How Long Does Cannabis Stay in Your System? Detection Times

Short answer

Most casual cannabis users test negative on a urine screen within 3 days. Daily, long-term users can stay positive for 30 days or longer. Blood tests clear in about 1 to 2 days, saliva in 1 to 3 days, and hair can hold detectable THC for up to 90 days. The type of test matters as much as the person taking it.

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Detection windows by test type

Urine

Urine screens look for THC-COOH, the main metabolite the liver produces when it breaks down THC. Federal workplace testing uses a 50 ng/mL immunoassay screen and a 15 ng/mL confirmation cutoff. Occasional use clears in 1 to 3 days. Use several times a week runs up to 10 days. Daily flower, edibles, or concentrates can stay positive for 30 days or more.

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Blood

Blood tests measure active THC rather than stored metabolites, so the window is short. Occasional users clear in 1 to 2 days. Heavy daily users may show detectable levels for up to 7 days. Blood draws are rare outside of impairment investigations and research.

Cannabis Detection Times in Urine, Blood, Hair, and Saliva

Saliva

Oral fluid swabs detect THC for roughly 1 to 3 days after smoking or vaping. Edibles can extend the window slightly because absorption is slower. Roadside and pre-employment oral swabs are common because collection is easy to supervise.

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Hair

Hair follicle testing has the longest window, up to 90 days. A standard 1.5 inch sample reflects about 90 days of growth. THC deposits in the follicle as the hair forms, so a single heavy session can register if timing lines up with growth.

What changes your timeline

• Frequency and dose: more THC in the body takes longer to clear.
• Body fat: THC-COOH is fat soluble, so leaner users often clear faster.
• Metabolism and liver function: faster metabolizers process metabolites sooner.
• Route of use: edibles and concentrates deliver higher doses than a single joint.
• Hydration and activity level: both shift how quickly the body moves metabolites out.
• Age and overall health: both affect elimination speed.

Does anything clear THC faster?

No product has evidence for speeding elimination. Drinking water dilutes urine, but labs test creatinine levels and flag samples that look diluted. Exercise burns fat and can release stored metabolites, which may raise levels right before a test. Detox kits, niacin, and herbal cleansers do not have clinical support. Time and abstinence remain the only reliable path.

How to plan around a test

1. Confirm which test you face: urine, blood, saliva, or hair.
2. Count the days since your last use and match that against the window above.
3. Buy at-home urine strips to track your own clearance if you use daily.
4. Hydrate normally in the 24 hours before a test rather than in a panic.
5. Skip strenuous workouts in the 2 to 3 days before a urine screen.

When to expect a negative result

One-time users typically clear a urine screen in 3 days. Weekend users often clear in 5 to 7 days. Anyone using daily for months should plan on 30 days minimum, with 45 to 60 days common for heavy concentrate users. At-home tests give the clearest picture of your own pattern.