How long “dope” stays in your system depends on which substance you mean, since the term is used for marijuana, heroin, and methamphetamine depending on where you live. For a standard urine test, marijuana is detectable for 3 to 30+ days, heroin for 2 to 3 days, and methamphetamine for 1 to 5 days. The exact window varies with how often you use, your body composition, and the type of test.
Marijuana Detection Times
Marijuana has the widest detection range of any common drug because THC, its active compound, dissolves into fat tissue throughout your body. After you use it, THC moves quickly from your blood into fat, the liver, lungs, and brain. It then slowly leaks back out of those fat stores into your bloodstream, where your liver breaks it down into a byproduct that eventually leaves through your urine. That byproduct has a half-life of roughly 30 hours in occasional users, meaning it takes about 30 hours for your body to clear just half of it. In people with longer or heavier use patterns, the half-life can stretch to 45 or even 60 hours.
This is why frequency of use matters so much. Approximate urine detection windows look like this:
- Single use (one session): about 3 days
- Moderate use (four times a week): 5 to 7 days
- Daily use: 10 to 15 days
- Heavy daily use (multiple sessions per day): 30 days or more
Body fat percentage plays a real role here. Someone with more body fat has more storage space for THC, so it takes longer to fully clear. Metabolism, hydration, and how much you used each session also shift the window, but frequency and body composition are the two biggest factors.
In blood and saliva, marijuana clears much faster. Saliva tests can pick up THC for up to about 3 days after use. Blood concentrations drop within hours, which is why blood tests primarily reflect very recent use.
Heroin and Opioid Detection Times
Heroin itself has a half-life of just a few minutes. Your body converts it almost immediately into a short-lived marker called 6-MAM, which is the only metabolite that conclusively proves heroin use rather than use of another opiate. The problem for detection is that 6-MAM is only present in urine for about 8 hours after use. After that, it breaks down further into morphine, which is indistinguishable from morphine exposure from other sources.
For a standard urine drug screen, opiates from heroin use are generally detectable for 2 to 3 days after your last dose. In oral fluid (saliva), the window is similar or slightly shorter. Federal workplace tests now also screen for fentanyl separately, with an extremely sensitive cutoff, reflecting how common fentanyl contamination has become in the drug supply.
Because heroin clears so quickly compared to marijuana, the detection window is relatively narrow. But it’s worth knowing that many drug panels test broadly for opioids, so prescription painkillers, morphine, and heroin metabolites can all trigger the same initial screen. Confirmatory testing then identifies the specific substance.
Methamphetamine Detection Times
Methamphetamine falls in the middle of the detection spectrum. In urine, it’s typically detectable for 1 to 5 days after use. Saliva tests pick it up for 1 to 3 days. These windows apply to standard recreational doses. Binge use or very high doses can push detection slightly longer, but meth doesn’t accumulate in fat the way THC does, so the tail-off is much more predictable.
Amphetamine, which is both a standalone drug and a natural breakdown product of methamphetamine, has a nearly identical detection window of 1 to 5 days in urine. If you use meth, both methamphetamine and amphetamine will show up on a panel.
Cocaine Detection Times
Since “dope” occasionally refers to cocaine in some regions, it’s worth covering. Cocaine’s primary byproduct is detectable in urine for 1 to 4 days after use. Saliva tests catch it for 1 to 3 days. Heavy, repeated use over a short period can extend the urine window somewhat, but cocaine generally clears faster than most other substances besides alcohol.
How Different Test Types Compare
The type of test changes the detection window dramatically. Urine testing is the most common for employment and legal screens. It catches drug byproducts that concentrate in urine over days, making it a good tool for detecting use within the past week or so for most substances.
Saliva testing is increasingly used for roadside and workplace screening. It detects the parent drug rather than byproducts, so it reflects more recent use, typically within the past 1 to 3 days. Blood tests have the shortest window and mostly confirm very recent or current impairment.
Hair testing is the outlier. It provides up to a 90-day detection window because drug metabolites get incorporated into the hair shaft as it grows. Hair tests tend to produce more positive results than urine tests simply because of that extended lookback period. A standard hair sample is 1.5 inches, representing roughly three months of growth. Hair testing is less common for routine screening but is used in some legal, custody, and high-security employment contexts.
What Affects Your Personal Timeline
Detection times published in charts are population averages. Your actual clearance time is shaped by several overlapping factors. Body fat matters most for THC, since it’s fat-soluble. A lean person who uses marijuana occasionally will clear it far faster than a heavier person who uses at the same frequency. For water-soluble drugs like methamphetamine and cocaine, body fat matters less, but kidney function and hydration still play a role.
Metabolic rate is the other major variable. People with faster metabolisms process and excrete drug byproducts more quickly. Age, physical activity, liver health, and genetics all feed into metabolic speed. Dose size and route of administration also matter: smoking or injecting delivers a faster, higher peak that may clear sooner than oral ingestion of the same substance, but the total amount in your system is what ultimately determines how long it lingers.
Urine concentration at the time of the test can tip results either way. A very dilute sample may fall below the testing threshold even if byproducts are present, while a concentrated sample first thing in the morning may register positive when an afternoon sample would not. Federal workplace tests use a standard threshold for marijuana metabolites of 50 nanograms per milliliter on the initial screen and 15 on the confirmatory test, so there is a defined line your sample either crosses or doesn’t.
Quick Reference by Substance
- Marijuana: Urine 3 to 30+ days (depends heavily on frequency); saliva up to 3 days; hair up to 90 days
- Heroin/opiates: Urine 2 to 3 days; saliva 1 to 3 days; hair up to 90 days
- Methamphetamine: Urine 1 to 5 days; saliva 1 to 3 days; hair up to 90 days
- Cocaine: Urine 1 to 4 days; saliva 1 to 3 days; hair up to 90 days