How Long Do Drugs Stay in Your System? Complete Detection Times by Substance
The amount of time a drug remains detectable depends on the substance, the test type, your metabolism, frequency of use, and a host of other factors. We compiled the most up-to-date detection windows from peer-reviewed toxicology literature, organized by substance and test method.
How Detection Windows Work
Drug detection windows are not fixed numbers, they depend on:
- Half-life of the drug: How quickly your body metabolizes and eliminates it
- Fat solubility: Drugs stored in fat tissue (THC, benzodiazepines) linger longer than water-soluble drugs
- Frequency of use: Chronic use builds up tissue stores that take longer to clear
- Individual metabolism: Liver function, body fat percentage, hydration, age
- Test cutoff concentration: Lower cutoff = longer detection window
The detection windows below represent the typical range for most people based on peer-reviewed toxicology studies. They are not guarantees.
Complete Detection Times Reference Table
| Substance | Urine | Blood | Saliva | Hair | Half-Life |
|---|---|---|---|---|---|
| Alcohol | 12-48 hours | 6-12 hours | 6-12 hours | Up to 90 days | 4-5 hours |
| THC (single use) | 3-5 days | 2-24 hours | 1-3 days | Up to 90 days | 20-36 hours |
| THC (chronic) | 14-45 days | 3-7 days | 1-29 days | Up to 90 days | 20-36 hours |
| THC (daily heavy) | 30-77 days | 7-14 days | Up to 30 days | Up to 90 days | 20-36 hours |
| Cocaine | 2-4 days | 12-24 hours | 12-48 hours | Up to 90 days | ~1 hour |
| Cocaine (chronic) | 5-10 days | 1-2 days | 1-3 days | Up to 90 days | ~1 hour |
| Heroin | 1-3 days | 6-12 hours | 6-24 hours | Up to 90 days | 2-6 minutes |
| Codeine | 2-4 days | 24 hours | 12-36 hours | Up to 90 days | 2-4 hours |
| Morphine | 2-4 days | 6-24 hours | 12-24 hours | Up to 90 days | 2-3 hours |
| Fentanyl | 24-72 hours | 6-12 hours | 6-24 hours | Up to 90 days | 3-7 hours |
| Methamphetamine | 3-6 days | 12-24 hours | 12-72 hours | Up to 90 days | 9-24 hours |
| Amphetamine | 2-4 days | 12-24 hours | 12-48 hours | Up to 90 days | 9-14 hours |
| MDMA | 2-4 days | 12-24 hours | 12-24 hours | Up to 90 days | 6-9 hours |
| LSD | 2-4 days | 6-12 hours | 2-6 hours | Up to 90 days | 3-5 hours |
| Psilocybin | 15-24 hours | 6-12 hours | 6-12 hours | Up to 90 days | ~2 hours |
| Ketamine | 2-5 days | 6-24 hours | 12-24 hours | Up to 90 days | 2-3 hours |
| GHB | 6-12 hours | 4-6 hours | 4-6 hours | Up to 90 days | 30-50 minutes |
| Benzodiazepines (short) | 3-5 days | 12-24 hours | 1-3 days | Up to 90 days | 6-24 hours |
| Benzodiazepines (long) | 14-30 days | 3-7 days | 3-7 days | Up to 90 days | 20-100 hours |
| Xylazine | 2-4 days | 12-24 hours | 12-24 hours | Up to 90 days | 6-8 hours |
Key Takeaways by Drug Class
Cannabis (THC)
THC is the most detectable drug because it is fat-soluble. It accumulates in adipose tissue and is released slowly over time. Occasional users may test positive for 3-7 days. Daily heavy users can test positive for 30-77 days after cessation, one study found detectable THC-COOH (the primary metabolite) for up to 77 days after last use.
Important: CBD products that contain trace THC (up to 0.3% in federally legal hemp) generally do NOT produce positive drug tests. However, full-spectrum CBD products with higher THC levels can cause positives, especially with daily use.
Opioids
Heroin has the shortest detection window of any opioid, its half-life is measured in minutes. However, its metabolite (6-MAM) and further metabolites (morphine, codeine) are detectable for 1-3 days in urine.
Fentanyl is detectable for 24-72 hours in urine. Standard opioid immunoassay tests may NOT detect fentanyl, it requires a specific fentanyl test strip or a customized GC-MS method. This is why many overdose deaths involve fentanyl-positive users who screened negative on a standard opioid test.
Stimulants
Methamphetamine remains detectable longer than amphetamine due to its slightly longer half-life and higher fat solubility. Both can be detected in urine for 3-6 days after moderate use.
MDMA is detectable for 2-4 days. It can cause false positives for amphetamine on some immunoassay screens due to structural similarity, GC-MS confirmation is required for definitive identification.
Psychedelics
Psilocybin (magic mushrooms) has one of the shortest detection windows, typically under 24 hours in urine. The body converts psilocybin to psilocin, which is rapidly eliminated.
LSD is detectable for only 2-4 days in urine and 6-12 hours in blood. Most standard drug panels do NOT test for LSD, but specialized tests exist for probation, military, and certain employment contexts.
Benzodiazepines
Detection windows vary enormously by half-life:
- Short-acting (alprazolam/Xanax, triazolam): 3-5 days in urine
- Long-acting (diazepam/Valium, chlordiazepoxide): 14-30 days in urine
The metabolites of long-acting benzodiazepines accumulate with regular use and can persist for weeks after the last dose.
Factors That Extend Detection Windows
- Body fat percentage: Higher body fat = longer detection for fat-soluble drugs (THC, benzodiazepines)
- Frequency of use: Regular/chronic use leads to tissue accumulation
- Liver function: Impaired liver function slows metabolism
- Kidney function: Impaired kidney function slows elimination
- Hydration: Dehydration concentrates urine and may increase detection likelihood
- Age: Older adults metabolize drugs more slowly
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Factors That Shorten Detection Windows
- Hydration: Well-hydrated individuals produce more dilute urine (but excessive water intake before a test can trigger a "dilute" result, which may be treated as a positive by some programs)
- Exercise: Increases metabolism and fat mobilization, but may temporarily increase THC metabolite levels as stored THC is released from fat cells
- Metabolic rate: Faster metabolism = faster clearance
Common Drug Testing Panels
| Panel | Drugs Tested | Typical Use |
|---|---|---|
| 5-Panel | THC, Cocaine, Opiates, PCP, Amphetamines | Employment (standard) |
| 8-Panel | Same + MDMA, Benzodiazepines, Barbiturates | Safety-sensitive positions |
| 10-Panel | Same + Methadone, Propoxyphene, Quaaludes | Clinical, probation |
| 12-Panel | Same + Buprenorphine, Oxycodone | Pain management |
| 16-Panel | Extended opiate panel including fentanyl | Opioid treatment programs |
Note: This article is for educational purposes only. We are not medical professionals. Detection windows vary by individual. Always consult a qualified healthcare provider for specific advice about drug testing.
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