How Long Does Alcohol Stay in Your System?
Updated March 2026 · 8 min read
The short answer: it depends on the test. A standard blood test picks up alcohol for about 6 hours. A breathalyzer extends that window to 12-24 hours. A urine EtG test can flag you for up to 80 hours. And a hair follicle test? That looks back 90 days.
Your body breaks down alcohol at a fairly predictable rate — roughly one standard drink per hour, or about 0.015% BAC per hour. But "how long it stays" really depends on what's being measured and which test is used. Let's walk through each one.
Blood: Up to 6 Hours
A blood test is the gold standard for measuring current intoxication. It directly measures the concentration of ethanol circulating in your bloodstream — what we call BAC (Blood Alcohol Content).
For most people, alcohol becomes detectable in blood within 15-45 minutes of the first sip. Peak blood alcohol levels typically occur 30 to 90 minutes after finishing a drink, depending on stomach contents and drinking speed.
The liver metabolizes ethanol at a steady pace. Once your BAC drops to 0.00%, a standard blood test won't find it. For a person who reaches a BAC of 0.08%, that means roughly 5-6 hours until blood alcohol is undetectable.
Blood tests are commonly used in hospitals, DUI investigations, and workplace incidents. They're accurate but only reflect your BAC at the moment the sample is drawn.
Want to estimate your current BAC? Try our BAC Calculator — enter your drinks, weight, and time to get a rough estimate.
Breath: 12-24 Hours
Breathalyzers work differently from blood tests. They measure alcohol vapor in the air you exhale, which correlates closely with blood alcohol levels. Law enforcement relies heavily on roadside breath tests because they're fast, non-invasive, and reasonably accurate.
The detection window for breath tests runs longer than blood because trace amounts of alcohol linger in the lungs and airways even after blood levels drop. For moderate drinking (3-4 standard drinks), alcohol is typically detectable by breathalyzer for 12-16 hours.
Heavy drinking pushes that window to 24 hours or more. This is why someone who drinks heavily on a Saturday night might still blow a positive result on Sunday morning — even if they feel relatively sober.
Factors that extend the breath detection window include the total amount consumed, whether you drank on an empty stomach, and individual variation in how your body processes alcohol.
Urine: 12-80 Hours
There are two types of urine alcohol tests, and the difference matters considerably.
A standard urine test detects ethanol directly. Its window is relatively short — about 12 to 24 hours after drinking, roughly similar to breath tests. These are less common today because of the second option.
The EtG (Ethyl Glucuronide) test is far more sensitive. Instead of looking for alcohol itself, it detects a metabolite — a byproduct your body creates while breaking down ethanol. EtG lingers in urine long after the alcohol is gone.
Helander and Böttcher's study in Alcohol and Alcoholism measured a median EtG detection window of 78 hours after heavy drinking — which means someone who ties one on Friday night could still test positive Monday morning, a gap that makes weekend drinking nearly impossible to hide from a probation officer or court-ordered screen.
Courts, probation programs, and some employers favor EtG testing specifically because of this extended detection window. It answers the question "did this person drink recently?" rather than "are they drunk right now?"
One important note: EtG tests are sensitive enough to flag incidental alcohol exposure — certain hand sanitizers, mouthwashes, and even some foods can occasionally cause a low-level positive result.
Hair: Up to 90 Days
Hair follicle testing provides the longest detection window of any alcohol test. It can identify alcohol use from the past 90 days by analyzing two markers: EtG (Ethyl Glucuronide) and FAEE (Fatty Acid Ethyl Esters).
When your body metabolizes alcohol, these markers enter the bloodstream and get deposited into hair follicles as new hair grows. A standard hair test examines the 1.5 inches of hair closest to the scalp, which represents approximately three months of growth.
Hair tests cannot pinpoint exactly when drinking occurred or how much was consumed in a single session. They're primarily used to establish a pattern of use — distinguishing between someone who rarely drinks and someone who drinks regularly.
Pre-employment screenings, custody cases, and certain professional licensing boards sometimes request hair follicle alcohol testing. It's harder to cheat than urine testing and provides a much broader look at drinking history.
Saliva: 1-5 Days
Saliva testing occupies a middle ground between blood and urine tests. Oral fluid tests can detect alcohol for 1 to 5 days after consumption, depending on the type of test and the amount of alcohol consumed.
Basic saliva alcohol tests work similarly to breathalyzers — they detect ethanol directly and have a short window of about 12-24 hours. However, newer EtG saliva panels extend that window considerably, up to 5 days in some cases.
Saliva tests are gaining popularity for workplace and roadside testing because sample collection is easy, non-invasive, and hard to tamper with. The sample is collected right in front of the tester.
Detection Windows Summary
| Test Type | Detection Window | What It Measures |
|---|---|---|
| Blood | Up to 6 hours | Ethanol in bloodstream (BAC) |
| Breath | 12-24 hours | Alcohol vapor in exhaled air |
| Urine (standard) | 12-24 hours | Ethanol in urine |
| Urine (EtG) | 24-80 hours | EtG metabolite |
| Saliva | 1-5 days | Ethanol or EtG in oral fluid |
| Hair | Up to 90 days | EtG and FAEE markers in hair |
Factors That Affect How Long Alcohol Stays in Your System
While the liver clears alcohol at a roughly fixed rate (about 0.015% BAC per hour for most adults — use our sober calculator to map your timeline), several factors influence how high your BAC gets in the first place — and that directly determines how long it takes to return to zero.
Body Weight and Composition
Larger individuals generally have more body water, which dilutes alcohol and produces a lower peak BAC from the same number of drinks. A 220-pound person drinking three beers will reach a meaningfully lower BAC than a 130-pound person drinking the same amount.
Body fat percentage matters too. Fat tissue contains very little water, so someone with a higher body fat percentage will have less water available to dilute alcohol — resulting in a higher BAC even at the same weight.
Biological Sex
A 2023 body-composition study in Nutrients (PMC10265208) measured total body water at about 55% for adult women versus 60-62% for men — a gap driven primarily by differences in muscle mass and fat distribution. That means the same number of drinks produces a higher BAC in women simply because there is less water to dilute the ethanol. On top of that, Frezza and colleagues found in a landmark 1990 New England Journal of Medicine study that women produce significantly less gastric alcohol dehydrogenase, the stomach enzyme that starts breaking down alcohol before it even hits the bloodstream.
Food in the Stomach
Drinking on a full stomach slows absorption substantially. Food — particularly protein and fat — keeps the pyloric valve closed longer, delaying alcohol's passage to the small intestine where most absorption happens. Lower peak BAC means less total time until you hit zero.
Liver Health
Your liver does about 90% of alcohol metabolism. Any condition that impairs liver function — fatty liver disease, hepatitis, cirrhosis — directly slows the elimination rate. Someone with liver damage may metabolize alcohol significantly slower than the average 0.015% per hour.
Medications
Certain medications compete with alcohol for the same liver enzymes, potentially slowing metabolism. Acetaminophen (Tylenol), some antibiotics, antidepressants, and anti-anxiety medications can all interact with alcohol metabolism. Some medications also amplify alcohol's effects without changing BAC — making you feel more impaired at a lower blood alcohol level.
Age
Alcohol metabolism generally slows with age. Older adults tend to have less body water, reduced liver function, and often take medications that interact with alcohol. A 65-year-old will typically clear alcohol from their system more slowly than a 25-year-old of similar size and health.
Drinking Speed
How fast you drink directly impacts peak BAC. Four drinks consumed in one hour produce a substantially higher BAC than the same four drinks spread across four hours. Higher peak BAC means more time until your system clears completely — and a worse hangover the next morning.
Common Myths About Sobering Up
A few popular beliefs about speeding up alcohol elimination deserve direct correction.
Coffee does not sober you up. Temple University researchers Gulick and Gould tested this in Behavioral Neuroscience and found caffeine masks drowsiness without reducing impairment — your reaction time stays wrecked, but you feel sharper, which is arguably worse because that false confidence is what gets people behind the wheel.
Cold showers don't help. A cold shower might shock you into feeling more alert temporarily, but it has zero effect on how fast your liver processes alcohol.
Exercising doesn't speed up elimination. While a small amount of alcohol leaves through sweat, the quantity is negligible. The vast majority of alcohol is metabolized by the liver at a fixed rate that exercise cannot change.
Eating after drinking doesn't lower your BAC. Food slows absorption when eaten before or during drinking. Once alcohol is already in your bloodstream, eating does nothing to speed up its removal.
Time is the only thing that works. Your liver processes alcohol at about 0.015% BAC per hour. Nothing accelerates this process. The only reliable way to reduce your BAC is to wait.
When to Seek Medical Attention
Alcohol poisoning is a medical emergency. If someone is unconscious, breathing slowly (fewer than 8 breaths per minute), has pale or bluish skin, is vomiting while unconscious, or has had a seizure — call 911 immediately. Do not wait for them to "sleep it off."
If you have concerns about your drinking patterns, the SAMHSA National Helpline provides free, confidential help 24 hours a day: 1-800-662-4357.