How Long Does Alcohol Stay in Your System? Factors of Alcohol Metabolism Rate

On average, the body can metabolize 14 grams of alcohol per hour, the amount found in one U.S. standard-sized drink, but how long alcohol impairs your body’s functioning (e.g., how long alcohol affects your driving), and how long it is detectable, varies greatly. While normal body function may largely return once alcohol is metabolized (e.g., 1 hour on average for a standard drink), it remains detectable for up to a few weeks.

How long alcohol stays in your body depends on a variety of factors, including your age, weight, sex, and overall health. Similarly, how long alcohol is detectable in the body via a test depends on the type of test used.

Before going into further details of how long alcohol stays in your system, and for how long it can be detected , it’s first worth recalling just what happens inside your body when you drink.

How Is Alcohol Metabolized?

Once consumed, alcohol is quickly absorbed into the bloodstream, which does the job of transporting it throughout the body. While the stomach breaks down some of the alcohol, the bulk of metabolism or processing alcohol occurs in the liver, which produces enzymes that break up the alcohol molecules.

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What Is Blood Alcohol Concentration (BAC)?

Blood alcohol concentration (or blood alcohol content) is a measure of the amount of alcohol in your bloodstream. BAC is determined by a blood alcohol test that measures the number of grams of alcohol within 100 ml of blood. The result is given as a percentage.

If your BAC is 0.01%, it means the test found 0.01 grams of alcohol in 100 ml of your blood. The higher your BAC, the more impaired you are. In every U.S. state, it is illegal for anyone over age 21 to drive with a BAC higher than 0.08%.

What Is a Standard Drink?

In the U.S., a standard drink is a single drink that contains .6 fluid ounces, or 14 grams, of alcohol. This equates to:

- 12 ounces of beer containing about 5% alcohol

- 5 ounces of wine containing about 12% alcohol

- 1.5 ounces of a distilled spirit containing about 40% alcohol

While the exact amount of alcohol in beer, wine, and spirits varies, the standard drink is a useful measure to keep track of how much alcohol you consume.

How Long Is Alcohol Detectable in Your Body?

If you’ve been drinking, you may be wondering for how long alcohol can be detected in your system. While the widely known breathalyzer test is one common way to tell, there are several methods of testing for alcohol in the body.

What all the tests have in common is that they search for the presence of alcohol metabolites, which are byproducts of the process of alcohol metabolism.

The tests below are the most commonly used methods of testing for alcohol consumption. The timeframes listed are the general maximum amount of time after drinking that the test can detect alcohol metabolites in your system.

- Blood—12 hours

- Breath—24 hours

- Saliva—48 hours

- Urine—5 days

- Hair—90 days

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Factors That Affect How Your Body Absorbs and Metabolizes Alcohol

While the body follows a standard process for absorbing and metabolizing alcohol, how fast it does this is different for everyone. And over time, your body and even parts of your body adjust, for instance, alcohol's affect on the brain can be relatively short or life-long. Along with the obvious factor of how much alcohol you consume within a given timeframe, the elements below help explain why alcohol is absorbed faster or slower, and stays in the body longer, of some people compared to others.

Age

As we get older, our bodies generally become less efficient at metabolizing alcohol. Research has found this is due to reduced overall circulation, a decrease in the body’s total water content, and decreases in lean muscle mass, all of which are normal occurrences as we age.

Sex

Research has found that women have less of the enzyme alcohol dehydrogenase (ADH) in their stomachs compared with men. ADH, which is also in the liver, is one of the key players responsible for breaking down alcohol. With less ADH in their bodies, women tend to metabolize alcohol slower than males.

Height & Weight

Because larger people have comparatively more blood and water in their bodies than smaller people, a larger person absorbs alcohol more slowly — and thus has a lower blood alcohol concentration — than a smaller person, even if they drink the same amount.

However, the higher percentage of body fat a person has the higher his or her blood alcohol concentration will be. This is because fat tissue contains less water than lean tissue, leading to less total body water and thus more alcohol in the blood.

Genetics

Research has found different genetic variations of the enzymes that break down alcohol. Because some versions of these genes are better than others at metabolizing alcohol, your genetic makeup helps determine how quickly your body breaks down alcohol and also how alcohol affects you.

These genetic variations help to explain why people of certain ethnic groups tend to have similar responses to alcohol. For example, a genetic variant more common in people of East Asian descent can cause a facial flushing reaction from drinking alcohol.

Medications

Both over-the-counter and prescription drugs may alter the effects of alcohol on your body. In turn, alcohol may interfere with the intended effects of medications.

If you’re taking a prescription medication, ask your doctor or pharmacist about possible interactions with alcohol.

Antihistamines and pain relievers such as acetaminophen and ibuprofen are two examples of common over-the-counter medicines that can have problematic interactions with alcohol.

Many antihistamines make people drowsy — an effect enhanced by the sedative effects of alcohol. Combining acetaminophen with alcohol can have negative effects on the liver, and ibuprofen in combination with alcohol may cause damage to the lining of the stomach.

Food Consumption

Eating food while drinking or drinking after a meal, versus on an empty stomach, can change how quickly alcohol is absorbed into your bloodstream. The presence of food in the stomach slows the absorption of alcohol into your system and delays the raising of your blood alcohol concentration. The slower absorption of alcohol gives the stomach and the liver more time to break down the alcohol you drink.

How Long Does It Take for Alcohol to Leave Your Body?

While alcohol half-life is fairly short, the body's method of processing alcohol means it can metabolize one standard drink per hour (some people will metabolize this amount quicker and some slower).

How much your blood alcohol concentration (BAC) rises from one drink, and thus how quickly you'll feel buzzed and drunk, will depend on all of the factors outlined above (i.e., weight, sex, age, genetics, food consumption).

Thus, to get to a BAC of 0.08, you and your drinking partners may require different amounts of alcohol. Getting your BAC back down to zero after drinking, however, is dependent on only one thing: time. A person's BAC goes down by 0.015% per hour once they’ve stopped drinking and start sobering up. ¹

If your BAC reaches 0.08, it will be back to zero in about five to six hours as you're sobering up. But remember, alcohol can have surprising effects on your body —alcohol can even affect your appearance — and even after your body has metabolized all of the alcohol you’ve consumed, some of the tests noted above can still detect that you’ve been drinking for a long time afterwards.

FAQ: How Long Does Alcohol Stay in Your System?

How much does your BAC drop per hour?

Your blood alcohol concentration (BAC) drops by 0.015% per hour.

How much alcohol is metabolized per hour?

On average, the body can metabolize 14 grams of alcohol per hour, the amount found in one U.S. standard-sized drink.

Does drinking water or coffee help alcohol leave your system?

No. Drinking water or coffee cannot “flush out” or dilute alcohol in your body. Water can help counter the dehydrating effects of alcohol, and coffee may help you feel more alert, but neither has any effect on the amount of alcohol in your system.

Can I pass an alcohol test in 24 hours?

It depends on the type of test administered. A blood test can typically detect alcohol consumption for up to 12 hours after drinking and breath tests may detect alcohol for up to 24 hours. Saliva, urine, and hair follicle tests can detect alcohol well past 24 hours.