabinoid is released back into the body when the fat cells are used for fuel. Two separate human studies show that THC blood plasma levels were higher after workouts. What does this mean?

It means that after using THC, minute amounts of it release and re-release into the body creating the effects even after you’ve not ingested or inhaled it for some time. In one study, participants with higher BMIs had the highest amount of THC release after exercising. While this could be beneficial to some users, the THC the body releases is unlikely to show any prominent changes in cognitive abilities.

Of course, exercise is a natural way to experience a natural high!

Joint Stuff” (CC BY 2.0) by halseike

This post has been updated since its original publication in 2014.