Most people search “how long do drugs stay in your system?” for a simple answer they can hold onto. They’re facing a test for work or court, trying to understand a confusing result, or worrying about someone they love and looking for clarity.

The tricky part is that “in your system” can mean different things depending on the test. A substance might be gone from the part of the body that causes impairment, but still show up as leftover metabolites on a urine screen days later. And two people can use the same drug and get different detection windows based on factors like use history, metabolism, and the lab cutoff.

In this guide, we’ll explain what “in your system” actually refers to, what changes the timeline, and the typical urine test detection ranges for common substances. We’ll also clear up a common misconception: a drug test can show recent exposure, but it can’t diagnose addiction—or prove someone is “clean.”

What “In Your System” Actually Means

“In your system” can sound like a simple, medical phrase, but most people are really asking a testing question: how long could a drug test still pick something up? And that’s where things get confusing fast.

• The test type (urine vs saliva vs hair)
• How often and how much the person used
• The drug itself and how it’s metabolized
• Individual factors like body composition, liver/kidney function, and metabolism 

Also important: a positive drug test can’t diagnose addiction; it only indicates recent exposure to a substance (or its metabolites).

Quick Guide: How Long Each Drug Can Show Up On a Urine Test

These timelines are typical ranges, not guarantees. Drug detection windows vary by lab methods and cutoffs, and by the person’s use pattern. The biggest factor is usually how often someone uses.

• Alcohol (EtG): 1–4 days
• Marijuana (THC): 1–30+ days (can be longer with frequent use)
• Cocaine: 1–3 days
• Meth: 2–5 days
• Amphetamines (like Adderall): 2–5 days
• MDMA (ecstasy/molly): 2–4 days
• PCP: 3–7 days (can be longer with heavy use)
• Heroin: 1–3 days
• Morphine: 2–3 days
• Codeine: 1–3 days
• Hydrocodone: 2–4 days
• Oxycodone: 2–4 days
• Fentanyl: 2–4 days (can be longer depending on use)
• Benzos (like Xanax, Ativan, Valium): 3–7 days (often longer with regular use)
• Methadone: 7–14 days
• Buprenorphine (Suboxone): 7–14 days

Not Everyone’s the Same

Just like with addiction in general, not everyone’s body will process addictive substances the same. Body weight, genetics, individual health, and so many other factors all come into play in how long these drugs stay in your system.

And on top of that, the body metabolizes different drugs and alcohol in different ways, too. As a result, each drug will stay in your body for a different length of time. The drugs are detectable in your urine, blood, oral fluids, and hair. 

What Are the Types of Drug Tests?

Different tests look for different markers. Some look for the drug itself. Others look for the byproducts your body leaves behind after it breaks the drug down. Those byproducts can hang around longer than the effects you’d actually feel, which is why someone can feel totally normal and still test positive.

Urine drug tests (most common)

Urine tests usually detect recent use, but the exact window depends on the drug and how often someone uses it. his is where use patterns matter most. For example, someone who uses occasionally may test negative quickly, while frequent use can keep a substance detectable much longer. 

Cannabis is a common example: it might show up for a few days after one-time use, but it can stick around for weeks if someone uses marijuana regularly.

Saliva drug tests (oral fluid)

Saliva tests tend to reflect very recent use. They’re often used when the goal is to capture a shorter detection window, like use within the past day or two.

Hair follicle drug tests (longer-term pattern)

Hair tests are less about “what happened yesterday” and more about ongoing use over time. They can help show patterns across weeks, which is why they’re sometimes used in high-accountability settings.

Blood drug tests (very recent use)

Blood tests typically pick up the shortest window and are more common in medical or impairment-related situations. They can show very recent use, but they’re not the go-to option for most routine screenings.

What Drug Stays in Your System the Longest?

The drug that tends to stay in your system the longest depends on the type of test, but THC is usually the longest-lasting on a urine test, which is the most common drug test. With frequent or heavy use, urine tests can detect THC metabolites for about 1–2 months.

If you’re talking about the longest detection window overall, hair testing can detect many drugs for much longer—often up to about 3 months (because it reflects longer-term use patterns, not just recent use).

Does a negative drug test mean someone is “clean”?

A negative drug test can be reassuring, but it does not automatically mean someone is substance-free or “in the clear.” It only tells you what the test did or didn’t detect during a specific window of time.

A few reasons a test might come back negative even if there’s a real problem:

• The timing didn’t line up. Some drugs leave the body quickly, so a test taken days later may miss use that still matters.
• The test didn’t include the right substance. Many standard panels don’t catch everything, and some drugs require a specific test.
• The person used in a way that’s harder to detect. Small amounts, spaced-out use, or switching substances can affect results.
• A long-term pattern can exist even with negative tests. Dependence is about behavior and impact, not one single result.

If you’re trying to understand whether someone has a problem, the clearer signs are usually around patterns: needing more to get the same effect, using to cope, hiding it, struggling to stop, withdrawal symptoms, and ongoing fallout in relationships, work, or health.

What Affects How Long Drugs Stay in Your System?

Detection timelines vary because the body is not a stopwatch. Two people can use the same substance and see different results, especially if their patterns of use and overall health look different. These factors tend to build on each other, which is why “how long” is rarely one simple number.

How often someone uses

Frequency is one of the biggest reasons detection windows stretch. A one-time use leaves the body faster than repeated use because the substance and its byproducts have less time to build up. With ongoing use, the body is often processing a new dose before it has fully cleared the last one, which extends how long it can show up on a test.

How much was used and how strong it was

Amount matters, and so does potency. Higher doses usually create more byproducts for the body to clear, and that can lengthen detection. This is also why someone can be surprised by a positive test even if they feel like they did not use “that much.” What feels small to them may still be enough to register, depending on the substance and the test.

The type of drug and how the body processes it

Different substances leave the body at different speeds. Some break down quickly and leave a shorter detection window. Others leave byproducts that linger. This is one reason cannabis and certain long-acting medications are often detected longer than drugs that clear more quickl

If you’re comparing timelines across substances, it helps to remember you’re not comparing apples to apples. Each drug breaks down differently, so the “how long” can vary a lot even with similar use.

Body composition and metabolism

The body’s baseline plays a role in how substances move through it. Metabolism affects how quickly the body breaks a drug down. Body composition can affect where certain substances are stored and how long they linger. This is part of why two people can use the same drug in similar amounts and have different detection windows, even if they took it around the same time.

Overall health, especially liver and kidney function

The liver and kidneys do much of the work of processing and clearing substances. When someone is run down, dehydrated, or dealing with health issues, clearance can slow. This can also be relevant for people with longer histories of use, since substance use can affect sleep, nutrition, and overall stability, all of which influence how the body functions day to day.

The test type and the lab cutoff

The test itself shapes the answer. Urine, saliva, blood, and hair do not look at the same window of time. Even within the same test type, labs can use different cutoffs, which affects what counts as “positive.” This is why timing questions can feel confusing. A result can change based on when the test happens, what it is designed to detect, and how sensitive it is.

How Long Do Drugs Stay in Your System for a Swab Test?

A swab test usually means an oral swab, also called a saliva test. These tests tend to look for more recent use than urine tests, so the detection window is often shorter.

In many cases, drugs show up on a swab test for about 1 to 3 days, though some substances can fall outside that range depending on the person, the amount used, and the type of test.

Here’s how it commonly plays out in real life.

• One-time or occasional use is more likely to show up for a shorter window, sometimes closer to a day.
• Frequent or heavy use can extend the window, especially if use is ongoing or very recent.
• Smoking or vaping can sometimes increase what’s detectable in the mouth shortly after use.
• THC is unpredictable on swab tests. Some people test negative quickly, while others can test positive longer, depending on use pattern and how the test is designed.

If you’re trying to make sense of a swab result, it helps to remember what it’s best at. Swab tests are mainly designed to catch recent use, not long-term patterns. If the bigger concern is dependency or relapse risk, behavior and stability usually tell a clearer story than one test result.

Find Real Support for Substance Abuse

Changing your relationship with substances can feel overwhelming, especially if the focus has been on timelines and tests instead of what’s really going on underneath. If you’re starting to wonder whether your use has crossed a line, or you’re worried about someone you love, you do not have to sort it out alone.

At Northpoint Recovery, we help people understand their substance use, stabilize safely when needed, and build a plan that supports lasting change. Contact us today to talk through what’s happening and explore treatment options that fit your situation.