For most people, cannabis stays in your system for 3 to 30 days in urine, 1 to 2 days in blood, 1 to 3 days in saliva, and up to 90 days in hair. One-time users often clear THC in a few days. Daily users and people who use concentrates can test positive for a month or longer. The test matters as much as the person, because each method looks for different compounds at different cutoffs.
Cannabis Drug Test Detection Times Chart Guide
Detection windows by test type
- Urine: 3 to 30 days for most users. Heavy daily use can reach 45 days or more.
- Blood: 1 to 2 days. Up to 7 days after frequent, high-dose use.
- Saliva (oral fluid): 1 to 3 days. A single hit can clear in under 24 hours.
- Hair: up to 90 days, set by the length of the sample (about 1.5 inches covers 90 days).
Urine screens are the most common pre-employment test in the US, which is why the 3 to 30 day range gets the most attention. Blood tests catch recent use and miss anything older than a few days. Hair tests have the longest window and the fewest ways to beat them.
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What changes how long THC stays in your system?
Four factors do most of the work: how often you use, how much body fat you carry, how your liver processes THC, and how you consume it. Two people can smoke the same joint and show very different results two weeks later.
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Frequency and dose
THC and its metabolites store in fat tissue. Each session adds to the pool. A person who uses once a month clears the metabolite THC-COOH in days. A person who uses every day builds a reserve that leaks back into the bloodstream for weeks after the last session.
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Body fat and metabolism
THC is fat-soluble, so higher body fat means a larger reservoir and a longer detection window. Metabolism plays a role too. People with fast liver enzymes (CYP2C9 and CYP3A4 activity) break THC down sooner, though not fast enough to turn a 30-day window into a 3-day one.
Route of use
Smoking and vaping send THC to the brain in seconds. Edibles pass through the liver first, where THC converts into 11-hydroxy-THC, a compound that hits harder and lasts longer. One 10 mg edible can keep urine positive for several days in a casual user. Dabs and vape concentrates push the numbers higher because the dose runs far above a joint.
Potency and product type
Flower in the 1990s averaged around 4% THC. Legal dispensary flower today often tests 20% to 30%, and concentrates run 60% to 90%. Higher input means more metabolite to store and a longer tail.
How does each test detect cannabis?
Urine tests
Urine tests screen for THC-COOH, the inactive metabolite your body makes after processing THC. The standard immunoassay cutoff is 50 ng/mL, with confirmation (GC-MS or LC-MS/MS) at 15 ng/mL. A positive screen that fails confirmation does not count as a positive result.
Blood tests
Blood tests measure delta-9-THC itself, not the metabolite. That makes them a marker of recent use, usually within 2 to 4 hours of peak. They show up in DUI cases and some post-accident workplace testing, not in routine pre-employment screening.
Saliva tests
Oral fluid tests look for parent THC in the mouth. Levels drop fast because saliva clears THC within hours. Residue in the mouth from smoking can cause a positive reading for up to 24 hours after use even when impairment has passed.
Hair tests
Hair tests detect metabolites trapped in the follicle as hair grows. A standard 1.5-inch sample covers about 90 days of history. Hair tests cost more and cannot be run on people with very short or chemically treated hair, so they stay less common.
Can you flush THC from your system faster?
No proven method clears THC faster. Water, cranberry juice, saunas, niacin, and detox kits either fail to change metabolite levels or work by diluting urine. Labs flag diluted samples when creatinine falls below 20 mg/dL, and a diluted result can be treated as a refusal.
Exercise is a gray area. Burning fat can release stored THC-COOH into the blood, which may raise urine levels in the days right before a test. If you have a test coming, heavy training in the final week is a bad idea. The only lever that works is stopping use sooner.
How long does cannabis stay in your system after edibles?
Edibles produce the longest detection window of any route. The liver converts THC to 11-hydroxy-THC, which is more potent and clears slower than inhaled THC. A daily edible user can test positive in urine for 30 days or more, while a one-time 10 mg dose often clears in 2 to 5 days.
Does CBD or delta-8 show up on a drug test?
Isolate CBD products should not trigger a positive result because they contain no THC. Full-spectrum and broad-spectrum CBD can carry trace THC, and daily high doses of full-spectrum oil can build enough metabolite to cross the 50 ng/mL screen. Delta-8 and delta-10 gummies carry a bigger risk since some immunoassays cross-react with those cannabinoids. State legality does not change what a lab detects.
FAQ: common questions about cannabis detection
How long does cannabis stay in your system for a one-time user?
A single small dose clears urine in 1 to 3 days for most people. A large dose, a high-potency concentrate, or an edible can stretch that to a week.
Can cannabis show up after 30 days?
Yes. Long-term daily users, people with high body fat, and concentrate users can test positive at 45 days and beyond. The 30-day figure is a common ceiling, not a hard rule.
Do at-home tests match lab results?
Not always. Home tests use a 50 ng/mL cutoff. Labs screen at 50 ng/mL and confirm positives at 15 ng/mL, so a faint line at home can still confirm as positive at a lab.
Does drinking water help?
Water lowers the concentration of THC-COOH in urine for a few hours. It does not remove metabolites. Labs check for dilution, and an invalid sample can hurt you more than a positive one.
How long does THC stay in your blood?
Delta-9-THC clears blood in 1 to 2 days for most users. Chronic users may show traces for up to a week after the last dose.