One standard drink takes roughly one hour to metabolize for the average adult. Your liver processes alcohol at a relatively fixed rate of about 7 grams per hour, and a standard drink in the United States contains about 14 grams of pure alcohol, so the full clearance window is closer to two hours for many people. That “about one drink per hour” figure you’ll see repeated online is a useful shorthand, but the real timeline depends on your sex, body size, and several other factors.
What Counts as One Standard Drink
In the U.S., a standard drink is any beverage containing roughly 14 grams (0.6 fluid ounces) of pure alcohol. That works out to a 12-ounce beer at 5% alcohol, a 5-ounce glass of wine at 12%, or a 1.5-ounce shot of spirits at 40%. These are smaller pours than many people realize. A typical restaurant wine glass holds 8 to 10 ounces, and many craft beers run 7% to 9% alcohol, so a single serving can easily equal 1.5 or even 2 standard drinks.
How Your Body Breaks Down Alcohol
Your liver does the heavy lifting. It uses two enzymes in sequence. The first converts alcohol into a toxic intermediate compound called acetaldehyde, which is a known carcinogen. Fortunately, a second enzyme quickly breaks acetaldehyde down into acetate, a mostly harmless substance your body then converts into water and carbon dioxide for easy elimination.
This process is largely fixed-rate, meaning your liver can only handle so much per hour regardless of how much you’ve had. For a 70-kilogram (154-pound) person, that capacity averages about 7 grams of alcohol per hour, with a total daily capacity somewhere between 170 and 240 grams. You can’t speed it up by willpower, and you can’t outpace it by drinking slowly. Once the enzymes are saturated, any extra alcohol stays circulating in your blood until the liver catches up.
The BAC Timeline
In terms of blood alcohol concentration, most people clear between 0.015 and 0.020 percentage points per hour. Someone who reaches a BAC of 0.08, the legal limit for driving in most U.S. states, would need four to five hours to return to zero. A single standard drink typically raises BAC to somewhere between 0.02 and 0.04 depending on body size and sex, which means a return to 0.00 could take one to three hours.
These numbers assume you stop drinking after that one drink. Each additional drink stacks on top of what your liver hasn’t finished processing yet, extending the total timeline significantly.
Why Women Metabolize Alcohol More Slowly
Sex-based differences in alcohol metabolism are significant. Men have highly active forms of the key alcohol-processing enzyme in both their stomach and liver. The stomach enzyme alone can reduce alcohol absorption by about 30% before it ever reaches the bloodstream.
Women have almost no version of this enzyme in the stomach and a less active form in the liver. The practical result: a woman and a man of the same weight who drink the same amount will typically see the woman reach a higher peak BAC and take longer to clear the alcohol from her system. This isn’t a small difference. It’s one of the main reasons drinking guidelines are lower for women than for men.
Does Eating Before Drinking Help?
Food in the stomach changes the experience of drinking, but its effect on total clearance time is surprisingly small. One well-known study compared drinking on a full stomach versus an empty one and found no significant difference in the total time to reach a zero breath-alcohol reading: about five hours either way. What food does change is the peak. A full stomach can slow absorption, resulting in a lower and more gradual rise in BAC. The overall elimination timeline, though, stays about the same because the liver’s actual processing rate drops slightly when food is present (0.017 per hour versus 0.020 on an empty stomach).
So eating before you drink won’t help you sober up faster, but it can help prevent the sharp spike in intoxication that comes from drinking on an empty stomach.
Caffeine, Cold Showers, and Other Myths
Nothing you can do will make your liver work faster. Coffee is the most commonly believed shortcut, and the research is clear: caffeine does not change your breath or blood alcohol concentration at all. In one study, adding an energy drink to alcohol significantly reduced how drunk people felt, but it did not improve their motor coordination or visual reaction time. Another found no difference in self-estimated BAC between people who drank caffeinated beer and those who drank the regular version.
This is actually the most dangerous aspect of the caffeine-alcohol combination. You feel more alert and less impaired than you actually are, which can lead to riskier decisions, especially around driving. Cold showers and exercise fall into the same category of folk remedies with no measurable effect on alcohol clearance rates. Time is the only thing that works.
Liver Disease and Slower Processing
If you have existing liver damage, your processing time may be longer. Research on patients with cirrhosis found that while the liver’s peak enzyme activity for breaking down alcohol was technically similar to that of healthy subjects, their overall metabolic liver function was only about two-thirds of normal. The structural changes in a cirrhotic liver, including internal blood vessel rerouting and tissue scarring, make the organ less efficient at filtering alcohol even when the enzymes themselves still function. For someone with significant liver disease, that one-hour-per-drink estimate could stretch considerably.
Practical Takeaways for Timing
If you’ve had one standard drink, plan on at least one to two hours before your body fully clears the alcohol. For a more conservative estimate, especially if you’re female, smaller in body size, or haven’t eaten recently, two hours is safer. Here are the key variables that shift the timeline:
- Body size: A larger person has more water volume to dilute the alcohol, resulting in a lower peak BAC and slightly faster clearance.
- Sex: Women absorb more alcohol and process it more slowly due to differences in enzyme activity.
- Liver health: Any existing liver condition can reduce your processing capacity.
- Number of drinks: Each additional drink adds roughly another one to two hours to the total clearance time, since processing is sequential, not parallel.
The fixed-rate nature of alcohol metabolism is the single most important thing to understand. Your liver works at its own pace, and no amount of water, food, coffee, or fresh air will change that pace. The only reliable way to be at zero is to give your body enough time.