What are the effects of alcohol – and how quickly is it broken down?

Many people find the effects of a little alcohol pleasant. But the effects can soon become unpleasant as your blood alcohol levels rise – especially if you already feel unsettled, sad or angry. “Pleasant” can also turn into “unwell”: most people feel sick after too much alcohol. The risk of accidents or of doing things you might later regret also increases the more drunk you are. In the long term, alcohol can harm the organs because it is a toxin (poison) that can damage cells.

What are the short-term effects of alcohol?

Different phases of drunkenness can be determined according to blood alcohol content.

Blood alcohol content Effect on mood and behavior Risks and physical effects
Up to 0.03%
  • Feeling of relaxation
  • Poor judgment of distances, for instance while driving
  • Slightly impaired judgment possible
Over 0.03% (tipsy)
  • Cheerful mood
  • Talkative and sociable
  • Increasingly impaired judgment
Over 0.05 % (slightly drunk)
  • Euphoric mood
  • Lowered inhibitions
  • Inappropriate behavior
  • Difficulty concentrating
  • Increasingly irritable
  • Danger due to coordination problems, reduced vision and hearing
  • Danger due to increasingly argumentative behavior and lack of insight
Over 0.08% (drunk)
  • Severe concentration problems
  • Loss of balance
  • Increasing overconfidence and lack of inhibitions
  • Dangers aren't correctly identified or assessed, or are ignored
  • Risk of accidents due to loss of balance, significantly reduced reaction times and numbed senses (tunnel vision, loss of hearing)
Over 0.1 to 0.2% (very drunk)
  • Slurred speech
  • Lack of restraint
  • Mood swings
  • Severely impaired reaction times
  • Severely impaired senses
Over 0.2 to 0.3% (stupor)
  • Body is severely intoxicated
  • Uncontrolled movements
  • Lack of reaction
  • Onset of alcohol poisoning with nausea and vomiting
  • Loss of memory
Over 0.3%
  • Unconsciousness
  • No reflexes
  • Coma and extremely slow breathing
  • Life-threatening condition

The effects of alcohol depend not only on how much alcohol is in your blood, but also on personal factors such as whether your body is used to it and your general current mood. Teenagers in particular react more sensitively to alcohol because they are still growing. Alcohol can also harm young people's organs more easily, which can permanently affect their development. Older people may react more strongly to alcohol too, for instance if they are taking medication or have chronic diseases.

What long-term physical damage does alcohol do?

Alcohol is carried in the bloodstream to the organs and body tissue, where it increases the risk of various diseases. These include cancers, cardiovascular diseases, and metabolic and digestive diseases such as gout and inflammations of the stomach lining, the pancreas and the liver.

The harmful biochemical processes that take place due to drinking alcohol include:

  • the breakdown of alcohol into acetaldehyde – a substance that can damage our DNA and cause cancer
  • increased production of “free radicals” – byproducts of oxidation processes that can damage cells
  • decreased absorption of various important nutrients, such as vitamins and

The fermentation and distillation processes used to make alcoholic drinks can result in harmful substances such as nitrosamines and phenol. These chemicals are also formed when tobacco is burned, and are part of the reason why smoking is harmful.

How is blood alcohol content (BAC) determined?

The amount of alcohol in our body is usually described as a percentage.

  • A blood alcohol content of 0.1% means that there are 0.1 grams of alcohol per 100 milliliters of blood.
  • In Germany and some other countries, the alcohol content is measured per 1,000 milliliters (per mil) instead. So 0.1 percent is the same as 1 per mil.

It is not possible to say what somebody’s blood alcohol content would be after drinking half a liter of beer. That will depend on various factors, such as the amount of water in their body, which is greatly influenced by their sex and body weight.

Various websites offer online blood alcohol content calculators that can be used to roughly work out your blood alcohol content.

How quickly does the body absorb alcohol?

Alcohol is mainly absorbed through the stomach. It takes 3 to 5 minutes for alcohol to pass through the blood to the brain, where it takes its effect. After around 30 to 60 minutes, it has spread throughout the body in the bloodstream. The effect is quicker if you drink on an empty stomach or after doing exercise, if you drink fast, or are ill. Certain medications can also influence the effects of alcohol.

How long does it take to sober up again?

Our bodies only break alcohol down slowly:

  • Women break down around 0.01% in an hour.
  • Men break down between 0.01% and 0.02% per hour.

Apart from the amount of alcohol you drink, the main factors that influence how quickly alcohol is broken down are your body weight and your sex.

For example, a small glass of wine (125 ml) is broken down

  • in about two to three hours in a woman who weighs 55 kilos (8.7 stone), and
  • in one to two hours in a man who weighs 80 kilos (12.6 stone).

It is not possible to speed up the process. But it's important to drink plenty of water or other non-alcoholic drinks because alcohol removes liquid from the body, so it has to be replaced.

Why are the effects of alcohol stronger in women than in men?

Women have a higher body fat content than men, but their bodies also contain less water. Because alcohol dissolves better in water than in fat, it is less concentrated in men’s blood than in women’s. The same amount of alcohol therefore makes women get drunk faster than men.

Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), Deutsche Gesellschaft für Psychiatrie und Psychotherapie, Psychosomatik und Nervenheilkunde (DGPPN), Deutsche Gesellschaft für Suchtforschung und Suchttherapie (DG-Sucht). S3-Leitlinie: Screening, Diagnose und Behandlung alkoholbezogener Störungen. AWMF-Registernr.: 076-001. 2020

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Created on November 9, 2021
Next planned update: 2024

Publisher:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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