How Long Does Alcohol Stay in Your System?

The lifespan of alcohol in the body is relatively short, although it could be longer due to a number of reasons. Drinking large quantities of alcohol is a primary protagonist. Sometimes, alcohol will leave the system with accompanying unpleasant symptoms. This usually occurs when you are addicted to or have abused alcohol.

Binge drinking is harmful to the body. This is because ingesting more alcohol than the body can process will cause what is left in the queue (to be metabolised) to take up residence in the blood and tissue. This will more than likely lead to brain and tissue damage if it continues to happen.

Alcohol is processed differently in every person due to biological differences such as age, gender, weight, genetics, body composition and medical condition. In each individual, the length of time it takes for alcohol to leave the body will primarily depend on the amount consumed, since the body digests the substance in a fairly straightforward manner.

With that said, there are a number of general guidelines that can be applied to an average person to ascertain when alcohol will leave the system. The substance is transported out of the body mainly through the liver. When it finally leaves the body, traces of alcohol may linger in certain areas, including the blood, urine, hair and breath.

Coupled with the amount you consume, the speed at which your body digests and processes alcohol will factor in the duration of its presence in your system.

If you are worried that your system is not filtering out alcohol as it should – or if you have abused alcohol and are concerned about the difficult phase of withdrawal – we can help. With professional assistance, you can get to the root of your alcohol problems and rid the toxic remnants of the substance out of your system, safely.

How the body processes alcohol

Alcohol goes through your metabolism faster than food and other drugs. It is a depressant that needs little digestion, or none. Your level of alcohol intake and the rate at which your body metabolises the substance will come together to determine how fast – or slow – it will leave your system.

When ingested, alcohol goes straight to the stomach (where metabolism begins) where it

encounters small blood vessels that ferry nutrients and water throughout the body. These blood vessels transport about 20% of the alcohol into the bloodstream, while the remaining 80% goes to the small intestine, where it meets a larger concentration of small blood vessels that also go around the body.

This means that alcohol reaches organs in the body at a fast rate. Once alcohol has found its way into the bloodstream, it speedily travels through the entire body. This is when intoxication and other effects of alcohol begin to occur.

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In cases where alcoholic content does not go through metabolism in the stomach and small intestine, it is eliminated from the body through your urine, saliva, or sweat.

The liver is responsible for the majority of the alcohol metabolism process. This is because most of the alcohol that is absorbed by blood vessels eventually ends up in the liver. The liver is one of the biggest victims of alcohol abuse, because of its prominent involvement in alcohol processing.

Also, liver failure will lead to a slowed metabolic process, which will cause alcohol to remain in the body and cause further damage. If you have a weak liver, it is advisable to stay off alcohol.

The rate at which your liver processes alcohol will not be influenced by the amount you consume. Your liver will metabolise approximately one unit of alcohol per hour. If you consume more than this, your blood and tissue will take up the rest of the alcohol units yet to be metabolised and serve as their reservoir.

Alcohol metabolism

Your liver houses the main enzymes involved in alcohol metabolism. They are commonly called hepatic enzymes because of their presence and activity in the liver. They are cytochrome P-450 2E1 and alcohol dehydrogenase.

Alcohol dehydrogenase (ADH) is an enzyme that is also found in the stomach. This enzyme will completely metabolise the alcohol consumed in the stomach if your consumption is light.

ADH breaks down alcohol into acetaldehyde, which is further converted to a substance that can be easily absorbed and evaporated by your body, called acetate. The acetate is produced through an extension enzyme called acetaldehyde dehydrogenase.

The activity of both enzymes (acetaldehyde dehydrogenase and alcohol dehydrogenase) will result in changes in a coenzyme called nicotinamide adenine dinucleotide (NAD), which is responsible for energy production. This will lead to a halt in glucose conversion until alcohol is processed.

Cytochrome P-450 also acts in a similar manner to ADH, but will be more concentrated in your liver if you abuse alcohol regularly and are a chronic drinker. More of this enzyme in your liver will result in the release of a number of radicals that may cause inflammation and damage other organs.

Though a depressant, Ethanol (alcohol) is also a nutrient in its biological form. It has a high calorie value – about 7 kcal per gram. However, unlike fats and carbohydrates which can be stored and used when needed, ethanol remains in body liquids (including the blood and tissue) until it is eliminated.

When alcohol is present in the system, it is preferentially metabolised over other elements. This means that alcohol-based calories are processed by the body at the expense of other fat and carbohydrate-derived calories.

How long does alcohol stay in your system?

Normally, it will take your body roughly one hour to process a single unit of alcohol. This means if you consume 30 units, alcohol will be present in your body for a whopping 30 hours.

How much alcohol is one unit?

A unit is equivalent to 8g or 10ml of pure alcohol. You can identify alcohol levels as follows:

  • Each 175ml standard glass of average-strength wine (12%) contains 2.1 units of alcohol, with 3 units contained in a large glass (250ml)
  • A single pint of low-strength lager, cider or beer (3.6%) contains 2 units
  • One pint of higher-strength lager, cider or beer (5.2%) contains 3 units
  • One measure of spirits (25ml) contains 1 unit

Matching the measures

From the measures above, here is the duration of alcohol presence in your body for drinks consumed:

  • A large glass of wine will take three hours to leave your system
  • If you consume half a bottle of wine, your body will require 4.5 hours to get rid of the alcohol
  • One bottle of wine requires nine hours for the alcohol to leave your system
  • A single pint of low-strength beer will take two hours to be expelled from your body
  • One higher-strength pint of beer will be in your system for three hours
  • It will take your system one hour to rid itself of a single 25ml vodka measure and 20 hours for a 500ml bottle

Despite alcohol being metabolised by your body, traces of the substance may linger in bodily fluids such as your blood, sweat, saliva and urine, as well as other body parts like your hair and breath. Alcohol can be detected by testing for the substance in any of these areas.

Alcohol levels in the blood

Alcohol leaves the blood relatively faster than it does from hair follicles, sweat and urine. The timeframe for alcohol elimination will depend on the amount of alcohol consumed, the rate at which the body processes the substance and a host of other factors.

However, an indicator that helps determine the level of alcohol in the blood at any given moment is the blood alcohol concentration (BAC). Generally, alcohol leaves the blood at 0.015 BAC per hour. For example, a person with a BAC level of 0.08 will have alcohol present in their blood for 5.5 hours.

Blood tests may be carried out to determine if a person is driving illegally or is under the influence. These could also be carried out during a routine blood check-up when enrolling in a detox programme. These tests basically look for your BAC level.

In the UK, the legal driving limit in England, Wales and Northern Ireland is 80mg per 100ml of blood (0.08 BAC) and in Scotland, it is 50mg per 100ml of blood (0.05 BAC).

What is blood alcohol concentration?

Blood Alcohol Concentration (abbreviated as BAC and also known as blood alcohol content, blood alcohol level and blood ethanol concentration) is a standard metric used to determine alcohol presence in the blood. Essentially, it measures the alcohol percentage in the blood. For example, if your BAC level is at 0.1, this would mean that your blood is 0.1% alcohol (in the US).

Each country employs different units for measuring BAC. In the UK, it is measured in milligrams of alcohol per millilitre of blood. For example, a BAC of 0.05 amounts to 50mg of alcohol per 100ml of blood.

BAC is commonly used for medical and legal purposes. If you have consumed alcohol, there is a limit that indicates you’re not legally qualified to get behind the wheel of a car. In a medical setting, a certain level of BAC would indicate that you have abused the substance. It is also used in diagnosing alcohol dependence and other health issues caused by excessive alcohol consumption.

Alcohol levels in urine

Alcohol is present in urine for a longer period than the blood. Testing urine is regarded as one of the most effective means of detecting alcohol usage. The test used for detecting alcohol through urine is known as an Ethyl Glucuronide (EtG) test. This can detect the presence of alcohol in urine up to 96 hours after of your last drink.

Ethyl Glucuronide is a direct metabolite in alcohol, meaning that even after it has been eliminated from your blood, traces can still be found in urine. An ETG test can signal that you’ve been consuming alcohol within the previous 96 hours. Even when you have been drinking moderately, a urine test for alcohol can come back positive after three to four days.

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Alcohol levels in breath

Alcohol can also be detected via the breath, as long as it is present in the body. The presence of alcohol in your breath will rely on how much you have consumed and other biological factors. At the normal rate of alcohol elimination (which is 1 unit per hour), traces of alcohol would have disappeared in accordance to the amount you have consumed.

For instance, should you consume one large glass of wine, it will ideally take your body three hours to expel any alcohol it has absorbed. This means that during those three hours, your breath may smell of alcohol. Even if it is faint or you try to fool the olfactory senses of those around you, there is a breath-based test that can detect the presence of alcohol in your body, via your breath. The test is conducted with breath alcohol testing devices, commonly known as breathalysers.

What is a breath alcohol test?

A breath alcohol test takes the measurement of your BAC, which determines how much of the substance is in your system. Your blood alcohol level is analysed by measuring the amount of alcohol you exhale.

You can conduct this test by yourself, using a simple hand-held breath-testing device. You can get an accurate estimate of your BAC if the device has been properly configured and the manufacturer’s directions are followed correctly, when carrying out the test. Different types of breath testing devices are available and you can acquire devices for home use, or professional variations, used mostly by law enforcement agents and medical personnel.

There are electronic devices that show a digital figure of your estimated blood alcohol level in a display window, after you’ve blown air into the mouthpiece. The manual variants come in the form of glass tubes (some with balloons) that contain colour-changing crystals that identify the presence of alcohol in your breath. Electronic breath analysers are more expensive than manual breath testing machines.

The breathalyser will come in handy if you’re unsure about the level of alcohol in your system, especially when you want to drive.

When to take the breath alcohol test

Wait for 15 minutes after your last drink before taking the breath alcohol test. This will ensure the results are not falsified by alcohol residue in your mouth from a drink you recently consumed.

Ensure that you’ve not used a mouthwash or mouth-spray, as they could contain alcohol that would skew test results. Also, refrain from smoking and do not blow smoke into the device.

Please follow the manufacturer’s instructions properly and conduct at least two tests, 15 minutes apart.

Alcohol levels in hair

Alcohol can be detected in the hair for a longer amount of time than other parts of the body. Hair alcohol tests can detect traces of the substance in follicles as long as three months after your last alcohol consumption.

The test is considered as one of the most established and accurate methods for flagging alcohol consumption. The test is conducted by seeking out Fatty Acid Ethyl Esters (FAEE) and EtG markers in the hair. These markers of alcohol consumption are absorbed into the hair from sweat and diffusion. They go on to contaminate the hair’s entire length.

Peak levels and half-life of alcohol

A single serving of alcohol takes anywhere between 30 minutes and two hours to be fully absorbed into your bloodstream after intake. This is because the liver breaks down alcohol at one unit per hour. However, alcohol affects each person differently, depending on certain factors and the quantity of drinks you may have consumed at any given time. Some variants that may factor in the peak levels of alcohol and effects include:

  • Your metabolism rate
  • Related food intake
  • Your weight and size
  • The amount of alcohol consumed

Overall, alcohol is metabolised at a slower rate than it’s absorbed into the mainstream. This means your body stores alcohol faster than it can get rid of it. For example, if you weigh 68kg, each low-strength pint you consume adds two units of alcohol to your system, but your body will dispense only one unit in an hour. This is why your BAC builds steadily throughout a drinking session.

Amount of alcohol consumed: This is the primary factor that generally affects the rate of metabolism in every individual. The more you consume, the more alcohol still to be metabolised piles up in your bloodstream. The alcohol which has not been metabolised is responsible for causing intoxication (because it travels to the brain through the bloodstream) and interactions with other body systems.

Size and weight: People of a smaller size and body weight break down alcohol faster than those of a relatively larger size and body weight.

Race: A number of studies (though not all) suggest that there is a higher rate of alcohol elimination in native Americans, Asians and Inuits than Caucasians. The Chinese metabolise alcohol slower than Caucasians.

It’s also been reported that the mass of liver may explain ethnic variations in alcohol metabolism rates.

Gender: When alcohol elimination rates are adjusted for lean body mass, women tend to process and break down alcohol faster than men. This is because women normally have a leaner body mass than men.

Generally speaking however, men and women metabolise alcohol through the liver at the same rate when figures are calculated based on unit per hour measurements.

However, there is a larger stomach content of alcohol dehydrogenase (ADH) in men than women. ADH presence in the stomach results in a lower percentage of alcohol travelling to the small intestine. This happens because more alcohol has been metabolised in the stomach.

Women have lower levels of ADH in their stomach, regardless of race, leaving the liver with more alcohol molecules to break down. This explains why women become tipsy faster than men.

Age: Alcohol leaves the body faster in matured adults. This is because younger people have low alcohol metabolism capacities, as enzymes in their liver are not fully expressed. The livers of unborn babies break down alcohol poorly, which may lead to foetal alcohol syndrome if alcohol is consumed by the mother during pregnancy.

In elderly individuals, alcohol metabolism may be slower, due to reduced body water content or liver mass.

Food: The amount of food present in your stomach can affect how fast alcohol is absorbed and broken down by your body. A full stomach halts the movement of alcohol into the intestine. This is because the stomach is closed in order for food breakdown to take place. This reduces the rate of intoxication, as the majority of alcohol needs to travel to the small intestine to be absorbed.

Liver blood flow may also be increased by food. Alcohol metabolism is enhanced by the presence of fructose, which provides substances that boost the activity of NAD. The rate of alcohol elimination is increased by different kinds of food, regardless of composition. Studies show there is no difference between fat, protein and carbohydrates in terms of alcohol metabolism.

Drugs: Some pharmaceuticals can slow down the speed of alcohol metabolism by reacting with and inhibiting certain enzymes. H2 receptor antagonists – such as cimetidine (Tagamet) and aspirin – may reduce the activity of ADH enzymes found in the stomach. This will lead to increased levels of alcohol in your bloodstream.

Acetaldehyde (a major component of metabolism) can also be inhibited by disulfiram (Antabuse), which results in decreased alcohol elimination rate.

Alcoholism: If you consume alcohol chronically and are an abusive drinker, your body will metabolise alcohol faster than light to moderate drinkers. Continuous heavy drinking is also bad for the liver. It will lead to slowed metabolism of alcohol (as well as general metabolism) in the long run, as a result of liver damage caused by continuous presence of excessive alcohol.

Health: Your general health – especially liver health – will greatly influence the rate at which your body eliminates alcohol. If your alcoholism results in liver damage, or if your liver is damaged for other reasons, your body will struggle to break down the substance in normal time.

What the alcohol was mixed with: Certain agents mixed with (or consumed alongside) alcohol will alter the timeframe for metabolism. If you mix alcohol with caffeinated beverages or sports drinks, your body will absorb the substance rapidly. However, other liquids such as juice or water may cause absorption to occur slowly.

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Detection timetable depends on many variables

Figuring out how long alcohol will be detected in the system relies on a number of variables. A prominent variable is the kind of test used in detecting alcohol, which will completely disappear from some body parts in a short period of time, making it undetectable to some tests. However, in select areas, alcohol traces (especially metabolites of the substance) can be detected for a relatively long time.

The alcohol detection timetable can also be altered by other variables related to your particular rate of metabolism, including ethnicity, liver health, age, weight, size, gender, rate of alcohol intake and drugs.

Below is a general timetable for detecting alcohol via various tests:

  • Breath tests – Alcohol can be detected in the breath from 12-24 hours after intake by a breathalyser
  • Blood tests – Alcohol may remain in the blood for 12 hours and can be detected by a blood test during this timeframe
  • Urine tests – Urine tests look for Ethyl Glucuronide (EtG), which can linger for three to five days
  • Hair follicle – Alcohol can be detected in your hair follicle three months after your last consumption, as with other drugs

Getting sober: Expunging alcohol from your body

The only ingredient for sobering up and lowering your BAC to zero is time. Once the alcohol has been consumed, your only option is to wait. The body will not accelerate its metabolic pace, no matter what.

If you have a bad liver, your alcohol metabolism will be slower and take a long time to complete. Try to cut back on your drinking if you are suffering from liver disease. If you’ve consumed lots of alcohol in this state, please contact your doctor.

Remember to wait until you’re completely free of alcohol before driving. Consuming lots of coffee, food, or water will not speed things up. After a night out involving heavy drinking, you may have to wait a full day or more to sober up.

If you’ve been abusing alcohol for a long time and are addicted to the substance, there’s a good chance you’ll experience withdrawal symptoms if you attempt to quit drinking for good. These symptoms can be very unpleasant and uncomfortable – and, in extreme cases, might present life-threatening complications. Please consult a doctor for help if you fall into this category.

Help is available if you are struggling with your alcohol addiction. Addiction is difficult to fight, but you can win the battle with proper help and prevent future complications of alcoholism.

Myths about alcohol in your system and detection

It’s often misconceived that gulping down certain fluids or undertaking physical activities will speed up alcohol metabolism. Some companies also market products that claim to help eliminate alcohol from your system and sober you up in no time. These claims and activities are myths and will have no effect on your body’s alcohol elimination process.

The following activities will not accelerate sobriety, eliminate alcohol from your body, or cause your liver to metabolise alcohol more quickly:

  • Eating after consuming alcohol
  • Consuming liquids such as black coffee, sports drinks and similar beverages
  • Taking a cold shower
  • Exercising

While some fructose in food can help boost liver blood flow, the significance in metabolism is not substantial. Since the amount of enzymes in your body are unlikely to increase via food intake, alcohol will be broken down at the normal rate.

Facts about alcohol in your system

Here are some quick facts on how alcohol passes through your system:

  • About 20% of alcohol is absorbed in your stomach and the rest in the small intestine
  • 90% of the alcohol you consume is broken down by the liver
  • Alcohol begins to affect you when it travels to the bloodstream and body tissue
  • The liver metabolises one ounce of alcohol per hour
  • Alcohol can be detected after intake in the urine, blood, saliva, breath, sweat and hair
  • Consuming food, coffee and energy drinks, exercising and engaging in physical activities and taking pharmaceuticals cannot speed up how your body eliminates alcohol

FAQs

How is alcohol metabolised?

Alcohol is broken down mainly in the liver. The metabolism process involves alcohol dehydrogenase (ADH) breaking down alcohol molecules into acetalhyde, which is further broken down into harmless acetic acid that is evaporated from your system. Another enzyme – Cytocrome P450 2E1 (CP2E1) – is also actively involved in metabolism, but more so in chronic alcoholics.

How is alcohol digested?

Alcohol requires relatively little digestion. Sometimes, it isn’t digested at all. When consumed, it goes directly to the stomach from the oesophagus. From there, it gets absorbed into the bloodstream.

About 20% of what is consumed encounters blood vessels in the stomach and travels through the bloodstream. The rest enters the blood when it gets to the small intestine.

Does drinking coffee help you process alcohol and sober up faster?

No. Drinking coffee will not sober you up any faster than your liver will. If you have consumed alcohol, you will have to wait for your liver to do its job and rid the alcohol from your system.

Can an EtG test detect alcohol long after it’s gone?

Yes. EtG tests detect the presence of Ethyl Glucuronide, an alcohol metabolite in urine. EtG can linger in the body for up to 96 hours after your last alcohol intake. Thus, alcohol can be detected during this window.

For how long do breathalysers detect alcohol?

Breathalysers will detect alcohol in your breath up to 24 hours after consumption, depending on the amount of alcohol consumed.

What tests check for blood alcohol concentration (BAC)?

Your BAC can be estimated by a variety of different tests. These include urine, saliva, blood, hair and breath tests.

Urine tests may not be reliable in determining your BAC level, as various studies have suggested. This is because urine samples can be affected as time goes by, and might only detect evidence of alcohol use long after it has left the system – and may be EtG-based.

More accurate estimations of BAC levels can be carried out by blood tests and breath tests.

How can I avoid detection during tests?

The best way to pass any alcohol test is to wait until your liver processes the alcohol in your system. Although there are ‘detox drinks’ being marketed for flushing capabilities, these products aren’t reliable.

It is not advisable to attempt to ‘beat’ an alcohol test if you’re involved in a dangerous job where safety at work is paramount. This is because you could be putting yourself – as well as others – at risk, working under the influence.

Can I drive the morning after drinking alcohol?

This will also depend on the amount of alcohol you consumed the night before. If you consume just one pint of high-strength lager, you may be legally able to drive the next day. If your BAC is beyond 0.08 in the morning however, it will be deemed illegal for you to drive if you’re in England, Wales or Northern Ireland. In Scotland, however, a BAC reading of 0.05 legally precludes you from driving.

How long does alcohol stay in your system?

Alcohol will remain in your system depending on the number of units you consume. One unit of alcohol leaves your body every hour.

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