Your body processes roughly one standard drink per hour. More precisely, your liver lowers your blood alcohol concentration by about 20 to 23 milligrams per deciliter each hour, which works out to eliminating approximately 14 grams of pure alcohol (one U.S. standard drink) in 60 to 90 minutes. That rate is mostly fixed. Unlike many substances your body handles, alcohol breaks down at a near-constant speed, and there’s no reliable way to accelerate it.
What Counts as One Standard Drink
In the United States, one standard drink contains about 14 grams (0.6 fluid ounces) of pure alcohol. That translates to 12 ounces of regular beer at 5% alcohol, 5 ounces of wine at 12%, or 1.5 ounces of distilled spirits at 40%. A craft IPA at 8% or a generous restaurant pour of wine can easily count as one and a half or two standard drinks, which means your body needs proportionally longer to clear it.
How Your Liver Breaks Down Alcohol
Almost all the alcohol you drink is processed in the liver through a two-step chemical conversion. First, an enzyme transforms ethanol into a toxic byproduct called acetaldehyde, a known carcinogen. Fortunately, a second enzyme quickly converts acetaldehyde into acetate, a much less harmful substance. Acetate then travels to other tissues throughout the body, where it’s broken down into carbon dioxide and water and eliminated.
This two-step process is the bottleneck. Your liver can only run these reactions at a set pace, which is why drinking faster than one drink per hour causes alcohol to accumulate in your bloodstream. No amount of coffee, food, or water speeds up the enzymatic conversion once alcohol is already circulating.
Why Some People Process Alcohol Differently
The one-drink-per-hour rule is an average. Several biological factors shift the actual rate up or down.
Body size and composition: Alcohol distributes through body water. People with more muscle mass and higher body water tend to dilute alcohol more effectively, resulting in a lower blood alcohol concentration from the same amount consumed. Women, on average, absorb more alcohol and take longer to process it than men of comparable weight because of differences in body composition, including a higher proportion of body fat and lower proportion of water.
Genetics: A well-studied genetic variation affects the second enzyme in the breakdown chain. People who carry one copy of this variant retain only 10 to 20% of normal enzyme activity, leading to acetaldehyde concentrations roughly six times higher than normal after drinking. Those with two copies lose more than 96% of the enzyme’s function, with acetaldehyde levels up to 19 times higher. This is the mechanism behind “alcohol flush reaction,” common among people of East Asian descent, where even small amounts of alcohol cause facial flushing, nausea, and rapid heartbeat.
Age: Older adults process alcohol more slowly for several overlapping reasons. Liver enzymes become less efficient over time, circulation slows so less blood passes through the liver each minute, and competing demands from medications and chronic health conditions occupy the same enzymes that would otherwise be breaking down alcohol. The result is that a drink at 70 stays in your system noticeably longer than the same drink at 30.
Chronic heavy drinking: Regular heavy alcohol use activates a backup metabolic pathway that is normally a minor player. This secondary system can ramp up four to tenfold in chronic drinkers, increasing the overall clearance rate. This is one reason heavy drinkers develop metabolic tolerance, appearing less impaired at blood alcohol levels that would significantly affect lighter drinkers. The tradeoff is serious: this same pathway generates harmful byproducts that contribute to liver damage, and it also speeds up the breakdown of many medications, potentially making them less effective.
Rough Timeline for Common Scenarios
Using the average clearance rate of about 20 mg/dL per hour, here’s roughly how long it takes your body to fully eliminate alcohol from your blood after you stop drinking:
- 1 standard drink: about 1 to 1.5 hours
- 2 standard drinks: about 2 to 3 hours
- 4 standard drinks: about 5 to 7 hours
- 6 standard drinks: about 8 to 10 hours
These are estimates for an average-sized person who stopped drinking at the time listed. If you had six drinks over the course of an evening and stopped at midnight, your body likely wouldn’t finish clearing the alcohol until mid-morning. This is why people sometimes blow positive on a breathalyzer the morning after heavy drinking, even though they feel sober.
It’s also worth noting that your body absorbs alcohol much faster than it eliminates it. Absorption can be nearly complete within 30 to 60 minutes on an empty stomach. Because intake speed outpaces processing speed, drinking multiple drinks in a short window causes blood alcohol to spike and then slowly decline over many hours.
How Long Alcohol Shows Up on Tests
Blood alcohol itself clears within hours, following the rates above. But different tests have very different detection windows. A breathalyzer picks up alcohol for roughly 12 to 24 hours after heavy drinking. Urine tests that look for alcohol metabolites (rather than alcohol itself) can detect drinking for up to 48 to 80 hours, depending on the specific test. Hair strand testing has the longest reach, detecting alcohol use patterns over a window of one to six months, though it takes several weeks after drinking for the markers to become detectable in hair.
What Actually Slows or Speeds Elimination
Eating food before or while drinking slows absorption, meaning alcohol enters your bloodstream more gradually and your peak blood alcohol level will be lower. But food doesn’t change how fast your liver eliminates alcohol once it’s in your blood. The distinction matters: eating helps prevent sharp spikes in intoxication, but it doesn’t meaningfully shorten the total time needed to clear alcohol from your system.
Hydration, exercise, cold showers, and coffee have no measurable effect on elimination rate. They may make you feel more alert, but your liver is still working at the same enzymatic pace. The only factor that genuinely increases liver processing speed is chronic heavy drinking, which activates backup pathways at a steep cost to liver health. For the average person, the math is simple: your body clears about one drink per hour, and nothing you do after drinking changes that.