How Long Does Marijuana Stay in Your System?

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Unlike many other drugs, marijuana can stay within your system for long periods of time. Depending on the frequency of use as well as other factors, weed stays in your system for between 3 and 90 days. This can cause difficulties when you need to pass a drug test, whether you are part of a sports team, an employee, or part of other organizations that test and enforce substance abuse policies.

The length of time that marijuana stays in a person’s system depends on how much body fat they have, the dose they smoke or consume, and how often they use marijuana. There are various reasons why you may be wondering how long marijuana can stay in your system, how it is processed in the body, and how long you can count on the effects to last.

The variety of factors involved makes it difficult to predict exactly how long marijuana’s stay in your system will last. However, this article can help you estimate what you can expect, as explained by Avenues Recovery, a pioneering rehab organization.

What are THC and CBD?

THC is short for tetrahydrocannabinol, and although many other plants contain it, it is mostly connected with marijuana. The most important compound in marijuana is THC, which causes the “high” related to marijuana. Each time a person uses cannabis, whether through smoking or ingesting, THC and many other chemicals enter into their system.

CBD is a chemical found in cannabis plants. CBD doesn't contain tetrahydrocannabinol (THC), the ingredient found in marijuana that causes a high. CBD is most commonly found in oil form, but it’s also sold as a liquid, extract, and capsule.

Many often confuse THC with CBD, and although similar, they have quite a few differences. They both have a similar composition and contain 21 carbon particles, 30 hydrogen particles, and two oxygen particles. However, THC and CBD are organized completely differently. The difference in their chemical structures therefore changes how they affect your body when you smoke or ingest a drug containing them.

Both CBD and THC work with the receptors that discharge neurotransmitters in a person’s head, leading them to influence things like mood and memory. The main difference between them is that THC causes a “high”, but CBD does not. Marijuana use is becoming more and more common these days, especially among teenagers. If you notice signs of marijuana use in your teen, reach out for guidance on how to proceed.

Instead, CBD helps with other areas of the body and can promote physical health. It is often used in over-the-counter drugs and medications and contains no THC. It is derived from the hemp plant, which is related to the marijuana plant, and can be beneficial in its use.

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How Long Does THC Stay In Your System?

THC can stay in the blood for a while and has a very long half-life - the time it takes for the concentration of the substance in the body to reduce to half. 

The half-life depends on the frequency of marijuana use, with studies showing the THC half-life to be 1.3 days in an infrequent user and 5-13 days in a frequent user.

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How Does Your System Process Marijuana?

When someone first ingests or smokes marijuana, the THC and other chemicals enter the body. From there, they begin their path traveling through the brain, the bloodstream, and then to the rest of the body.

If the marijuana is being smoked, then it goes directly into the lungs and is absorbed within seconds. This is because our lungs are fixed with many alveoli, which are the minuscule air sacs where gas exchange happens. These alveoli have a very large surface area, making it simple for THC and different substances to enter the body. THC is also used in vapes as an alternative to smoking as it does not burn the cannabis. Vaped marijuana and smoked marijuana enter the body in the same manner.

Ingesting marijuana, however, delivers the THC straight to the blood rather than traveling through the lungs.

However the substance is administered, it binds to the receptors and blocks the neurotransmitters, causing that euphoric high feeling. These are the usual effects experienced when marijuana is smoked or consumed, but some people may experience different effects.

How Quickly Does Marijuana Start Working?

Once marijuana enters the system, it can take between 2 to 10 minutes to feel the effects when the marijuana is smoked, and 30 to 60 minutes when ingested. In some instances, it can even take as long as 3 hours.

When smoked, the effects of THC peak after about 10 minutes, but the effects can remain for the next 1 to 3 hours. Occasionally, they may still linger even 8 hours after usage. When marijuana is ingested, the THC effects peak after about 2 hours, and may remain for about 24 hours in total.

The time that the effects last changes from person to person, and they depend on the THC levels within the body. It also depends on how much you consume, your body weight and fat percentage, your metabolism, whether you ate beforehand, and your personal tolerance.

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How Long Does Weed Stay in Your System?

Weed can stay in your system long after the actual effects wear off.

Multiple factors affect how long weed will stay in the system and be detectable on a drug test:

  • Frequency of use 
  • The type of test being administered
  • Body fat
  • Dose taken 
  • Sensitivity of the test


Frequency of Use

Frequent users are more likely to fail drug tests than infrequent users. This is because, in a daily user, THC can remain in their system for up to 90 days after their last use, showing up in a hair test. Drug tests can detect even small amounts of THC in the system, so it is important to understand which test can detect different levels of THC.

Someone who uses marijuana one time can expect it to stay in their system for 3 days, and someone who uses it 2 to 4 times a week, or an occasional user, can expect it to stay in their system for 5 to 7 days. If they use marijuana 5 to 6 times a week, it can stay in their system for 33 to 48 days. Even with these estimates, there are always uncommon cases where THC can be detected after even longer periods.

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Urine Test - How Long Does Marijuana Stay in Urine?

In a urine test, Marijuana can be detected in occasional users 3 days after the last use. In moderate users, it can be detected 5 to 7 days after use. In daily users, it can be detected 30 days or more after their last use. Often, THC can be detected even further ahead. Urine testing is the most common form of drug testing because it’s simple, quick, and painless.


Blood Test - How Long Does Weed Stay in Your Bloodstream?

THC can stay in the blood and be detectable just seconds after it is inhaled. A blood test is a far less common drug testing method, as it can only gather results from the past few hours. 

Saliva Test - How Long Does THC Stay in Your Saliva?

THC lasts in your saliva for 1 to 2 days for occasional users and 2 to 3 days for chronic users after their last use. A saliva test can be conducted when the person has inhaled marijuana smoke or has been exposed to it. It is often used by police forces in roadside testing. 

Hair Test - How Long Does Weed Stay in a Hair Follicle?

Small blood vessels allow the weed to reach the hair follicles, and THC can be detected 90 days after usage. A hair test is the least common drug testing method, as it is a little more complicated than urine, blood, and saliva tests.

Marijuana in Your System Chart

Type of Test One time 2 – 4 Times per Month 2 – 4 Times per Week 5 – 6 Times per Week
Urine Test 3 Days 3 Days 5 – 7 Days 30+ Days
Blood Test 3 – 4 Hours 3 – 4 Hours 3 – 4 Hours 3 – 4 Hours
Saliva Test 1 – 2 Days 1 – 2 Days 2 – 3 Days 2 – 3 Days
Hair Test 90 Days 90 Days 90 Days 90 Days


Getting Treatment for Marijuana Addiction

Marijuana is a very addictive substance that can have numerous detrimental effects on your life. Aside from the health issues it can cause, the long half-life of cannabis means that marijuana stays in your system for long periods after use, increasing the risk of failing drug tests. Whether weed is legal in your state or not, this can cause issues for many people.

There are many treatment options available that can help you get your life back, addiction-free. Our experienced addiction counselors are ready to help you and answer any questions you have about addiction. Don’t hesitate to reach out today!

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