Last Updated on August 5, 2020 by Dr. Ronaye Calvert-Conley
How long does weed stay in your system? Specifically, we’ll look at How long it stays in your blood, urine, and hair. Here’s an overview of what is covered in this article:
- Tetrahydrocannabinol (THC) is the primary psychoactive compound in marijuana – i.e., the source of the ‘high’
- THC is broken down quickly into metabolites that are stored in body fat for up to 2 weeks
- The time weed, THC, or the metabolites take to leave the system depends on several factors—including the frequency of use, body, metabolism, and even genetics.
- There are different marijuana tests and some can detect marijuana in your system for up to 3 months.
- Marijuana can be addictive—but help is available. (Find out more on the symptoms of marijuana addiction)
Cannabis (aka., weed, pot, ganja, Mary Jane, herb, or marijuana) is a federally illegal drug that tends to continually attract controversy owing to its devise nature. On the one hand, there are those who push for its legalization—pointing to the touted medicinal properties of some of its compounds (i.e. Cannabidiol- CBD).
Then there’s the health concern due to intoxication, marijuana use disorder, or the risk that Marijuana may be a gateway drug for stronger substances.
Due to these confliction perspectives and a confusing legal framework regulating the compound, it is one of the most prevalent illegal drugs in the United States—and around the globe for that matter.
According to the World Health Organization (WHO), cannabis easily ranks as the “most widely cultivated, trafficked, abused illicit drug.” In fact, approximately 150 million people use cannabis and 50% of all drug seizures are marijuana-related. Many countries are making moves towards legalizing the drug and some countries have already done so—including some states in the U.S.
Judging from its prevalence, it’s not a surprise that questions such as; “How long does marijuana stay in the system?” or “How does it take for weed to leave the system?” are some of the most searched terms in regard to drug tests.
So, what are the answers to these questions? How long does weed stay in the blood, urine, or hair? Even though the effects of Marijuana can be short-lived, weed can remain in the system for a number of days after consumption. Specifically:
- Marijuana or weed can stay in the urine up to 45 days
- Marijuana can stay in the blood up to 75 days
- Marijuana can stay in the hair follicles up to 90+ days
Exactly How Long Does Marijuana Stay in Your System?
Although marijuana only gained widespread public attention in the 20th century, it’s been part of our society for ages. Different communities have leveraged marijuana’s properties for either medicinal uses or it’s psychotropic effects. Weed comes from the leaves, stems, flowers, and seeds of the Cannabis L. Sativaplant. When used medicinally, it can help to ease pain, nausea, inflammation, and some chronic conditions.
How you are affected by marijuana depends on many factors, and the high can be different for you each time you experience it. For example, if you’re smoking marijuana while you’re surrounded by angry or agitated people it may not have the calming effect you might experience when you smoke it at home on your own.
Although the effects of marijuana may fade quickly the substance can stay in your system for considerably longer. It largely depends on how much marijuana you have used and how you used it.
(PS: Marijuana is not to be confused with hemp! The main difference between the two is their THC content. Hemp has less than 0.3% THC—hence not intoxicating and it’s legal at the Federally level in the US.)
What Is THC and How Long Does THC Stay in Your System?
THC (tetrahydrocannabinol) is the psychoactive ingredient in marijuana. Essentially, it’s the part that gets you high, gives you the munchies, and may make you feel paranoid.
The time it takes for you to feel its effects depends on the method of consumption.
- Smoking Marijuana: THC enters your bloodstream via the lungs; is carried to the heart; pumped throughout the body; binds with special receptors (i.e., CB1 and CB2) in the central/peripheral nervous system or certain body organs. As it circulates in the bloodstream, the liver breaks down THC into metabolites. In other words, if marijuana is smoked, it enters your bloodstream quickly and the effects kick in after a few minutes.
- Ingesting Marijuana: In this case, THC enters the bloodstream through the intestinal walls—and it travels directly to the liver to be metabolized/eliminated. The metabolites are then circulated throughout the body and into the brain. For this reason, it may take anywhere from 20 minutes to 1.5 hours before the effects kick in.
Short-term effects of using marijuana—such as memory loss, poor coordination, and reduced problem-solving—will usually ease after 1 or 2 hours. But keep in mind that some minor effects may linger for up to 24 hours.
THC itself is only detectable in your bloodstream for a few hours. This is because it breaks down into metabolites rather quickly. Metabolites are stored in body fat and eventually leave the body through urine and feces.
Some metabolites have a half-life of 20 hours. This means that in 20 hours, only half of the marijuana is still in your system. However, many metabolites that are stored in body fat have a half-life of 10 to 13 days.
For marijuana to be completely out of your system it can take up to 5 to 6 half-lives.
What Influences How Long Marijuana Stays in Your System
The amount of time it takes for weed to leave the system is actually not set in stone – i.e., it largely depends on a variety of factors.
- Duration/Frequency of Use: Marijuana is metabolized slower for chronic users—compared to first-time users.
- Body Fat: The most commonly screened THC metabolite is known as 11-nor-9-carboxy-THC (THC-COOH). This metabolite is fat-soluble—meaning it tends to bind to fat molecules in your body. The more fat molecules you have, the higher the likelihood that THC-COOH will be stored for longer. Exercising may burn fat and help release dormant THC metabolites into your blood system for elimination through feces or urine.
- Metabolism: We’re all different and our bodies function at different capacities—including the rates of metabolism. People with higher metabolic function can eliminate THC and its metabolites faster—hence reducing the time they’re detectable in the body.
- Genetics: Cytochrome P450 superfamily of enzymes affects how the body metabolizes and eliminates THC. And since you inherit different variants of the enzymes, genetics plays a role in how long weed stays in your blood.
- Type/Strain of Marijuana: Different strains of types of marijuana have different amounts of THC. For this reason, if you smoke a more concentrated blunt, the amount of metabolites or THC in your system will likely be higher. This could potentially affect test detection times.
- Test Sensitivity: Drug screening tests typically have a cutoff level – i.e., the drug concentration point in which testing begins. If a test has greater sensitivity, it can detect marijuana in your system for longer.
Although there’s no universal standard for how long THC and its metabolites stay in the body—owing to the variables highlighted above—research allows us to make educated estimates.
The Detection Times of Different Weed Screening Tests
There are many ways marijuana can be detected after your most recent use. They make look for THC and its metabolites in the urine, blood, hair, or even saliva. Each marijuana drug test has a different detection window.
How Long Does Marijuana Stay in Your Urine?
Urine tests are the most common marijuana screening methods due to their ease of administration and affordability. Urine tests are categorized as either Gas Chromatography/Mass Spectrometry (GC/MS) or Immunoassay—with the latter being the more widely used.
Most researchers agree that marijuana can be detected in urine for up to 13 days. However, there is some disagreement about whether smoking or ingesting the substance eliminates it from your body quicker.
Marijuana has been detected in some regular smokers at 45 days after last use. It has also been detected in heavy smokers 90 days after their last puff.
How Long Does Weed Stay in Your Blood?
A blood test can detect THC and its metabolites in a matter of minutes since use. However, some researchers claim that the detection window can run into several days. Marijuana drug tests are rarely used due to their invasive nature—and the availability of equally effective, but passive alternatives.
How Long Does Weed Stay in Your Hair?
As the hair grows, metabolites from marijuana use may be trapped in the core of hair follicles. And since hair grows 0.5 inches every month, a 1.5-inch strand of hair can help detect traces of THC metabolites in hair follicles for up to 90 days.
Although the detection window of hair tests is arguably the longest, the screening method is significantly more expensive than other common tests such as the urine test. There’s also the possibility of transferring THC metabolites from one person to another through exhaled smoke, sweat, and physical contact—making the test relatively inaccurate.
How Long Does THC Stay in Your Saliva or Sweat?
While rarely used, it’s also possible to detected marijuana in oral fluids (i.e., saliva) or sweat. Saliva tests are typically brief—with a detection window of fewer than 24 hours. You can also tamper with the accuracy of the tests by using mouthwash, breath sprays, or any alcohol-based oral rinse.
Marijuana sweat tests use skin swabs or patches that are placed on the skin. The patches are often left in place for up to a week—after which they’re sent to a lab for testing. Their level of accuracy is, however, questionable—not to mention the ease of tampering.
How Accurate Are Urine Test Results for Marijuana or THC?
Urine tests are far more accurate now than they used to be.
The urine undergoes an immunoassay test. If those results are positive, the laboratory will perform another screening with a gas chromatograph mass spectrometer (GCMS). Because two separate tests are performed, false-positive results rarely occur.
Contrary to the popular myth, drinking a lot of water and urinating before a test will not eliminate all the THC from your body. Some herbal teas are marketed as eliminating marijuana from your body but there has been no conclusive research conducted that proves that. In fact, some studies suggest that some of these ‘detox kits’ contain harmful ingredients that could cause liver dysfunction or psychotic symptoms.
You may have heard about chemicals—such as bleach or salt—being introduced to urine samples as a way of contaminating the urine tests to help you pass. This may be possible, but laboratory staff who perform these tests every day are easily able to tell when a sample has been contaminated. A urine integrity test can easily identify masking agents in the urine sample—including the level of dilution, smell, color, and pH level.
What Is the Best Way to Pass a Urine Test for Marijuana?
The only fool-proof way to pass a urine test for marijuana is to stop using marijuana before the test takes place. There is no way to make it leave your system faster—and there are no substances you can take that will give you a false, clean result.
Driving while under the influence of weed, or marijuana, is illegal. This is true even in the countries that have legalized its medicinal or recreational use.
Studies have suggested that using marijuana can impair your driving for up to 3 hours after smoking marijuana. Even though you may feel as if you are perfectly able to drive, your reactions will be considerably slower than normal.
Can You Fail a Drug Test Because of Second-Hand Marijuana Smoke?
The chance of testing positive in a marijuana screening test as a second-hand smoker is possible—but unlikely. Assuming you use the recommended concentration cutoff level of 50 ng/ml, the only way you could test positive as a passive weed smoker was if you were enclosed in a marijuana-filled tight space with no ventilation for several hours. Otherwise, you’re relatively safe—of course, depending on the cutoff concentration and testing method.
The Final Word on How Long Does Weed Stay in Your System?
There is no definitive answer to the above question—but it is certainly true that marijuana stays in your system long after you have stopped feeling its effects. It is best to only utilize marijuana for medicinal purposes.
If you often type “how long does marijuana stay in the system?” in your browser search bar, then your marijuana use habits may be more serious than you realize—or care to admit. Relying on detox kits or techniques of contaminating test samples are only futile attempts to patch a more serious problem.
Revive Recovery offers a wide range of evidence-based and holistic substance abuse treatments to help improve your quality of life. Depending on your marijuana use and personal circumstance, we may also offer marijuana detox programs. Call (844) 467-3848 today—professional help is only a call away!