How Long Does Alcohol Stay In Your Blood

How Long Does Alcohol Stay In Your Blood, How The Body Processes Alcohol, Blood Alcohol Concentration, Tips on How to Keep a Low Alcohol Blood Concentration

How Long Does Alcohol Stay In Your System?

You may have asked the question: how long does alcohol stay in your blood? Or probably you are wondering why do you need to bother? Knowing how long alcohol remains in your system is important for avoiding dangerous interactions with medicines as well as impairments in your mental and physical performance. 

While alcohol is not considered a controlled substance under the Controlled Substances Act (CSA) [1], it is illegal to sell or serve anyone under the age of 21 in the United States. The metabolism of alcoholic substances has been studied in detail. However, there are many unique factors that determine how long it can be detected in your system and how long it will take to be expelled.

Depending on the type of test used as well as your body mass, age, genetics, sex, and overall health, alcohol can remain detectable in your system from ten hours to ninety days. When abused, alcohol can do as much harm as many illegal drugs. Individuals who abuse alcohol also risk developing psychological and physical dependence and alcohol use disorder or alcoholism.

How Long Does Alcohol Stay In Your Blood
Remember—alcohol is alcohol. A breathalyzer doesn’t distinguish between a shot or “just a beer.” It affects your blood alcohol concentration (BAC) the same way
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How Long Does Alcohol Stay In Your Blood?

How long alcohol can be identified in the blood depends on a variety of factors, including what kind of alcohol is consumed, the test used, and many more. People with healthy livers can normally break down or metabolize one unit of alcohol in the span of an hour. The most reliable way of determining blood alcohol levels is a blood alcohol test. These types of tests are only accurate within six to twelve hours after your last drink.

One alcoholic unit is set as 10ml or 8g of pure alcohol, which is roughly equivalent to:

  • a large glass (250 ml) of wine (12 percent alcohol) = 3 units
  • a standard glass (175 ml) of wine (12 percent alcohol) = 2.1 units
  • one pint of low-strength lager, beer, or cider (3.6 percent alcohol) = 2 units
  • one pint of strong lager, beer, or cider (5.2 percent alcohol) = 3 units

How The Body Processes Alcohol

The amount of alcohol you consume and the speed at which your body processes alcohol determine how long alcohol is in your system. Alcohol is metabolized, or processed, in the body more quickly than most substances, and a very high percentage of the amount of alcohol you consumed is actually metabolized. Alcohol normally enters the body through the mouth. It then goes down the esophagus and into the stomach. The metabolism of alcohol starts in the stomach. Small blood vessels encounter alcohol there and start to carry it throughout the bloodstream. 

About 20% of the alcohol that enters the bloodstream does so in the stomach. The remaining alcohol travels through the small intestine, where it finds higher concentrations of blood vessels. The 80% of alcohol that doesn’t enter the bloodstream through the stomach does so through the small intestine.

Once in the blood, alcohol is rapidly carried throughout the whole body, which is why alcohol impacts so many different body organs. Most alcohol that enters the body eventually ends up in the liver, where the huge majority of alcohol metabolism takes place. Because the liver does most of the heavy work in alcohol processing, it is generally the part of the body that is most affected and harmed by long-term alcohol abuse.

The two enzymes that are essentially responsible for alcohol processing are found in the liver, both of which break down ethyl alcohol (drinking alcohol) into Acetaldehyde, which is then further broken down into substances the body can absorb. Alcohol dehydrogenase (also found in the stomach) breaks down almost all of the alcohol taken by light, social drinkers. Alcohol dehydrogenase transforms alcohol into energy. Cytochrome P450 2E1 is very active in the livers of heavy, chronic drinkers. This enzyme actually depletes the body of energy in order to break down alcohol [2].

A third enzyme called catalase, which is present in cells throughout the body, also processes a small amount of alcohol. Acetaldehyde released into the brain via catalase metabolism can link with neurotransmitters to form tetrahydroisoquinolines, which some experts believe are the cause of alcoholism (though this is controversial). These experts believe that the appearance of tetrahydroisoquinolines can be used to determine whether a person is a social drinker or an addicted drinker.

Many factors affect alcohol processing speed, including body weight, medications or recreational drugs, biological gender, food intake, medical health issues, and drinking pace. This suggests that no two people metabolize alcohol at the exact same rate. However, alcohol processing is exceptionally consistent for most people. As a general rule, most people process one standard drink (one glass of wine, one beer, or one-shot) per hour.

Your body is very effective at processing alcohol, provided that the alcohol is not drunk so quickly that alcohol poisoning happens. Between 90% and 98% of all alcohol that enters the body is processed and absorbed. The remaining alcohol is excreted through urine, sweat, vomit, and feces.

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Blood Alcohol Concentration (BAC)

The percentage of alcohol in someone’s bloodstream is known as the Blood Alcohol Concentration (BAC). BAC is usually expressed as a percentage of ethanol present in the blood in units of mass of alcohol per volume. For most individuals, one ounce of alcohol will produce a .015% blood-alcohol concentration. This suggests someone with a .015% blood-alcohol level will have little to no alcohol in their bloodstream after 10 hours have passed. It’s important to note that the more someone drinks, the longer alcohol stays in the system.

How Long Does Alcohol Stay In Your Blood
“How long does alcohol stay in your system?” and “How long does alcohol stay in your blood?” are two commonly asked questions regarding alcohol in the body, and they’re asked for several reasons. Perhaps you’re getting alcohol testing for a job or you’ll be enrolling in a detox program.

According to the National Center for Biotechnology Information (NCBI) [3], alcohol produces both stimulant and depressant effects in humans. These two seemingly opposite effects are central to the understanding of much of the literature on alcohol abuse and misuse. Is alcohol a stimulant? Stimulants excite your nervous system and may boost your energy, while depressants slow down your nervous system and relax you. Some substances like alcohol have both stimulant and depressant effects.

Once a person’s blood-alcohol levels go above .05% to .055%, alcohol’s harmful effects begin to increase. Therefore, feelings of calm, happiness, and relaxation start to turn into irritability, depression, and disorientation. At around .08% to .09%, the sense of balance is off and motor skills are reduced. Some individuals may also start vomiting at this level because of the excess alcohol in the blood and the human body’s inability to process the alcohol fast enough. In the United States, a person is considered to be legally intoxicated and forbidden from driving a vehicle if their BAC level is 0.08% or greater.

What is it used for?

A blood alcohol test may be used to find out if you:

  • Have been drinking and driving. In the United States, .08 percent blood alcohol level is the legal alcohol limit for drivers who are aged 21 and over. Drivers younger than 21 are not allowed to have any alcohol in their system when driving.
  • Are legally drunk. The legal alcohol limit for drinking in public varies from state to state.
  • Have been drinking while in a treatment program that prohibits drinking.
  • Have alcohol poisoning, a life-threatening condition that happens when your blood alcohol level gets very high. Alcohol poisoning can seriously affect basic body functions, including breathing, heart rate, and temperature [4].

Binge drinking can cause alcohol poisoning. Binge drinking is a pattern of drinking that raises the blood alcohol level within a short period of time. Though it varies from person to person, binge drinking is usually defined as four drinks for women and five drinks for men in a two-hour period.

Why do I need a blood alcohol test?

You may need a blood alcohol test if you are suspected of drunk driving and/or have symptoms of intoxication. These include:

  • Difficulty with balance and coordination
  • Slurred speech
  • Slowed reflexes
  • Nausea and vomiting
  • Mood changes
  • Poor judgment

You or your child may also need this test if there are symptoms of alcohol poisoning. In addition to the above symptoms, alcohol poisoning can cause:

  • Confusion
  • Irregular breathing
  • Seizures
  • Low body temperature

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Factors That Affect the Rate That Alcohol Is Processed

Alcohol is processed by the body at a constant rate, but some people may feel the effects of alcohol for a longer period of time. That’s because blood alcohol concentrations (BAC) can vary among people for a variety of the following reasons:


The older someone is, the longer alcohol lingers in the liver before it moves into the general bloodstream. Therefore, increasing the length of intoxication and risk of liver damage. In addition, the amount of water in the body also goes down with age, contributing to a higher blood alcohol concentration. An older person is more likely to be taking medication, and this concerns the liver as well. All of these factors mean that alcohol is metabolized at a slower rate.

Biological Sex

Because of several physiological reasons, alcohol is metabolized differently by men than it is by women. Alcohol stays in a woman’s system longer. This is because, in general, women tend to have a higher percentage of body fat and a lower percentage of body water compared to men. 

This means that a man’s body will automatically dilute the alcohol more than a woman’s, even if the two people are the same height and weigh the same amount. Hormone levels also affect the body’s ability to metabolize alcohol, and women will experience higher BACs drinking alcohol right before menstruation. Research has shown that women have less acetaldehyde dehydrogenase, the enzyme used to process alcohol in the stomach.


Eating a meal and having food in the stomach before drinking can have an important impact on the absorption rate of alcohol. Food helps dilute the alcohol and slow the emptying of the stomach into the small intestine, where alcohol is quickly absorbed. Maximum blood alcohol concentration could be as much as three times higher in a person with an empty stomach than in someone who has consumed food before drinking. Eating regular meals and having snacks while drinking can help influence enzyme activity in the liver and slow the rate at which alcohol is absorbed.

Body Size

An individual’s body size and composition are also factors that can affect how fast alcohol is processed. Low-water fatty tissue cannot absorb alcohol to the extent that high-water muscle tissue can, meaning someone with more body fat generally have higher blood alcohol concentration (BAC). Correspondingly, a person that is extremely muscular but of shorter stature will have a higher BAC than someone taller than them of the same composition.


Certain drugs can interact with alcohol and affect the metabolism, thereby influencing how the body is able to break down alcohol. Some medications slow the emptying from the stomach into the small intestine and liver, causing the alcohol to be quickly absorbed. This results in higher BAC levels and intoxication that affects the body more quickly.

Medications that are specifically known to interact with alcohol include:

  • Anti-anxiety medications such as Xanax
  • ADHD medications like Adderall
  • Cough and cold medicines
  • Diabetes medications such as Chlorpropamide

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Tips on How to Keep a Low Alcohol Blood Concentration

  • Take drinks with a low percentage of alcohol. For instance, choosing a low percent drink like a light beer instead of one with high percent alcohol like vodka or gin can minimize the BAC rate.
  • It’s recommended to stick to one alcoholic drink per hour.
  • Have a snack or eat a meal, preferably a protein-rich meal, before or while you are drinking. Pairing alcohol with food can slow its absorption and reduce its effects.
  • Drinking an extreme amount of alcohol in a short time is called binge drinking. It’s advised to avoid binge drinking because those who binge drink have higher BACs. It also takes longer for the alcohol to metabolize.
  • Rather of gulping or chugging your alcoholic drinks, it’s better to sip it slowly. The longer you take to consume one drink, the lower the BAC in an alcohol test.
  • Choosing a non-alcoholic drink is an alternative way to give your body time to break down the alcohol. You could also alternate between alcohol and water as this can reduce the absorption rate. Drinking water also keeps you hydrated.
  • Exercise and have an active lifestyle, so your body can eliminate the alcohol from your body quicker. Those who are active and have a higher metabolic rate can process and alcohol faster.
  • Always ensure that you are not driving after drinking. Breastfeeding mothers should avoid nursing for two to three hours for each drink they’ve had as alcohol interferes with the baby’s sleep and development. Pregnant women should avoid alcohol altogether.

Finding the Next Level of Treatment At We Level Up NJ

So, how long does alcohol stay in your blood? The effects of alcohol can vary from person to person, but one thing’s for sure, alcohol abuse can have harmful effects on your life. And long-term substance abuse (including drinking) can cause permanent damage to the brain and body. If you’ve tried to quit in the past but ended up drinking or using, that’s a clear sign you need professional help. Get them the safest help they need and deserve. Our team at We Level Up NJ specializes in creating an ideal environment and providing effective therapies.

How Long Does Alcohol Stay In Your Blood
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[1] DEA –

[2] NCBI –

[3] NIAAA –

[4] NIH –

[5] We Level UpAlcoholism Treatment