How Long Does Alcohol Stay in Your System?

What is Alcohol?

Alcohol is one of the world’s most popular substances of use and abuse. Almost everyone has heard of it, but what is it exactly, what does it do to your body, and how long does alcohol stay in your system? Alcohol is a depressant that slows down the central nervous system, causing a loss of motor coordination, and a decrease in reaction time and intellectual abilities. At high quantities, alcohol can cause your respiratory system to slow down to the point of a coma or death.

How Long Does Alcohol Stay in Your System for Testing?

How Long Does Alcohol Stay in Your System for Blood Testing?

Alcohol can be detected in your blood for approximately 12 hours.

How Long Does Alcohol Stay in Your System for Urine Testing

Alcohol can be detected in your urine for about 3-4 days after drinking.

How Long Does Alcohol Stay in Your System for Breathalyzers?

Alcohol can be detected on your breath for about 24 hours after drinking.

How Long Does Alcohol Stay in Your System for Hair Testing?

Alcohol can be detected in your hair for up to 90 days after drinking.

How Long Does Alcohol Stay in Your System for Saliva Testing?

Alcohol can also be detected in your saliva for 10-24 hours after drinking.

How Long Does Alcohol Stay in Your System for Breast-Feeding?

Alcohol can be detected in breast milk for as long approximately 12 hours.

How Long Does Alcohol Stay in Your System Biologically?

One of the main questions that people who consume alcohol may ask is, how long does alcohol stay in your system? While you might think that there is a straightforward answer to that question, it is actually quite complex. To understand how long it takes for the body to process alcohol, it is worth understanding the path that alcohol takes through your body and how it is broken down.

Are there many factors that affect the answer to how long does alcohol stay in your system? Yes! For example, if you drink more than that or drink on an empty stomach, you may still have alcohol in your system the following day which might still make it illegal for you to drive. Let’s learn about some of the most important factors.

How Much is Absorbed?

When you consume an alcoholic beverage, around 20% of the alcohol enters your bloodstream very quickly through the stomach. The small intestines absorb the remaining 80%. Any leftover alcohol that has not been metabolized leaves the body through sweat, urine, and saliva.

The Importance of Your Liver

Once the alcohol enters the bloodstream, it goes to the liver to be metabolized and broken down. The liver contains enzymes that break down alcohol molecules; however, if you drink alcohol too quickly, then the liver cannot process all the alcohol in time, and the alcohol remains in the body for longer. In general, the liver can process one ounce of alcohol (or one standard drink) every hour. This gives you part of the answer to how long does alcohol stay in your system?

Knowing the Strength and Quantity of Your Drink

It is important to be aware of what a standard drink is, to make sure that you are not drinking more alcohol than your liver can process. For context, one standard drink is equivalent to 12 ounces of 5% alcohol beer, 5 ounces of 12% wine, or 1.5 ounces of 40% hard alcohol such as vodka, tequila, rum, or whiskey. The quantity and strength of the drink are important when figuring out how long alcohol stays in your system?

Because different types of alcohol have different strengths (e.g., hard liquor has a higher alcohol content than beer), you have to be careful about how much of each type of alcohol you are drinking. Taking shots or playing drinking games, for example, typically leads to people drinking more than one standard drink an hour and therefore increasing their blood alcohol content drastically.

Your Blood Alcohol Content

Blood alcohol content (BAC) measures the ratio of alcohol in your blood. The ratio is part of the information needed to determine how long does alcohol stay in your system. For example, a BAC of 0.10 means one-part alcohol for every 1000 parts of blood. The higher your BAC, the more alcohol in your bloodstream, and the more you will feel the effects. This is important to know for both your health and safety, but also because it is illegal to drive if your BAC is over 0.08.

How Does BAC Affect the Presence of Alcohol in Your System?

When answering how long does alcohol stay in your system, you can assume that alcohol is eliminated from the body at 0.015 per hour. Someone who has a BAC of 0.08, which is the point at which it becomes illegal to drive, will need around 5.5 hours for the alcohol to flush out of their body.

Symptoms of High BAC Levels

At high BAC levels, it will take longer for the alcohol to get out of your system, and you may experience the following side effects:

  • Reduced inhibition
  • Impaired memory
  • Slurred speech
  • Confusion
  • Difficulty concentrating
  • Problems breathing
  • Nausea
  • Vomiting
  • Impaired balance/coordination
  • Irritability

Effects on Other Parts of Your Body

Although the majority of alcohol is metabolized in the liver, alcohol also affects all of the major organs, the brain, the heart, kidneys and even your skin. Heavy drinking can eliminate vitamins and minerals from your body, particularly vitamin B which can lead to a hangover where you feel sick and tired. Prolonged alcohol use can have adverse affects on health, particularly by damaging the liver. Some of the long term impacts of prolonged alcohol use include:

  • Mouth, throat, or breast cancer
  • Stroke
  • Heart disease
  • Liver disease
  • Brain disease
  • Nervous system disease
  • Accidents (such as from drinking and driving)

Alcohol and Breastfeeding

Breastfeeding mothers can receive conflicting advice about the effect of alcoholic consumption on a baby. Women are told not to consume alcohol during pregnancy because they can cause damage to an unborn child. The risks of drinking alcohol while breastfeeding, however, are not well defined.1

If you consume a large amount of alcohol while breastfeeding, this can cause deep sleep, drowsiness, weakness, and abnormal weight gain in a baby. There can also be a decrease in the amount of milk that a woman produces. You should also be careful to co-sleep with a baby after drinking since your reflexes can be impaired.2

In general, a breastfeeding mother can drink a reasonable but not excessive amount of alcohol.3 A woman should always consult her doctor to get the best advice on safe practices surrounding drinking alcohol while breastfeeding.

How Long Alcohol Stays in Your System is Affected by Many Factors


The older you are, the longer alcohol stays in your system. At an older age, your blood flow is likely to be slower, and you are more likely to be taking medications that impact the liver.


Typically, alcohol stays in your system longer if you are a woman. This is because women tend to have a higher body fat percentage than men and a lower percentage of water in their bodies.


Because alcohol is absorbed into your bloodstream through your stomach, the presence of food in the stomach can significantly increase how long alcohol stays in your system. More food in your stomach means that the alcohol will absorb into the bloodstream more slowly.


Because people of East Asian backgrounds sometimes lack the enzymes necessary to break down alcohol, it is fairly common for them to experience facial flushing, nausea, dizziness, rapid heart rate and headaches after drinking. The lack of enzymes will increase how long alcohol stays in your system.

Family History:

Alcohol use disorders tend to run in families, indicating that there is a genetic component to the abuse of alcohol. Genetics can either increase or decrease how long alcohol stays in your system.

Body Composition:

The size of your body can impact how you process alcohol. Someone who is smaller and lighter will be impacted more quickly by alcohol than someone with a bigger frame who is heavier. So, your body size can change how long alcohol stays in your system.

Time Since Last Drink:

The longer that you wait in between drinks, the shorter the time alcohol stays in your system. If you are drinking consecutive drinks, you are more likely to experience the effects of alcohol much more quickly since your liver can’t keep up with how much you have drank.


If you are taking anti-depressant medications, anti-anxiety medications, antibiotics, allergy medication or diabetes medications, it is typically advised that you do not mix these medications with alcohols as they can increase the effects of alcohol on the body. One of the effects that can be increased is how long alcohol stays in your system.


  2. Ibid.
  3. Ibid.