How Long Does It Stay in Your System?
Published urine detection windows and plasma half-lives, taken directly from two clinical reference tables. Every figure below shows the source it came from, and where no published figure exists, we say so instead of estimating one.
- Published sources, named on the page
- Method and formula shown
- Limits stated with the result
Most commonly screened drugs are detectable in urine for about 1 to 4 days after use. Cannabis is the main exception — casual use clears in 1 to 3 days, while chronic use can remain detectable for 4 to 6 weeks. Detection depends on the drug, the use pattern, and the test’s cutoff, not on body flushes or timing tricks.
Also known as: marijuana, weed, hashish
What the lab measures: 11-nor-9-carboxy-delta-9-THC (THC-COOH)
Cannabis (THC): THC-COOH is stored in fat and released slowly, which is why chronic use extends urine detection far beyond any other common drug. ARUP reports an overall window of 1–45 days across all use patterns. Most laboratory testing does not distinguish delta-9 from delta-8 isomers.
These are published reference ranges, not predictions. ARUP states plainly that detection limits and plasma half-lives should be treated as estimates. Actual results depend on dose, metabolism, liver and kidney function, hydration, the specific assay, and its cutoff concentration. No calculator can tell you whether you will pass a particular test, and this page should not be used to try to time one.
Urine Detection Windows and Plasma Half-Lives
Every substance covered by this tool, side by side. Figures marked SP come from the StatPearls urine detection table; figures marked ARUP come from ARUP Laboratories' October 2023 reference.
| Substance | Typical urine window | Chronic or heavy use | Plasma half-life |
|---|---|---|---|
| Alcoholethanol, EtOH | 12–24 hours (ethanol itself)SP | 1–4 days (EtG / EtS metabolite testing)ARUP | 2–14 hours |
| Cannabis (THC)marijuana, weed, hashish | 1–3 days (casual use)SP | 5–10 days daily use; 4–6 weeks chronic useSP | 4–12 hours |
| Cocainecoke, crack | 1–3 daysSP | No separate published figure | 5.5–7.5 hours (benzoylecgonine); 0.7–1.5 hours (cocaine) |
| Methamphetaminemeth, crystal | 2–4 daysSP | No separate published figure | 6–17 hours |
| AmphetamineAdderall, Dexedrine, Vyvanse, speed | 1–5 daysARUP | No separate published figure | 7–34 hours |
| Heroindiacetylmorphine, dope, smack | Under 1 day (6-MAM); 1–3 days (morphine)ARUP | No separate published figure | 0.1–0.25 hours (heroin); 1.3–6.7 hours (morphine) |
| Codeine / Morphineprescription opiates | 1–3 daysSP | No separate published figure | 1.9–3.9 hours (codeine); 1.3–6.7 hours (morphine) |
| Fentanylsynthetic opioid | 3–5 days (acute use)SP | Up to 30 days (chronic use)SP | 3–12 hours |
| OxycodoneOxyContin, Percocet, Roxicodone | 1–3 daysARUP | No separate published figure | 3–6 hours |
| Alprazolam (short-acting benzo)Xanax | 1–4 daysARUP | Up to 30 days with chronic benzodiazepine dosingSP | 6–27 hours |
| Diazepam (long-acting benzo)Valium | 1–7 daysARUP | Up to 30 days with chronic benzodiazepine dosingSP | 21–37 hours |
| MethadoneDolophine, Methadose | 2–4 daysSP | 1–14 days reported by ARUPARUP | 15–55 hours |
| BuprenorphineSuboxone, Subutex, Sublocade | 1–7 days (buprenorphine)ARUP | 1–14 days (norbuprenorphine metabolite)ARUP | 26–42 hours (buprenorphine); 15–150 hours (norbuprenorphine) |
| MDMAecstasy, molly, XTC | 1–3 daysARUP | No separate published figure | 6–10 hours |
| PCPphencyclidine, angel dust | 2–7 days (acute use)SP | Up to 30 days (chronic use)SP | 7–46 hours |
| Kratommitragynine, 7-OH | No published window in either reference tableARUP | No separate published figure | Not published in these tables |
SP = StatPearls, Drug Testing, Table 1. ARUP = ARUP Laboratories, Drug Plasma Half-Life and Urine Detection Window (BD-TS-013, Rev 5, October 2023).
What Actually Changes a Detection Window
Published ranges exist because the same drug clears differently in different people and different tests. These are the variables behind the range.
How much, and how often
Repeated use loads the body with more parent drug and more metabolite to excrete. For cannabis this is the dominant variable — THC-COOH is stored in fat and released slowly, which is why chronic use stretches the window to weeks while casual use clears in days.
The assay and its cutoff
A test does not detect a drug's presence; it detects a concentration above a defined cutoff. A lower cutoff extends the window, a higher one shortens it. Two laboratories testing the same sample can legitimately report different results for this reason.
What the lab is actually measuring
Most screens target a metabolite rather than the drug itself, and metabolites persist far longer than the parent compound. That is why a detection window is usually much longer than the plasma half-life.
Metabolism, liver and kidney function
Clearance depends on how quickly the liver metabolizes the drug and the kidneys excrete it. Age, illness, other medications and genetics all shift that, which is why every published figure is a range.
Hydration — but not the way people hope
Drinking large volumes of water dilutes urine and lowers metabolite concentration, but laboratories test specimen validity and can flag a diluted sample as invalid. It does not remove anything from the body.
The route and formulation
Extended-release formulations, and drugs that are metabolized into other detectable drugs, can produce a different pattern than a single immediate dose of the same substance.
Screening Tests Are Presumptive, Not Final
Most workplace and clinical drug screens begin with an immunoassay, which uses antibodies to flag whether a class of compounds appears to be present above a cutoff. That result is presumptive. Confirmatory testing by mass spectrometry — GC-MS or LC-MS/MS — identifies the specific compound and is what a positive screen should be verified with before any conclusion is drawn.
This distinction matters because immunoassays can cross-react. The American College of Medical Toxicology’s position statement on interpreting urine opiate and opioid tests describes how opiate immunoassays vary in what they detect, how poppy seed ingestion can produce a positive opiate result, and why the panels are frequently misread. It also notes that many synthetic and semi-synthetic opioids are poorly detected, or not detected at all, by a standard opiate immunoassay — a negative result is not proof of no use.
If a result carries consequences — employment, custody, treatment, or legal exposure — the right question is which assay was used, what its cutoff was, and whether confirmatory testing was performed.
Why We Only Show Urine and Half-Life
Urine is the matrix with published, drug-by-drug reference tables behind it, and plasma half-life is published alongside it. Blood and saliva windows are widely repeated across the web as precise hour counts, but those specific numbers usually cannot be traced back to a clinical reference table for each individual drug. Rather than repeat figures we cannot attribute, we describe what those tests actually do below.
Saliva (Oral Fluid) Testing
Oral fluid testing detects recent use. Because it largely measures the parent drug still circulating rather than metabolites the liver has already processed, its window is generally much shorter than urine — typically a matter of hours to a small number of days, depending on the drug and the assay cutoff. Oral fluid was added to the federal Mandatory Guidelines for Federal Workplace Drug Testing Programs, published in the Federal Register on October 12, 2023, which sets the analytes and cutoff concentrations federal programs use. We do not publish per-drug hour counts for saliva because those guidelines set cutoffs, not detection windows.
Hair Testing
Hair testing is not a window in the same sense. A standard head-hair sample of about 1.5 inches (3.8 cm) reflects roughly the most recent 90 days of growth, and because hair has to grow out from the scalp before it can be collected, very recent use may not yet be captured in the sample. Hair testing is also not part of the finalized federal workplace guidelines: the Department of Health and Human Services published proposed hair guidelines in the Federal Register on September 10, 2020, and they remain a proposal rather than a final rule.
Detection Windows Are Not the Same as Withdrawal
A substance clearing a test does not mean the body has finished adjusting. Alcohol and benzodiazepine withdrawal in particular can become medically dangerous, and both can require supervised detox. If you are stopping either one after regular use, that is a medical question, not a testing question.
Frequently Asked Questions
How long do drugs stay in your urine?
It depends on the drug. StatPearls' urine detection table lists roughly 1 to 3 days for cocaine and casual cannabis use, 2 to 4 days for methamphetamine, and up to 4 to 6 weeks for chronic cannabis use. These are published reference ranges rather than predictions, and the actual result depends on dose, metabolism, hydration, the assay used, and its cutoff concentration.
What is the difference between a detection window and a half-life?
A half-life is the time it takes for the concentration of a drug in blood plasma to fall by half. A detection window is how long a laboratory assay can still identify the drug or its metabolite in a sample, which is usually far longer than the half-life because tests target metabolites the body excretes slowly.
Can anything speed up how fast a drug leaves your system?
No reliable method exists. Water, exercise, detox drinks, and supplements do not change how quickly the liver metabolizes a substance or how quickly its metabolites are excreted. Drinking large amounts of water before a test dilutes the sample, which laboratories screen for and can flag as an invalid specimen.
Why does chronic cannabis use show up so much longer?
THC's metabolite, THC-COOH, is stored in fat and released slowly over time. StatPearls lists 5 to 10 days for daily use and 4 to 6 weeks for chronic use, compared with 1 to 3 days for casual use — the widest gap between casual and chronic use of any commonly screened drug.
Does clearing a drug test mean withdrawal is over?
No. Testing and withdrawal are separate processes. A substance can clear a urine screen while the body is still adjusting, and in the case of alcohol and benzodiazepines, withdrawal can become medically dangerous and may require supervised detox. If you are stopping either after regular use, treat it as a medical question.
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