Quick answer
Weed / THC (cannabis) is typically detectable in urine for about 3 days after occasional use; 5–7 days after regular use; 10–15 days after daily use; 30+ days in well-documented chronic heavy-use cases after heavy use. It is screened on standard 5-panel, 10-panel, 12-panel, DOT drug tests.
Screened on: 5-panel 10-panel 12-panel DOT
Typical cutoff: Urine immunoassay screens for the metabolite THC-COOH at 50 ng/mL (initial) with GC–MS confirmation at 15 ng/mL (SAMHSA workplace standard).
Detection window by test type
| urine | |
|---|---|
| Occasional use | about 3 days |
| Regular use | 5–7 days |
| Daily use | 10–15 days |
| Heavy use | 30+ days in well-documented chronic heavy-use cases |
| saliva | |
| Occasional use | 24 hours |
| Regular use | up to 72 hours |
| Daily use | up to 72 hours |
| hair | |
| Any use | up to 90 days (standard head-hair window) |
| blood | |
| Occasional use | 12–24 hours |
| Regular use | up to 2 days |
Ranges reflect typical published detection windows and vary with dose, frequency, body composition, hydration and the assay used.
Key details
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.
Secondhand exposure alone virtually never produces a failing level. The classic Johns Hopkins 'hot box' study found non-users exposed to extreme smoke produced only transient low-level positives, and modern 15 ng/mL confirmation cutoffs eliminate almost all passive-exposure positives.
Several states restrict how employers may act on marijuana-only positives, particularly for off-duty recreational or medical use (New York, New Jersey, California, and others). A positive THC result is not automatically grounds for discipline everywhere — check your state's off-duty conduct statutes.
False positives & cross-reactivity
- No over-the-counter medication is proven to cause a confirmed THC positive.
- Older immunoassays occasionally reacted with ibuprofen or naproxen; modern assays have largely corrected this, and GC–MS confirmation resolves it.
- Dronabinol (prescription Marinol) and hemp-seed products containing trace THC can produce genuine positives — declare your prescription through the Medical Review Officer.
Frequently asked questions
How long does weed / thc (cannabis) stay in your system?
In urine, typical detection is about 3 days (occasional use); 5–7 days (regular use); 10–15 days (daily use); 30+ days in well-documented chronic heavy-use cases (heavy use). Hair can detect use for up to 90 days and saliva/blood windows are usually shorter.
Will weed / thc (cannabis) show up on a standard drug test?
Yes — Weed / THC (cannabis) is screened on standard panels (5-panel, 10-panel, 12-panel, DOT).
Can anything cause a false positive for weed / thc (cannabis)?
No over-the-counter medication is proven to cause a confirmed THC positive. Older immunoassays occasionally reacted with ibuprofen or naproxen; modern assays have largely corrected this, and GC–MS confirmation resolves it. Dronabinol (prescription Marinol) and hemp-seed products containing trace THC can produce genuine positives — declare your prescription through the Medical Review Officer.
How accurate are these detection windows?
They are typical ranges from published literature and assay documentation, not guarantees. Clearance depends on dose, frequency, metabolism and the specific test cutoff used.
Related substances
Cite this page
DrugPanels. “Weed / THC (cannabis) Detection Time.” https://drugpanels.com/detection/weed/. Accessed 2026-09-10.
Sources
- Huestis MA, Cannabis impact on drug testing (NIDA monographs / Forensic Science Reviews) — National Institute on Drug Abuse — nida.nih.gov
- Rohrich et al., passive cannabis exposure studies, Journal of Analytical Toxicology — Journal of Analytical Toxicology / PubMed — pubmed.ncbi.nlm.nih.gov
- SAMHSA Mandatory Guidelines for Federal Workplace Drug Testing Programs — Substance Abuse and Mental Health Services Administration — samhsa.gov
Detection windows describe typical ranges from the published literature and assay documentation; individual results vary. See our methodology.