When does alcohol become harmful?

Photo of an older woman
PantherMedia / Michael Möller

Lots of people wonder in what quantities alcohol becomes harmful. In Germany, different upper limits for the amount of alcohol that is considered to be low-risk are recommended for men and women. Current studies have found slightly different results.

It's not easy to precisely analyze the health effects of alcohol because alcohol can have a negative impact on many different organs in our body and various parts of life. Recommendations for low-risk drinking vary from country to country. The German Office for Addiction Issues recommends

  • drinking no alcohol on at least two days per week.
  • that women drink no more than 12 grams of alcohol per day, i.e. no more than a small glass of wine (125 ml). This amounts to 60 grams spread across one week with two alcohol-free days.
  • that men drink no more than 24 grams of alcohol per day, i.e. two small glasses of beer (600 ml). This amounts to 120 grams spread across one week with two alcohol-free days.

Two large international groups of researchers looked into the effects that alcohol has on our health. They concluded that

people who on average drink less than 100 grams of alcohol per week do no or little damage to their health. 100 to 200 grams of alcohol per week shorten life expectancy by an average of half a year; 200 to 350 grams of alcohol by two years; and over 350 grams by five years. No difference was found here between men and women.

Please note that these study results apply to healthy adults. It is important that people who have been treated for alcohol dependency and no longer drink stay away from any alcohol. The risk of relapse is otherwise very high. It is also advisable for people with other addictions not to drink any alcohol because they could be vulnerable to alcohol addiction.

What did the studies look into?

One of the two teams of researchers looked at how alcohol affects cardiovascular (heart and blood vessel) diseases and life expectancy. They evaluated the results of over 80 studies involving around 600,000 adults.

The other group analyzed the effects of alcohol on 23 diseases, including cardiovascular diseases, various types of cancer, and diseases of the digestive organs, along with injuries resulting from alcohol-related traffic accidents and other accidents. Overall, the team of scientists evaluated the results of almost 600 studies involving 28 million adults.

What were the results of the two studies?

Regarding life expectancy, the two studies found that alcohol reduces life expectancy – more significantly the more you drink. The table summarizes these results in figures. It shows how different quantities of alcohol impact the average life expectancy of a 40-year-old person.

Alcohol volume per week Impact on life expectancy
less than 100 grams (e.g. 2.5 liters of beer or 1 liter of wine per week) no or only slight reduction
100 to 200 grams (e.g. 2.5 to 5 liters of beer or 1 to 2 liters of wine per week) reduced by six months
200 to 350 grams (e.g. 5 to 9 liters of beer or 2 to 3.5 liters of wine per week) reduced by two years
more than 350 grams (over 9 liters of beer or 3.5 liters of wine per week) reduced by five years

Alcohol increases the risk of the diseases and accident effects that were studied almost across the board. Again, the more you drink, the greater the risk. Expressed in numbers, the studies found the following:

Average quantity of alcohol per day Number of people who become ill or have an accident within 10 years due to alcohol
No alcohol
10 grams 4 out of 10,000
20 grams 63 out of 10,000
50 grams 338 out of 10,000

In other words, people who on average drink a maximum of 10 grams of alcohol per day do hardly any damage to their health. The risk of disease or accidents already begins to increase at between 10 and 20 grams of alcohol per day. People who drink significantly more than 20 grams per day are considerably damaging their health.

It is also important to bear in mind that these statistics are estimates over a period of ten years. The risks of becoming ill are greater when a longer period of 30 to 40 years is considered.

What remains unanswered?

Neither study looked closely at the mental and social problems that alcohol can cause. High alcohol consumption can lead to depression and other mental disorders, and to conflicts in relationships, families and at work.

The effects of spreading out alcohol consumption are also not clear. For example, whether somebody drinks 40 to 50 grams two days per week or a maximum of 10 to 20 grams but every day could be of significance. The scientific analyses don't provide any information on this.

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.

GBD Alcohol Collaborators. Alcohol use and burden for 195 countries and territories, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet 2018; 392(10152): 1015-1035.

Wood AM, Kaptoge S, Butterworth AS, Willeit P, Warnakula S, Bolton T et al. Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies. Lancet 2018; 391(10129): 1513-1523.

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 25, 2021
Next planned update: 2024

Authors/Publishers:

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

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