How Long Does Weed (Marijuana) Stay in Your System?
It varies according to dose
Weed, also known as marijuana or cannabis, is usually detectable in bodily fluids for 1 to 30 days after last use. As with other drugs, it may be detectable in hair for several months.
Weed detection windows depend on how much you smoke or ingest, as well as how often. In general, higher doses and more frequent use are associated with longer detection times.
For daily users, cannabis may be detectable for several months after last use. The longest-reported detection times are more than 90 days.
Read on to find out the detection windows for cannabis in urine, blood, saliva, hair, and more.
Drug tests measure weed and its by-products, or metabolites. These metabolites remain in your system long after weed’s effects have worn off.
According to Mayo Clinic Proceedings, weed is detectable in urine for the following amounts of time after last use:
- Occasional users (up to three times a week): 3 days
- Moderate users (four times a week): 5 to 7 days
- Chronic users (daily): 10 to 15 days
- Chronic heavy users (multiple times a day): more than 30 days
Cannabis metabolites are fat-soluble, which means they bind to fat molecules in your body. As a result, it can take some time for them to leave your system.
According to an article in Therapeutic Drug Monitoring, weed is typically detectable in the blood for 1 to 2 days. However, in some cases, it’s been detected after 25 days. Chronic heavy use increases the length of time that it can be detected.
Weed is detectable in the bloodstream within seconds of inhalation. It’s distributed to the tissues. Some of it is reabsorbed in the blood and broken down. Its metabolites may remain in the bloodstream for days.
Blood testing may be used in laboratory settings or to indicate recent use of weed.
According to a 2014 review on cannabinoids in oral fluid, weed is detectable in saliva for the following amounts of time after last use:
- Occasional users: 1 to 3 days
- Chronic users: 1 to 29 days
Weed can enter the saliva through smoking and exposure to smoke. However, its metabolites are only present in saliva when weed has been smoked or ingested.
In jurisdictions where weed is legal, oral fluid may be used for roadside testing.
Hair follicle tests assess drug use for up to 90 days . After use, weed reaches the hair follicles via small blood vessels. Trace amounts may remain in the hair.
Since hair grows approximately 0.5 inches per month, a 1.5-inch hair segment taken close to the scalp can provide a window of weed use for the past three months.
The active ingredient in weed is a chemical substance called THC, which stands for delta-9-tetrahydrocannabinol. THC that enters your body is absorbed into the bloodstream.
Some THC is temporarily stored in organs and fatty tissues. In the kidneys, THC can be reabsorbed into the bloodstream.
THC is broken down in the liver. It has more than 80 metabolites, but the most significant ones are 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol) and THCCOOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol).
Drug tests look for these metabolites, which stay in your body longer than THC. Eventually, THC and its metabolites are excreted in urine and stool.
A number of factors affect how long weed stays in your system. Some of these factors, such as your age, gender, and body mass index (BMI), aren’t related to the drug itself, but to how your body processes and metabolizes the drug.
Other factors are related to weed and how you use it. This includes how much you take (dose) and how often (frequency). Higher doses and more frequent use tend to increase the amount of time it takes to eliminate weed from your system.
More potent weed, which is higher in THC, may also stay in your system for longer. Weed that’s ingested may also remain in your system slightly longer than weed that’s smoked.
There isn’t much you can do to speed up the amount of time it takes for weed to leave your system.
Once it’s entered your system, your body needs time to break it down. Exercising, eating healthy, and staying hydrated may help, but not drastically.
There are a number of weed detox remedies and kits available on the internet. Many require drinking a lot of water to dilute your urine, and then using herbal supplements such as creatinine or vitamin B-12 to mask the dilution.
These kits don’t work reliably.
Weed’s effects appear quickly, usually within 15 to 30 minutes after smoking. It can take one or two hours to feel weed’s effects when it’s ingested.
Weed’s active ingredients produce a short-term “high.” Common effects include:
- sense of well-being
- sense of relaxation
- feeling that time is slowing down
- giggling or chattiness
- altered sensory perception
Other short-term effects include:
- inability to focus
- increased appetite
- coordination problems
- rapid heart rate
- dry mouth and eyes
- feeling sick or faint
- anxiety or paranoia
In rare cases, high doses of weed can cause hallucinations, delusions, and psychosis.
Smoking or ingesting weed on a regular basis can have additional effects on your mind and body. You might be at an increased risk of developing:
- cognitive impairments
- memory impairments
- learning impairments
- cardiovascular diseases, such as heart disease and stroke
- respiratory illnesses, such as bronchitis and lung infections
- mood disorders, such as depression and anxiety
- hallucinations and psychosis
If you use weed while you’re pregnant or breastfeeding, there’s a greater chance that your baby will have birth defects or problems with brain development.
Weed’s short-term effects start to taper off after one to three hours. Some effects, like memory problems or trouble sleeping, can last a few days.
Researchers don’t know how long the effects of chronic use last. Long-term effects can last days, weeks, or months after weed use has ended. Some effects may be permanent.
Weed may stay in your system anywhere from several days to several months after last use. Detection windows depend on the drug test used and other factors, such as whether you smoke or ingest weed on a regular basis.Weed is detectable in bodily fluids for up to 30 days after last use. For daily users, weed may be detectable for several months after last use. The longest-reported detection times are more than 90 days. Here’s how long it’s detectable via each type of drug test, whether you can metabolize it faster, and more.
How long can you detect marijuana in the body?
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Tetrahydrocannabinol, the chemical in marijuana that makes people feel “high,” can stay in the body for several days or even weeks.
The length of time this chemical stays in the body or continues to show in a drug test depends on many factors. These include:
- how much body fat a person has
- how often they consume the drug
- how much someone smokes
- the sensitivity of the drug test
Drugs such as alcohol may completely disappear from the body in just a few hours. In comparison, weed lingers much longer.
Drug tests can detect tetrahydrocannabinol, or THC, in urine, blood, and hair for many days after use, while saliva tests can only detect THC for a few hours. This is because of the way the body metabolizes THC.
THC is a lipid-soluble chemical. This means that it binds to fat in the body, which increases the length of time it takes for someone to eliminate THC completely.
Share on Pinterest Marijuana can stay in the body from 3 to 30 days and sometimes longer.
Research on the amount of time a test can detect marijuana shows a wide range of averages. Research from 2017 estimates a detection window for a single marijuana cigarette of about 3 days.
The same study emphasizes that detection windows vary and depend on how often a person smokes.
- For someone smoking marijuana for the first time, tests may detect it for about 3 days.
- In someone who smokes marijuana three or four times per week, the detection window is 5–7 days.
- For people who smoke marijuana once a day or more, tests may detect it in their system for 30 days or longer.
Detection windows also depend on the kind of test a person undertakes. General estimates for various marijuana tests are as follows:
- Urine tests can detect marijuana in the urine for approximately 3–30 days after use.
- Saliva tests can detect marijuana for approximately 24 hours after use. Some saliva tests have detected marijuana for up to 72 hours.
- Hair tests are the most sensitive tests, detecting THC for up to 90 days after use. However, these tests are testing the oil in skin that transfers to hair, and so they may occasionally show a false positive. A person who comes into contact with a THC user could, theoretically, test positive on a hair test.
- Blood tests can only detect THC for 3–4 hours.
Drug tests can detect relatively small quantities of THC, and the amount of THC in a given marijuana cigarette varies. However, little research has examined exactly how much a person must smoke to fail a drug test.
Studies consistently find that frequent weed users are more likely to fail drug tests than infrequent users. A 2012 study in the journal Clinical Chemistry examines marijuana users smoking a single cigarette with 6.8 percent THC.
Urine concentrations of THC were highest 0.6 to 7.4 hours after smoking. Using a highly sensitive urine test, researchers detected THC in the urine of 100 percent of frequent users and 60–100 percent of infrequent users.
A 2017 study reports on testing where hair samples from 136 marijuana users reporting heavy, light, or no use of marijuana. For the study, researchers cut hair into 1-centimeter sections to test for exposure of up to a month prior.
Some 77 percent of heavy users and 39 percent of light users produced positive tests. No non-users had positive test results, suggesting that false positives in hair tests are relatively rare.
Numerous factors influence whether a test detects marijuana, including the following:
More sensitive tests can detect lower doses of marijuana. Tests include blood, urine, hair, and saliva.
Marijuana drug tests look for THC, not marijuana. So the amount of THC that a person consumes is the significant factor.
The effects of THC are cumulative. This means that a person who smokes several times over several days has consumed a higher THC dose than someone who smokes once, and so they are more likely to test positive.
The strength of each dose of THC also matters. Without sensitive laboratory equipment, a person cannot reliably determine the strength of their marijuana.
How “high” a person feels is also not a reliable measure, because numerous factors other than THC dose can intensify or weaken this feeling.
Since fat stores marijuana, people with higher body fat concentrations may metabolize marijuana more slowly than a person with less body fat.
Body mass index (BMI) is one way to judge body fat. However, since weight, and therefore BMI, increase with muscle mass, BMI is not a perfect measure of body fat.
Typically, females have more body fat than males. This means that females may metabolize marijuana slightly more slowly.
Dehydration increases concentrations of THC in the body. While drinking lots of water is unlikely to affect a drug test significantly, severe dehydration might.
Exercise will not significantly change the rate at which the body metabolizes THC. Exercising before a drug test, however, might.
A small study of 14 regular marijuana users assesses the effects of 35 minutes of exercise on a stationary bike. The results conclude that THC concentrations increased by a statistically significant amount, suggesting that exercise right before a drug test may increase the likelihood of a positive test result.
The researchers believe that exercise may cause fat cells to release THC. In their results, people with higher BMI had more significant increases in THC levels.
For a drug test to be negative, the body must eliminate THC from the system, as well as metabolic chemicals that have links to THC. People with faster metabolisms typically eliminate THC more quickly than those with slower metabolisms.The body processes marijuana at varying rates, which may change depending on dose, hydration, body fat percentage, and, sometimes, the sensitivity of the test. Learn more here. ]]>