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How Long Does Alcohol Take To Leave Your System?

Alcohol is a beverage, which is a part of cultural practice in many countries. Some countries establish laws on the processes involving producing, selling and consuming it. How long does alcohol take to leave your system, is one of the common questions asked by many people.

While there are various health concerns and regulations related to alcohol consumption, many people are used to it. Be it a part of cultural practice or for any other reason, some people take it occasionally, while some regularly. Hence, there is always a concern regarding the effects of alcohol on our body and about how long it remains in the body.

How Long Does Alcohol Take To Leave Your System?

How Long Does Alcohol Take To Leave Your System?

The main constituent of alcohol is ethanol or ethyl alcohol. It can be produced by fermenting foods rich in sugar like fruits and grains. The effects on your body and the time that alcohol takes to leave your system depend on several factors. Alcohol and its residues are found in the blood and other tissues of humans. It takes some time to leave these organs. It is necessary to know how long does alcohol take to leave your system. It may vary mainly with the quality and the amount of alcohol taken.

How long alcohol takes to leave your system depends upon the quantity of drink you have consumed and how often you have been drinking. It also varies depending on the tissue or organ in which it is found. Normally, one drink stays for one hour. This is because the liver can metabolize approximately one drink in one hour. The alcoholic content is excreted through urine and from the records it is found that alcohol is confirmed even after 80 hours after consumption.1 Alcohol may also penetrate the hair follicles and stay there for 3 months.2,3

The Action of Alcohol on Human Body

People start drinking alcohol because it gives them feel intense pleasure or well being. The people who consume alcohol may also feel like reducing their stress and anxiety. Some people use it for recreation. Even though it is used to stimulate happiness in the beginning, gradually it makes you addicted to it. Intake of a large quantity of alcohol or drinking very frequently increases the risk of getting addicted to it. It can also affect major organs like the liver and the heart, apart from other problems like headaches, digestive troubles, and nerve issues. Extreme addiction can cause unconsciousness or even death.

Biochemical Reactions on Which Alcohol has its Effects

The metabolism of consumed alcohol starts when it reaches the stomach. Roughly 20% of alcohol is digested there. The major portion that is 80% of it moves to the small intestine which is then absorbed by the bloodstream. The liver breaks down the rest of the portion of alcohol but does how much it can. The remaining portion of alcohol is sent to all parts of the body through blood. The concentration of alcohol in the blood is measured by BAC (blood alcohol concentration) scale. This scale explains the percentage of alcohol found in the blood. According to this scale, people relax at 0.04, driving is affected at 0.08, feel vomiting usually at 0.12, lose consciousness from 0.30 to 0.40 and die at 0.45. According to the American Medical Association, a person can become impaired when the blood alcohol level hits 0.05.4

How long does alcohol take to leave your system also depends on the biochemical reactions in its metabolism in the body. The following are the important biochemical reactions involved in the metabolism of alcohol:

Ethyl alcohol (simply alcohol) is oxidized into acetaldehyde with the help of an enzyme and two hydrogen atoms are separated from the alcohol. This step is carried out by three different enzymes. They are alcohol dehydrogenase (ADH), CYP2E1 (cytochrome P450 2E1 and catalase. All these enzymes are found in different parts of the body.

ADH is mainly found in the stomach and liver in more quantity. This enzyme helps the metabolism of ethyl alcohol in light drinkers. This reaction takes place in the cytoplasm. On the other hand, CYP2E1 is activated in heavy drinkers. This enzyme is found in the liver by using energy in the form of NADPH.5 This reaction takes place inside the cells in microsomes. One more enzyme catalase which is found in peroxisomes of the cell all over the body converts alcohol into acetaldehyde. The hydrogen atoms released would be tagged with hydrogen peroxide molecules. These molecules are then transformed into water.

Another enzyme called acetaldehyde dehydrogenase helps in the conversion of acetaldehyde into a radical called acetyl radical (negatively charged). Here a hydrogen atom is separated. This acetate radical is then sent to the circulatory system.

Production of the excess of NADH from all the above reactions stimulates the conversion of pyruvic acid into lactic acid. An increase in the concentration of lactic acid leads to a condition called acidosis. Also, the production of glucose from amino acids, which is generally called gluconeogenesis is affected leading to hypoglycemia. Heavy drinkers are also at greater risk of fatty liver, as it processes large quantities of alcohol. It can also lead to weight gain, obesity, and high cholesterol. Some of the lipids are liberated from the bloodstream, which increases the risk of cardiac arrest.


Alcohol consumption is best avoided in all circumstances. Considering how long alcohol takes to leave your system if, at all taken, it should be occasionally and in limited quantity. If at all alcohol is consumed, the level of BAC should be kept to a minimum range. Care has to be taken to prevent the entry of alcohol to the bloodstream and to the urinary bladder. The addiction may bring socio-economic problems to the families of the person who is addicted. The person if addicted would neither be healthy nor would the environment he/she lives be healthy. In case if the person is suffering from any disorder, alcohol consumption can affect the blood test and the treatment. Instead, the overconsumption of alcohol is a risk factor for several diseases. Hence it is best to prevent a person from drinking alcohol.


  1. https://www.addictioncenter.com/alcohol/how-long-is-alcohol-in-your-system/
  2. Substance Abuse and Mental Health Services Administration. (2006). Substance Abuse: Clinical Issues in Intensive Outpatient Treatment.
  3. American Society of Addiction Medicine. (2013). Drug Testing: A White Paper of the American Society of Addiction Medicine.
  4. http://chdtransport.gov.in/Webpages/DrunkenDriving.html
  5. “Venipuncture – the extraction of blood using a needle and syringe”. Retrieved June 21, 2012.

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:March 25, 2021

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