How Long Does Marijuana Stay in Your System? (Urine, Saliva, Hair)

The amount of time marijuana remains in your system depends on many factors, such as how much THC is in the marijuana, how often you use, how much you use, and your metabolism. If you’re a daily user, the drug can remain in your system for up to a month or longer.

Detox kits are not scientifically proven to speed up the detox process and may contain unknown chemicals that could be unsafe.

Marijuana Length of Effects

The National Institute on Drug Abuse reports that the effects of marijuana include:1

  • Distorted senses.
  • Altered sense of time.
  • Mood changes.
  • Impaired coordination.
  • Trouble thinking and problem-solving.
  • Impaired memory.

Not all users of marijuana enjoy the experience. In fact, many people who use marijuana report unpleasant side effects, such as hallucinations, anxiety, and paranoia.1

The effects can develop within minutes if the drug is smoked. If eaten, users may not feel any effects for a few hours. The effects normally last 3-4 hours but can last longer if the drug is eaten.4

Marijuana does not easily leave the body. Most cannabinoids, including THC, are stored in fat cells. This means that the effects of marijuana or hashish can reoccur for 12-24 hours after use because the chemicals are slowly released from fatty tissue.4

How long does THC stay in your system?

The length of time that marijuana will show up on a drug test varies greatly from person to person.

Variables that can affect how long marijuana will show up on a drug test include:5

  • Dose of THC ingested.
  • How often the person used.
  • Timing of drug test relative to last use.
  • Rate of release of THC or other cannabinoids from tissue.
  • Level of hydration.

The amount of THC in marijuana will affect how long it takes for the body to metabolize the drug. However, keep in mind that other factors can affect how long marijuana stays in your system. These include the amount of marijuana you used, how you used it, how often you used, and your metabolism. The amount of THC in the plant is just one variable that will determine how long the drug remains in your system.9

Marijuana can stay in your system for up to a month

How Long Does Marijuana Show Up In Urine?

The amount of time that marijuana will show up on urine screenings depends largely on how often the individual uses. The following are some basic guidelines on how long the drug will show up on a urine test based on how often you use:5

  • Less than twice per week smoker: 1-3 days.
  • Several times per week smoker: 7-21 days.
  • Daily smoker: 30 days or longer.
  • Oral ingestion (edibles): 1-5 days.

Worried about your marijuana use? Take our free and confidential addiction assessment today.

How Long Does Synthetic Marijuana Stay in Your System?

Synthetic cannabinoids can be detected in drug tests. They can be detected up to 72 hours in urine and up to 24-48 hours in saliva.6

That said, some synthetic cannabinoids could have longer long half-lives. That means they could have longer effects and show up in a urine test beyond the timeframe listed above. In addition, the batches of synthetic cannabinoids can vary both in terms of the substances present and their quantity. This increases the risk of overdose.6

What About Other Types of Drug Screens?

THC can be detected in saliva within minutes and up to 2 days.7 It can be detected in hair up to 90 days.8

For blood tests, marijuana can show up on a test for 4-8 hours for people who use several times a week or more, and for 3-4 hours for casual or infrequent users. 9

Can You Fail a Drug Test From Secondhand Smoke?

You are at risk of failing a drug test if you inhale secondhand marijuana smoke. But the odds are small.

Studies show that very little THC goes into the air when a person exhales marijuana smoke. Research suggests that unless you are in an enclosed space and you inhale lots of smoke for hours at close range, you probably won’t fail a drug test.1

Detoxing From Marijuana

Many Internet sites claim to be able to eliminate marijuana from the body fast enough to pass a drug test. These allegedly rapid detox suggestions include drinking lots of water, green tea, cranberry juice, and even alcohol. Dietary supplements or over-the-counter medications, like vitamin B3, cayenne, milk thistle, or exclusive herbal remedies, are also marketed to help the body process marijuana faster.

However, none of these methods are scientifically proven to speed up the detox process, and some kits or drugs specifically marketed for this purpose may be dangerous and contain unknown ingredients. There is no proven method for accelerating this process.

None of these methods are scientifically proven to speed up the detox process.

The detox process can be tough for people who struggle with marijuana dependence, so contact a healthcare provider or enroll in medical detox at an inpatient or outpatient program for help safely withdrawing from this drug. People who struggle with an addiction should seek out a rehabilitation program or some form of therapy to help them recover.

Using Marijuana

Marijuana refers to the dried leaves, flowers, stems, and seeds of the cannabis sativa or cannabis indica plant. These plants contain THC and other similar compounds, which are responsible for the mind-altering effects of the drug.1

The most common way to use marijuana is to smoke it through a joint, blunt, bowl, or bong. The most common way to use marijuana is to smoke it through a joint, blunt, bowl, or bong. Some people also use vaporizers to avoid inhaling the smoke.1

People also mix marijuana in food (edibles), such as brownies, cookies, or candy, or brew it as a tea. Edible forms of marijuana are growing in popularity. In California alone, edible sales reached $180 million in 2016, and sales in the U.S. and Canada could top $4.1 billion by 2022.1,2,3

A newer method is to smoke or eat different forms of THC-rich resins.1

  1. National Institute on Drug Abuse. (2018). DrugFacts: Marijuana.
  2. Montgomery, M. (2017). Edibles Are The Next Big Thing For Pot Entrepreneurs. Forbes.
  3. Schiller, M. (2018). Edibles Sales Projected to Surpass $4.1 Billion by 2022, According to New Report. Cannabis Business Times.
  4. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
  5. Redwood Toxicology Laboratory. Marijuana Drug Information.
  6. Redwood Toxicology Laboratory. Synthetic Cannabinoids Drug Information.
  7. Redwood Toxicology Laboratory. (2014). Laboratory Testing Reference Guide.
  8. The University of Arizona. (2018). Biological Tests.
  9. University of Columbia: Go Ask Alice. Marijuana: How long does it hang out in the body?

About The Contributor

Dan Wagener
Dan Wagener


Dan Wagener, M.A., is a Senior Web Content Editor at American Addiction Centers (AAC). Before AAC, he worked for a government contractor in the Washington, D.C. area, where he edited websites for the Substance Abuse and Mental Health Services... Read More

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