How long does marijuana stay in the body?

Dear Alice,

How long does marijuana stay in the body?

Dear Reader,

Marijuana, weed, pot: these are all different names for the same drug that comes from the cannabis plant. The main psychoactive ingredient in cannabis is tetrahydrocannabinol (THC), which stimulates your brain to provide a euphoric, relaxed feeling known as a “high.” These effects usually peak in about 30 minutes and may wear off in one to three hours. However, long after the experience of getting high has passed, traces of marijuana and its byproducts may linger in the body. Unfortunately Reader, there’s no simple answer to your question because the amount of time that it stays in the body depends on a variety of factors.

Factors impacting marijuana how long marijuana stays in the body, also known as metabolization rates, include:

  • Dose: Dosage of THC can be difficult to quantify since not all marijuana is created equal and the amount of THC in a given quantity of cannabis isn't standardized. However, generally speaking, the more marijuana that is consumed, the longer it will take to clear the body.
  • Route of entry: Oral ingestion of marijuana (for example, by eating weed-laced snacks, sometimes called “edibles”) is believed to remain in the body longer than inhaled marijuana.
  • Duration of use: Frequent marijuana users tend to have higher levels of THC in their bodies than occasional or one-time users, so frequent users may find that it takes longer for their bodies to fully clear all traces of marijuana.
  • Metabolic rate: The metabolic rate refers to how quickly chemicals and energy break down in the body. People with higher metabolisms break down everything faster, marijuana included, so their bodies will typically take less time to fully clear all traces of THC.

There are many reasons to consider the concentration of marijuana in your body including medical screenings and employment testing. While there are over 100 types of cannabinoids found in marijuana, only a few metabolites are measured during marijuana testing, and most tests focus specifically on measuring THC. These tests may be specific to marijuana, or they may be part of a broader screening panel looking for a variety of illicit drugs. These tests are usually designed to detect THC levels in urine and, less often, blood samples. There are also tests to detect THC in saliva and hair samples, though the accuracy is disputed and these tests are less frequently used as a result.

Regarding your initial question on the exact amount of time marijuana stays in your body, the answer is dependent on both the factors mentioned previously as well as the type of test sample. While the precise time varies considerably for different people and different situations, there are some established scientific estimates. THC may be cleared from detection in urine samples up to three days following a single-use instance and up to four to six weeks for chronic, heavy marijuana users. In blood samples, marijuana usually doesn’t last as long, with blood tests detecting THC up to four hours after single-use and up to ten days for frequent users. Additionally, THC is thought to clear the saliva in 24 to 72 hours and last on hair follicles for up to 90 days, though there is less scientific consensus behind these estimates.

No matter if your question stems from general curiosity or concern regarding an upcoming drug test, hopefully this helped provide some useful information on marijuana metabolization rates. For even more weed info, you can check out the Marijuana, Hash, & Other Cannabis section in the Go Ask Alice! archives.

Last updated Mar 25, 2022
Originally published Dec 06, 1996

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