How Long Do Drugs Stay in Your System? (Detection Chart)?
Evidence-based answer reviewed against SAMHSA cutoffs and FDA assay documentation · Updated August 2026
Quick answer: Detection windows depend on three variables: the drug's chemistry, the specimen tested, and your usage pattern. This chart consolidates consensus ranges from FDA device inserts and SAMHSA guidance — individual results vary.
Master detection table
| Substance | Urine | Saliva (swab) | Hair | Blood |
|---|---|---|---|---|
| THC | about 3 days | 24 hours | up to 90 days (standard head-hair window) | 12–24 hours |
| Alcohol | ethanol itself: roughly 6–12 hours | 6–12 hours | EtG segment analysis covers roughly the past 90 days | roughly 6–12 hours, tracking BAC decline (~0.015%/hr average) |
| Cocaine | 2–3 days | 1–2 days | up to 90 days | 12–48 hours |
| Meth | 3–5 days | 1–4 days | up to 90 days | 1–3 days |
| Amphetamines | 1–3 days | 1–2 days (20–50 hours) | up to 90 days | ~12–24 hours |
| MDMA | 1–3 days | 1–2 days | up to 90 days | ~12–24 hours |
| Opiates | ~1–2 days (6-MAM vanishes within ~8–22 hours; total morphine window 1–3 days) | 1–2 days | up to 90 days | ~12–24 hours |
| Oxycodone | 1–3 days | 1–2 days | up to 90 days | ~24 hours |
| Hydrocodone | 1–4 days | 1–2 days | up to 90 days | ~24 hours |
| Benzos | alprazolam/lorazepam: ~2–4 days | 1–3 days | up to 90 days | 1–2 days |
| Buprenorphine | 3–6 days | 1–4 days on specialized assays | up to 90 days (specialized) | ~2–4 days |
| Methadone | 2–4 days | 1–3 days | up to 90 days | ~2–3 days |
| PCP | 3–7 days | 1–3 days | up to 90 days | 1–3 days |
| Barbs | 1–3 days (secobarbital) | ~1–3 days | up to 90 days | 1–4 days (phenobarbital longer) |
| Fentanyl | 1–3 days (up to ~5 in heavy exposure) | 1–2 days | up to 90 days (specialized) | ~12–48 hours |
| Kratom | ~3 days | ~1–3 days (specialized) | up to 90 days (rarely offered) | ~2–3 days |
| Nicotine | 3–4 days | 1–4 days (cotinine) | 1–3 months | 1–3 days (cotinine up to 10) |
| Shrooms | roughly 24 hours; up to 3 days in heavier-use cases on specialized assays | ~24 hours on specialized tests | detectable in theory for 90 days, but psilocybin hair testing is rarely offered commercially | ~24 hours |
| LSD | ~1 day (8–24 h typical; 2–5 days mega-dose edge cases) | ~8–12 hours (research) | 90 days; commercial availability rare | ~12 hours |
| Ketamine | 1–3 days (norketamine tail) | ~1 day | up to 90 days (specialized) | ~12–24 hours |
Why urine windows stretch for weed but not coke
THC-COOH deposits into adipose tissue and leaches back over weeks. Cocaine's benzoylecgonine stays water-soluble and renal-clears within days. Fat solubility — not dose size — explains nearly all window differences between drugs.
Hair tests read a different clock entirely
Hair captures drug molecules entering the growing shaft via the bloodstream, preserving roughly a 90-day history at standard head-hair lengths (1.5 inches). Body hair grows slower and can extend the lookback further.
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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)