Alcohol leaves your body at a fairly constant rate of about one standard drink per hour. Your liver does nearly all the work, breaking down alcohol at roughly 0.015% BAC per hour regardless of how much you’ve had. But “how long it stays” depends on what you’re measuring: the buzz, the blood alcohol level, or what a drug test can pick up days or even months later.
How Your Body Processes Alcohol
Your liver handles over 90% of alcohol elimination. It uses two enzymes working in sequence. The first converts alcohol into acetaldehyde, a toxic compound and known carcinogen. The second quickly breaks acetaldehyde down into acetate, which your body then converts to carbon dioxide and water for easy removal. This two-step process is why your liver takes the biggest hit from heavy drinking: it’s the organ doing the chemical heavy lifting.
The critical thing to understand is that this process runs at a nearly fixed speed. Unlike caffeine or many medications, alcohol doesn’t clear faster just because there’s more of it in your system. Your liver processes about 15 mg/dL per hour, which translates to roughly 0.015% BAC per hour. That’s approximately one standard drink (a 12-oz beer, a 5-oz glass of wine, or a 1.5-oz shot of liquor) every 60 minutes. If you’ve had four drinks, expect it to take around four hours for your blood alcohol to return to zero, assuming you stopped drinking after the last one.
Detection Windows by Test Type
The answer to “how long does alcohol stay in your system” changes dramatically depending on the type of test.
- Blood: A standard blood alcohol test can detect alcohol for up to 12 hours after your last drink.
- Breath: A breathalyzer can pick up alcohol for 12 to 24 hours, depending on how much you consumed.
- Saliva: Oral fluid tests detect alcohol for up to 24 hours.
- Urine (standard): A traditional urine test works within a similar window to blood, roughly 12 to 24 hours.
- Urine (EtG): Advanced urine tests look for a metabolic byproduct called EtG. After a few drinks, EtG can show up for 48 hours. After heavier drinking, it can persist 72 hours or longer.
- Hair: Hair follicle tests can detect alcohol markers for 3 to 6 months, though it takes several weeks after drinking for the markers to appear in the hair strand.
If you’re facing a workplace or legal test, the type matters enormously. EtG urine tests are common in court-ordered monitoring programs and use different sensitivity thresholds. A lower cutoff of 100 ng/mL catches even small amounts of drinking but can occasionally be triggered by alcohol-containing products like certain mouthwashes. A higher cutoff of 500 ng/mL is used when more certainty is needed, such as forensic cases.
Why Some People Process Alcohol Faster
While the average rate is one drink per hour, individual metabolism can range from about 0.01% to 0.02% BAC per hour. Several factors push you toward the slower or faster end of that range.
Biological sex plays a significant role. Women generally have less body water than men, which means alcohol is more concentrated in their blood after the same number of drinks. Research in animal models has shown that females can have 70% to 100% higher activity of the primary alcohol-processing enzyme in the liver compared to males, though this doesn’t necessarily translate to faster clearance in humans because of the body water difference and other variables. The net effect is that women typically reach higher BAC levels from fewer drinks and may feel the effects longer.
Body size and composition matter because alcohol distributes through body water. A larger person with more water volume will dilute the same amount of alcohol to a lower concentration, reaching a lower peak BAC and clearing it sooner.
Liver health is the most direct factor. Your liver’s ability to produce those two key enzymes determines your processing speed. Chronic heavy drinking, fatty liver disease, or cirrhosis can all slow alcohol metabolism significantly because the liver tissue responsible for producing those enzymes is damaged or scarred.
Genetics influence how much of each enzyme your body produces. Some people of East Asian descent carry gene variants that make the first enzyme work very fast but the second enzyme work slowly, causing a buildup of the toxic intermediate compound. This is what produces the facial flushing, nausea, and rapid heartbeat sometimes called “Asian flush.”
How Food Changes the Timeline
Eating before or while you drink doesn’t speed up metabolism, but it meaningfully slows absorption. Food in your stomach works two ways: it physically blocks alcohol from contacting your stomach lining, and it prevents alcohol from passing quickly into your small intestine, where most absorption happens. When alcohol gets held in your stomach longer, it enters your bloodstream more gradually, resulting in a lower peak BAC.
This is why drinking on an empty stomach hits harder and faster. You’ll reach a higher BAC more quickly, and although your liver still clears alcohol at the same fixed rate, a higher peak means more total time before you’re back to zero. A meal won’t sober you up, but it can meaningfully reduce how drunk you get and how long the effects last.
A Rough Timeline for Common Scenarios
Since your body clears about 0.015% BAC per hour, you can estimate your timeline with simple math. A 160-pound man who drinks three beers in an hour might reach a BAC around 0.06%. At 0.015% per hour, that takes about four hours to fully clear. The same three beers in a 130-pound woman could produce a BAC closer to 0.09%, taking roughly six hours to reach zero.
These are estimates, not guarantees. But they illustrate an important point: even moderate drinking can leave measurable alcohol in your blood well into the next morning. If you have four or five drinks finishing at midnight, you could still have a detectable BAC at 6 or 7 a.m. And an EtG urine test could flag that same evening’s drinking two or three days later.
Nothing accelerates the process. Coffee, cold showers, exercise, and water will not help your liver work faster. Time is the only thing that clears alcohol from your system. Staying hydrated and eating may help you feel better, but your liver is still running at the same fixed speed regardless of what you do.