How Long Does Marijuana Stay in Your System?
People who smoked marijuana in the last:
- 30-45 days can fail a urine test
- 60-75 days can fail a blood test
- Up to 90 days can fail a hair follicle test
Though the effects of THC, the main chemical in marijuana, wear off within a few hours of ingesting marijuana, traces of the chemical can remain in the body for weeks. There is no perfect formula for determining exactly how long marijuana stays in someone’s system during a urine, blood, saliva or hair drug test.
Factors that Affect How Long Marijuana Stays in Urine, Blood or Hair
Because of the variety of factors involved, it is difficult to estimate the amount of time that marijuana will remain traceable through testing. The only sure way to avoid the detection of marijuana use is to remain abstinent from the drug.
- Marijuana itself does not stay in the body for long periods of time, which is why hemp and other marijuana-based products are safe to use and will not cause you to fail a drug test for marijuana.
- Testing urine is one of the most common methods for determining marijuana use. With a urine test, 9-carboxy-THC is often the substance that is being detected, rather than actual marijuana.
- When it comes to testing for marijuana use, blood tests are not often utilized. This is because blood tests have a narrow window of time to detect marijuana use. These tests typically cannot detect marijuana use unless the test is done within a few hours of when a person smokes or ingests marijuana, which is when the THC is still in the bloodstream. Unlike urine tests, blood tests do not identify metabolites (9-carboxy-THC) which are the longer-lasting compounds produced by marijuana use. One occasion in which a blood test may be utilized is if law enforcement suspects someone has been driving under the influence of marijuana.
- Similar to blood tests, saliva tests can only detect marijuana within a few hours of use, and cannot detect any metabolites from marijuana use.
- Like a urinalysis, testing hair strands can detect metabolites in the body after they pass from the bloodstream to the hair follicle.