Alcohol stays in your bloodstream for roughly 1 to 15 hours after your last drink if you’re a man, and up to 26 hours if you’re a woman, depending on how much you drank and your body weight. But “in your body” can mean different things depending on the test. Specialized urine tests can pick up traces of alcohol for up to 72 hours, and hair tests extend that window to 90 days.
How Your Body Processes Alcohol
Your liver does the heavy lifting. An enzyme called alcohol dehydrogenase breaks ethanol down into a toxic intermediate compound, which a second enzyme then converts into harmless acetate (essentially vinegar). Your body processes this at a remarkably steady pace: the average person clears about 0.015 to 0.020 points of blood alcohol concentration (BAC) per hour. That rate barely changes no matter how much coffee you drink or cold water you splash on your face.
To put that in practical terms: if you’re at the legal driving limit of 0.08 BAC, it takes roughly 4 to 5 hours to reach zero. The math is straightforward. At 0.015 per hour, a BAC of 0.08 takes just over five hours to clear. At 0.020 per hour, it takes four. Your actual rate falls somewhere in that range and stays fairly consistent from one drinking occasion to the next.
What Counts as One Drink
A standard drink in the United States contains about 14 grams of pure alcohol. That’s a 12-ounce beer at 5% alcohol, a 5-ounce glass of wine at 12%, or a 1.5-ounce shot of liquor at 40%. Many real-world drinks exceed these amounts. A craft IPA at 8% in a pint glass is closer to two standard drinks. A generous pour of wine can easily be seven or eight ounces. Underestimating your intake is one of the most common reasons people assume the alcohol has cleared when it hasn’t.
Detection Windows by Test Type
Different tests look for different things, and their detection windows vary widely.
- Blood test: Alcohol is detectable in blood for roughly the same window it takes your liver to process it. For a man who had 9 drinks, that can stretch to 15 hours. For a woman who had 9 drinks, it can take up to 26 hours to reach zero BAC.
- Breath test: A breathalyzer can detect alcohol for up to 24 hours after your last drink, though 12 hours is more typical for moderate consumption. The exact window depends on your metabolism, weight, age, and sex.
- Saliva test: Oral fluid tests detect alcohol for up to 24 hours.
- Standard urine test: A basic urine screen detects alcohol for roughly 12 to 24 hours.
- EtG urine test: This test doesn’t look for alcohol itself. It looks for a metabolic byproduct your body produces while processing alcohol. After a few drinks, this marker can show up in urine for up to 48 hours. After heavier drinking, it can remain detectable for 72 hours or longer.
- Hair test: Alcohol metabolites can be detected in hair for approximately 90 days, though hair testing is less common and primarily used in legal or forensic settings.
Why Women Process Alcohol More Slowly
Women consistently reach higher blood alcohol levels than men after the same number of drinks, and the alcohol stays in their system longer. Two biological factors drive this. First, women have less of the enzyme that breaks down alcohol in the stomach before it enters the bloodstream, a process called first-pass metabolism. This means more alcohol reaches the blood in the first place. Second, women generally have a lower volume of body water relative to their size, so the same amount of alcohol gets distributed into a smaller volume, producing a higher concentration.
The charts from the University of Arizona illustrate this clearly. A 140-pound woman who has 4 drinks needs roughly 8 hours to reach zero BAC, while a 180-pound man with the same number of drinks clears it in about 5 hours.
Food Makes a Significant Difference
Eating before or while you drink slows the rate at which alcohol reaches your small intestine, where most absorption happens. This doesn’t just delay the buzz. Research from Johns Hopkins University shows that consuming food while drinking increases the rate of alcohol elimination from the bloodstream by 25 to 45 percent. That’s a substantial difference. A meal rich in protein and fat is especially effective at slowing absorption, because it keeps the stomach’s exit valve partially closed for longer.
Drinking on an empty stomach does the opposite. Alcohol passes quickly into the small intestine, gets absorbed rapidly, and produces a sharper, higher peak BAC. That higher peak takes longer to clear.
How Regular Drinking Changes the Timeline
If you drink frequently, your liver adapts. Beyond the primary enzyme pathway, your liver has a backup system that kicks in when alcohol levels are high or when drinking is chronic. This backup system becomes more active with regular use, effectively increasing your liver’s processing capacity. Long-term heavy drinkers can metabolize alcohol faster than occasional drinkers as a result.
This adaptation is not a health advantage. The backup system generates more harmful byproducts called free radicals, which damage liver cells over time. It also changes how your liver handles other medications, potentially making them less effective or increasing their side effects. The fact that your body clears alcohol faster doesn’t mean it’s doing less damage.
Practical Timelines for Common Scenarios
Here’s what the math looks like for a few common situations, assuming an average elimination rate of 0.017 BAC per hour:
- Two drinks over dinner: Most people will reach zero BAC within 2 to 3 hours after their last sip.
- Four drinks over a few hours: Expect 5 to 8 hours to fully clear, depending on your size and sex.
- A heavy night out (7 to 9 drinks): You could still have measurable alcohol in your blood 10 to 15 hours later if you’re a man, and potentially well into the next day if you’re a woman.
The common assumption that you’re fine to drive after sleeping it off is often wrong. If you stopped drinking at 2 a.m. after a heavy night, you could still be above the legal limit at 8 a.m. Sleep doesn’t speed up metabolism. Your liver works at the same fixed rate whether you’re awake or asleep.