How Long Does Alcohol Stay in Your System?

By Lauren Smith

Last updated: 19 March 2024 & medically reviewed by Dr. Kimberly Langdon

How quickly does alcohol take effect?

Alcohol metabolism begins seconds after you take a drink, as a small amount is absorbed by your tongue and mucosal lining of the mouth and enters your bloodstream.^[1]

After five minutes, alcohol is in your stomach, where about 20% is absorbed and enters your bloodstream. However, enzymes present in the stomachs of some people—alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH)—will break down some alcohol and divert it from entering your bloodstream.

In about 20 minutes, the alcohol will enter the small intestine, where about 80% is absorbed and taken to the bloodstream. Alcohol circulating in the bloodstream and taken to the brain produces the characteristic effects of intoxication. 

You’ll usually feel these within 10 minutes of taking a drink. Alcohol reaches its peak concentration in the blood after around 60 to 90 minutes.^[2]

However, the speed at which alcohol takes effect can vary. One large influence is the presence of food in the stomach. This slows the emptying of the stomach contents into the small intestine, where alcohol is better absorbed. That's why people are advised not to drink on an empty stomach—they'll feel drunker more quickly.^[3]

How long does alcohol stay in your system?

90% of alcohol is metabolized by the liver. The enzyme alcohol dehydrogenase breaks ethanol into acetaldehyde, a toxic chemical that may be the culprit behind some hangover symptoms such as sweating, nausea, and vomiting.^[4] Acetaldehyde is converted into acetate, which is converted into carbon dioxide and water, which are then eliminated from the body through exhaled breath and urine.

The liver can metabolize around 0.015 g of ethanol per 100mL of blood per hour. That’s the equivalent of one standard drink per hour and will reduce your blood alcohol concentration (BAC) by 0.015 per hour.^[2] Any other alcohol accumulates in your bloodstream and tissue until it can be processed by the liver. The presence of this backlog of alcohol will make you feel drunk.

The half-life of alcohol is around four to five hours. That’s the amount of time it takes the body to eliminate half of it. It takes the average person around five half-lives to clear most of the alcohol from their system, or 20 to 25 hours. But your personal metabolism of alcohol could proceed at a much different rate.

Read here to learn how long other substances stay in your system.

What affects how long alcohol stays in your system?

The speed of alcohol metabolism varies widely, depending on the individual and the circumstances. Slower alcohol metabolism means it will stay in your system longer, producing intoxication and leaving traces to be picked up by alcohol testing.

The amount of alcohol you drink and the strength

Your liver can metabolize around 14 grams of alcohol per hour, an amount known as a standard drink. This processing can’t be sped up. If you consume five standard drinks in an hour, the liver will take five hours to clear it.

The type of alcohol doesn’t affect metabolism, but its strength does. For example, liquor contains much more ethanol per ounce than beer, so it takes longer for your liver to metabolize a shot of whiskey than the same volume of beer.

In one hour, your body can metabolize:

• 12 ounces of beer (5% alcohol by volume) or around one can

• 5 ounces of wine (12% alcohol by volume) or around one glass

• 1.5 ounces of liquor (40% alcohol by volume) or around one shot ^[5]

Your stomach enzymes

Some people have enzymes in their stomach that break up alcohol before it reaches their bloodstream to produce the effects of intoxication. These enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), can reduce the absorption of alcohol by 30%.^[6]

Men have a highly active form of ADHs in their stomachs, while women have almost none. This increases the time it takes for women to metabolize alcohol and means they become more intoxicated on smaller quantities of alcohol. People who regularly drink also have less ADH in their stomachs than other people.

Your sex

While women have minimal amounts of ADH in their stomachs, their liver can remove alcohol from the bloodstream more quickly. This is likely because women have higher liver volume per unit of lean body mass.

However, women display higher blood alcohol concentrations (BAC) than men after equivalent amounts of alcohol, even when body weights are the same. This is because women have more body fat and a lower volume of body water compared to men and alcohol is water-soluble. In general, women metabolize alcohol more slowly than men.^[7]

The presence of food

Just 20% of alcohol is absorbed in the stomach, while 80% is absorbed by the small intestine. The presence of food in your stomach will slow this gastric emptying and mean it takes longer for the bulk of the alcohol to reach your small intestine and from there your bloodstream. It will therefore take longer for you to feel the effects of the alcohol and longer for it to be removed from your body.^[8]

Your age

As we age, our body metabolizes alcohol more slowly.

Your drinking history

Heavy drinkers develop a tolerance for alcohol over time: their bodies metabolize and clear it more quickly. However, if you’ve drank heavily long enough to sustain damage to your liver, your alcohol metabolism will slow.

Medication

Some medications can affect the absorption and metabolism of alcohol, generally slowly the clearance. For example, some medications compete with alcohol for breakdown by cytochrome P450 enzymes in the liver, slowing the metabolism of both.^[9]

Genetics

Some people have variants of ADH and ALDH enzymes that act quicker or slower, affecting the rate of alcohol metabolism. Some of these variants have been linked to a higher risk of alcohol addiction. For example, the ADH1B variant of the ADH enzyme significantly slows the clearance of alcohol from the liver and people with it are more likely to become alcohol-dependent.^[10]

Alcohol in drug tests

Alcohol permeates all tissue in the body except bone and fat. It can therefore be detected by drug tests in several ways. However, a direct test for ethanol must be administered within a day of your last drink for alcohol to be detected.

These short detection windows are markedly different from the weeks-long detection windows for drugs that are fat soluble. More advanced tests look for metabolites of alcohol which may linger for several days or even weeks, but these tests are expensive and only done if alcohol use is suspected or for legal purposes.

Alcohol in breath testing

People are most familiar with breath testing for alcohol, as done with the portable breath analyzers used by law enforcement to uncover drunk drivers. Breath analyzers, popularly known as Breathalyzers, from the brand name, detect the small portion of ethanol that is eliminated through your breath. From that figure, your estimated blood alcohol concentration (BAC) can be calculated.^[11]

Breath analyzers can detect alcohol in your breath within 15 minutes of your first drink. They continue to pick up traces of ethanol for as long as there’s alcohol in your system. Because metabolism varies between people, this means breath tests can find alcohol for between 12 and 24 hours.

Alcohol in blood testing

Your blood can be analyzed for ethanol and your blood alcohol concentration (BAC) determined. Typically, ethanol can be detected in your blood for up to 12 hours after your last drink.

However, more advanced blood tests look for phosphatidylethanol (PEth), an abnormal phospholipid formed in the presence of ethanol (EtOH) and a direct biomarker of alcohol consumption. PEth blood testing can uncover prolonged or heavy drinking for up to four weeks.^[12]

Alcohol in urine testing

Just 0.5 to 1.5% of the alcohol consumed exits the body unchanged in the urine.^[13] This ethanol can be found within an hour of your first drink and remains detectable for 10 to 12 hours.^[14]

However, more advanced urine tests have much longer detection windows. These tests look for ethyl glucuronide (EtG), a by-product of ethanol, and glucuronide, a compound produced by the liver to bind to toxins to enable their excretion. 

EtG is formed when someone drinks even the smallest amount of alcohol. Unlike other blood tests, EtG tests can’t determine how much alcohol you’ve consumed. Rather the tests are used to detect any drinking.

But the amount you drink will influence how long EtG can be detected in the urine. After a few drinks, EtG can be founded in the urine for up to 48 hours. With heavier drinking, EtG might be found for three to five days.^[15]

Alcohol in saliva testing

Metabolites of alcohol can be detected in saliva for up to 12 to 24 hours.^[16]

Alcohol in hair follicle testing

Hair testing looks for the presence of ethyl glucuronide (EtG) or fatty acid ethyl esters (FAEEs), two biomarkers of alcohol consumption, only formed when someone has consumed alcohol. Both markers can be absorbed into hair through sweat or diffusion and will contaminate the entire length of the strand. Hair testing is therefore not able to determine exactly when or how much alcohol someone consumed.

But it can prove that someone has consumed alcohol at some point within the detection window. This detection window is lengthy: up to three to six months.^[17]

How can you sober up quickly?

If you’re looking to sober up in order to drive or are angling to pass an alcohol test. you might hope you can remove alcohol from your body more quickly. Urban legends suggest drinking coffee, getting fresh air, taking a cold shower, and exercising can speed up the removal of alcohol from your body. 

However, while these tactics might make you more awake and alert, they won’t reduce your blood alcohol concentration or speed up the elimination of alcohol.^[18]

90% of alcohol is metabolized by your liver. The liver can only clear 0.015g of ethanol per 100mL of blood per hour. It will therefore lower your BAC by 0.015 per hour. Medications and liver damage can reduce the speed of metabolism but nothing can speed it up.

The remaining 10% of the ethanol you consume is excreted through urine, sweat, and breath. You may be able to drink a lot of water to encourage urination and clear alcohol a little more quickly from your urine. However, diluted samples won’t be accepted for testing, earning you an automatic fail.

In short, you can’t expedite your body’s removal of alcohol. You therefore shouldn’t drink if you intend to drive and shouldn’t consume alcohol if you’ll be subjected to testing.

When can you be asked to take an alcohol drug test?

There are several situations in which you might be asked to take a test to detect alcohol consumption or level of intoxication.

You’re suspected of drunk driving

You may be pulled over by law enforcement if your driving suggests you’re impaired, stopped at a sobriety checkpoint, or approached following a road traffic accident. Law enforcement will perform a field sobriety test and/or ask you to blow into a portable breathalyzer. 

If you’re found to be over the legal limit, you’ll usually be taken to a police station where you’ll be required to submit to more precise testing, usually an evidential breath testing device or a blood test. Laws vary by state, but if you refuse to comply with testing, you’ll face penalties.^[19]

If you’re unconscious following a road traffic accident, police can order a blood test to look for evidence of intoxication without a warrant, the Supreme Court recently affirmed.^[20]

By your employer

Depending on state law, companies have the right to test employees for alcohol and drug use. Sometimes this testing is part of the hiring process. It may also be done following a workplace accident or injury. 

The government legally requires that companies in some industries such as transportation and aviation drug and alcohol test employees in certain roles.^[21] 

As alcohol consumption is legal and 55% of adults have had an alcoholic beverage in the previous month, employers usually aren’t interested in whether you’ve ever had alcohol.^[22] Rather, they want to know if you’re drunk on the job. 

You’re part of a treatment program

Some rehab programs test participants to see if they’re truthful about abstinence and to give them a sense of accountability.

You’re part of an investigation

Whether you were drunk or had any alcohol during a certain period may be important to a criminal or civil case, whether you’re a defendant or witness.

As part of family court proceedings

For example, alcohol tests may be requested or ordered by the court as part of a child custody dispute, but usually only if there is credible evidence that the parent has abused alcohol in the past.^[23]

You’re in the hospital

If you arrive at the hospital unconscious, confused, or showing other signs of intoxication, doctors may order a breath or blood test to determine how to best care for you.

You're applying for life insurance

As part of the underwriting process for life insurance, you must disclose details about your health, including your drinking habits. The insurer may ask you to corroborate your claims with an alcohol test.

You’re being considered for a liver transplant 

Drinking alcohol can often disqualify you from a liver transplant.

Getting treatment for alcohol use disorder

If you’re trying to sober up before driving or work or an alcohol test, it’s an indication that you’ve lost control of your drinking—a key symptom of alcohol use disorder.

Alcohol use disorder is treatable. While you alone must decide to recover, you don’t have to walk the path to sobriety alone. Help is available, in the form of therapy, medication, and mutual aid meetings. Treatment may include medical detox, an inpatient stay in a rehab facility, and ongoing appointments to monitor your progress.