How Long Does Marijuana Stay in your System?

Reviewed by Dr. Michael McGee - Board Certified Physician in General Psychiatry, Addiction Psychiatry, and Psychosomatic Medicine.

The short answer is it will vary depending on how it is tested (urine, blood, hair, etc) and how often you consume on a daily basis.

Last updated: March 15, 2019
A massive weed bud

How long does marijuana stay in your blood?

Whenever you consume marijuana (either by smoking, eating, or drinking), the active components enter your bloodstream first. Essentially, your bloodstream is where the party kicks off before the chemicals reach your organs and brain.

THC will remain in your blood for around one to two days after a single use.

THC is stored in fat. If you are a habitual user, THC will accumulate in your body. This means that you can detect THC for as long as 30-60 days after your last use if you used heavily for a long time.

THC can also be found in your urine

Testing urine is the most convenient and common way that employers will test for marijuana.

While you might think they’re testing for weed, they’re actually only testing for THC. This is because the body rapidly metabolizes the other cannabinoids in marijuana. THC, on the other hand, is fat-soluble, meaning that it will bond with fatty tissue in your body and stick around for much longer.

The duration that THC will remain in your urine largely depends on the amount that you consume on a regular basis. There isn’t any magic number, but based on scientific studies, the numbers break down as the following:

  • 5 to 8 days for one-time use
  • 11 to 18 days for two to four times a week
  • 33-48 days for five to six times a week
  • 50-65 days for everyday usage

THC is also present in your saliva

Saliva and blood have relatively similar durations regarding the amount of time THC is present. In fact, mouth swab and blood tests for THC are relatively the same because of the similar duration.

So how does THC get into your saliva?

When you smoke marijuana, the THC will coat the inside of your mouth and is absorbed into your saliva glands. The same is true for edibles, but exposure to saliva is more limited. Your body also excretes THC from your blood into your saliva glands. There are ways to speed up the process to wash your saliva of THC such as brushing your teeth, eating fatty foods, and drinking lots of water.

Even so, studies show that THC will stay present in saliva for a day or two after a single use of marijuana. If you smoke a lot or ingest more potent marijuana, it could stay in your saliva for up to a week or more after.

Your hair is a THC time capsule

The evidence that you consumed marijuana will stay the longest in your hair follicles. It might sound crazy, but you can detect cannabis use in hair for years depending on how fast your hair grows and how often you trim it.

Even so, in most common tests, the evidence shows for around 90 days. Some might think that tests only check the tips of the hair, but for the test to work optimally, a 1.5-inch sample of hair is needed.

The hair on your head grows at an average rate of half an inch per month, so 1.5 inches is equal to three months of history. Body hair doesn’t grow as fast, and will typically show cannabis usage back even further.

Keep in mind that hair tests are meant more to check for habitual use of marijuana, and if you only smoke once or on occasion, the test shouldn’t be able to detect any usage.

Flushing it out of your system

There are tons of “tips and tricks” floating around the Internet that claim to help users flush the presence of THC and marijuana out of their system faster. There are also products that you can buy in smoke shops that claim to beat the test.

Typical advice includes drinking cranberry juice, lots of water, increasing your exercise, taking particular vitamins, and more. The list goes on and on, and the truth is there isn’t one way that you can “flush” marijuana out of your system. The only thing that is proven to work time and time again to eliminate the traces of marijuana from the body is time.

It won’t stay in your system forever. Depending on how frequently you consume marijuana your time duration may vary. With that in mind, if you smoke the night before a drug test, there isn’t anything you can do to get it out of your system faster.


Despite having mental/physical effects that may last a relatively short period, traces of marijuana will stay in your system for much longer than some other drugs.

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