How Long Does THC Stay in Your System?


If you live in a state where the use of medical and recreational cannabis is controlled, or if you’re planning to work for a particularly conservative employer, you’ve probably asked: “how long does THC stay in your system?”. Unfortunately, there are no quick answers to this question.

Tetrahydrocannabinol or THC is the active chemical in cannabis that gives people a “high”, and it’s usually the substance drug tests specifically test for if someone wants to specifically screen for marijuana use. Compared to other substances like alcohol, THC is actually quite persistent in the body, and it can be detected in your blood, saliva, or urine up to several weeks after your last intake. In the case of hair follicles, it may be present for up to three months or more.

This period is often vague because THC persistence in urine is dependent on a number of factors. Frequency of consumption, dosage size, body fat, and genetics are just some of the factors that determine how long THC will be detectable in your system.

Of course, the sensitivity of the drug test is also a major factor that shouldn’t be overlooked, as they may show that there is no THC in your system, when in fact, the THC is still there, albeit in levels too low to detect.

Here are some of the factors that can lengthen or shorten the persistence of THC in your system:


Some people have faster metabolic rates that allow them to break down THC in their system relatively quickly, sometimes in just a matter of days.


It may very well be that a person’s system is faster or slower at breaking down THC specifically.

Body fat

THC easily binds to body fat. The more body fat a person has, the more likely THC is to persist in their system.

Biological sex

Females tend to have both a slower metabolic rate and a higher body fat percentage. This means that females usually take longer to fully expel THC from their system.


The more dehydrated you are, the more concentrated THC becomes in your body, and the higher the concentration that would be found in a drug test. Being more hydrated reduces the relative concentration in your blood, saliva, or urine, but is unlikely to reduce the effectivity of modern drug tests.

As mentioned earlier, THC binds itself to your body fat. Exercise can release stored THC into your bloodstream, which can increase the chance of a positive result in a blood test. Regular exercise may theoretically allow you to expel the “loose” THC faster, though this is not proven.

Dosage and frequency

This is the most important factor in determining how long THC stays in your system. An occasional user of low dosage THC will not build up that much THC in their body fat, and levels may be undetectable in blood, urine, and saliva in a few days, provided they have a favorable body fat percentage and metabolism.

On the other hand, a regular user will eventually build up a store of THC in their fat cells. IF they have a high percentage of body fat and if they have a slow metabolism, chances are THC will remain detectable for several weeks to a few months after their last intake.


Unfortunately, the answer to “how long does THC stay in your system?” has no one-size-fits-all answer. On the other hand, there are also home test available to help you determine if THC is in your system in detectable levels. Taking these tests beforehand may allow you to track your progress in metabolizing THC and give you confidence when you take the drug test for employment.

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