How Long Does THC Stay in Urine?
Evidence-based answer reviewed against SAMHSA cutoffs and FDA assay documentation · Updated August 2026
Quick answer: Most people clear THC from urine within about 3 days of last use — heavy or daily use stretches that window substantially. Urine immunoassay screens for the metabolite THC-COOH at 50 ng/mL (initial) with GC–MS confirmation at 15 ng/mL (SAMHSA workplace standard).
THC detection windows by test type
Each specimen tells a different story because each samples different biology:
| Test type | Typical THC detection window |
|---|---|
| Urine | occasional: about 3 days · regular: 5–7 days · daily: 10–15 days · heavy: 30+ days in well-documented chronic heavy-use cases |
| Saliva (Mouth Swab) | occasional: 24 hours; regular: up to 72 hours; daily: up to 72 hours |
| Hair Follicles | up to 90 days (standard head-hair window) |
| Blood | occasional: 12–24 hours; regular: up to 2 days |
('Urine remains the employment default because it balances cost, window-length and legal defensibility. Metabolite CONCENTRATIONS (not presence/absence) decide results against cutoff tables, which is why hydration status moves numbers and why validity checks (creatinine, specific gravity) police dilution attempts.',)
Why detection works this way
Urine drug tests do not look for active THC. They look for THC-COOH, an inactive metabolite your liver produces after you consume cannabis in any form — flower, vape carts, dabs, or edibles. Because the metabolite is fat-soluble, it lingers far longer than the high itself, and there is no reliable way to predict an individual's exact clearance time from a chart.
Edibles and smoked cannabis produce the same THC-COOH metabolite, so a test cannot tell how you consumed it. Concentrates such as dabs deliver larger doses of THC, which tends to extend the detection window rather than shorten it.
Delta-8 and THCa products are chemically different from delta-9 but are converted to the same metabolites after use. Most workplace panels cannot distinguish them, so 'hemp-derived' labeling does not make a product test-safe.
Factors that stretch or shrink your window
- Frequency & dose — chronic use saturates stores; single use clears fastest.
- Body composition — fat-soluble metabolites (THC-COOH above all) persist longer with higher body-fat percentages.
- Metabolism & hydration — concentration shifts with fluid intake; elimination speed does not.
- Potency & route — concentrates and edibles deliver more analyte than light use.
Testing cutoffs in plain language
Urine immunoassay screens for the metabolite THC-COOH at 50 ng/mL (initial) with GC–MS confirmation at 15 ng/mL (SAMHSA workplace standard). A specimen under the initial cutoff reports negative without further work; a screen above cutoff gets confirmed by mass spectrometry before anyone sees a positive.
Planning ahead? Our at-home drug test guide covers retail kits that mirror lab screens.
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Evidence-based ways to pass a drug test for THC — realistic timelines, what works, what backfires, and dilution flags to avoid. Full guide →
How Long Does Weed Stay in System for Drug Test?
How long THC stays detectable in your system (all test types) — urine, hair, saliva & blood windows explained with cutoffs. Full guide →
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Evidence-based ways to pass a drug test for THC — realistic timelines, what works, what backfires, and dilution flags to avoid. Full guide →
How Long Does Weed Stay in Urine Drug Test?
Urine detection runs roughly about 3 days after last use; hair extends to ~90 days and saliva stays within 24–72 hours. Full breakdown in our detection guides.
How Long Does Weed Stay in Urine for Drug Test?
Urine detection runs roughly about 3 days after last use; hair extends to ~90 days and saliva stays within 24–72 hours. Full breakdown in our detection guides.
Can secondhand exposure cause a positive?
Practically impossible for cannabis smoke at modern cutoffs — the Johns Hopkins hot-box study found transient levels well under confirmatory thresholds. Edible ingestion is different.
Do prescriptions count against me?
No — verified prescriptions report as negative through the Medical Review Officer. Declare medications at collection and answer the follow-up call.
Sources & further reading
- SAMHSA — Mandatory Guidelines for Federal Workplace Drug Testing Programs (cutoffs, MRO process)
- DOT — 49 CFR Part 40 procedures for transportation workplace testing
- Brahm NC et al., Mayo Clinic Proceedings 2008;83(1):66–76 — false-positive cross-reactivity reference
- FDA — drug-of-abuse test device labeling (detection window conventions)