New research shows that the caffeine added to these drinks can place a strain on the heart and blood vessels and disrupt sleep. What happens to the body after years of regular consumption, scientists as yet know almost nothing. For this reason the Federal Institute for Risk Assessment (BfR) has updated its risk assessment and now draws on several recent scientific studies.
Many teenagers drink energy drinks regularly
Researchers analysed data on more than 100,000 children and adolescents. Among teenagers aged 13 to 15, the results were as follows:
- 71.7 percent had tried energy drinks at least once;
- 19.2 percent drink them at least once a week;
- 6.1 percent drink them daily or almost daily.
Put in terms of proportions, roughly one in five teenagers of this age drinks energy drinks every week, and roughly one in sixteen does so almost every day.
In the view of Reiner Hanewinkel, advertising and social media contribute to the spread of this habit. Hanewinkel works on prevention and heads the Institute for Therapy and Health Research (IFT-Nord). Bloggers show energy drinks in their posts so casually that it is hard for a teenager to notice that he is looking at an advertisement. Bloggers also play on teenagers’ weaknesses and restrictions: they always bring up the ban on tobacco and alcohol for teenagers, explaining that there is a legal alternative to “adult doping”, and in this way they push energy drinks, nicotine pouches and snus on teenagers. Teenagers do not realise that bloggers make money from this, and place complete trust in “internet windbags”.
Two small cans can contain too much caffeine
A simple calculation is enough to judge whether this is a lot or a little. For children and adolescents, a caffeine dose of up to three milligrams per kilogram of body weight is considered safe. A teenager weighing 50 kilograms, therefore, can take in no more than 150 milligrams of the substance per day. “A 250-millilitre can of an energy drink contains about 80 milligrams of caffeine, and two small cans are already enough to take a teenager beyond the point where benefit turns into harm to the body,” explained Anke Ehlers of the BfR.
Meanwhile, two cans a day are far from the limit for some teenagers. The EDKAR study states that 11 percent of respondents said that on some days they drink more than a litre of energy drinks (some energy drinks are sold only in half-litre cans at the smallest, attracting teenagers with distinctive sweet flavours). With the same caffeine content, a litre of the drink is twice the safe daily dose for a teenager weighing 50 kilograms. The lower a person’s weight, the lower the permissible dose of caffeine, so for younger teenagers the boundary between benefit and harm lies lower still.
German law also limits the caffeine content of energy drinks. By law, a litre of such a drink may contain no more than 320 milligrams of caffeine. Manufacturers, as a rule, use this limit in full, Ehlers notes. High caffeine consumption is not necessarily accompanied by complaints, since sensitivity to it varies from person to person. Beyond the safe limit, however, the uncertainty about the future of a body that has not yet matured grows, and the risk of undesirable effects rises with the daily dose.
Strain on the heart, circulation and sleep
“Blood pressure rises,” noted Felix Oberhoffer of the University Hospital of Ludwig Maximilian University of Munich. This was the conclusion of the EDUCATE study, in which he examined the short-term effects of energy drinks on children and adolescents. Participants were given a moderate amount of the drink, calculated according to their weight. The researchers then checked blood pressure, heart rhythm and heart function.
It is important that this work shows the body’s reaction shortly after consuming the drink, not the consequences of many years of consumption. Disturbances of heart rhythm and sleep, according to Oberhoffer, are possible even with comparatively small quantities of the drink. Large doses are especially dangerous before sport, in combination with alcohol, and in conditions such as high blood pressure or congenital heart defects.
Long-term consequences remain unclear
The EDKAR study sought to establish what can be expected from constant and unlimited consumption of energy drinks. Adolescents with a high level of consumption of this type of drink were compared with a control group. High consumption was defined as cases in which an adolescent had drunk energy drinks on at least four days a week for at least twelve months and received more than three milligrams of caffeine per kilogram of body weight a day. The control group makes it possible to understand whether such a habit really changes the functioning of the body.
No differences between the two groups were found in indicators of heart and circulatory function. However, adolescents with a high level of consumption complained of a racing heartbeat, nervousness and feeling unwell. The BfR stressed that far too little is still known about the long-term consequences of drinking energy drinks. It is difficult to study, because for ethical reasons children and adolescents cannot be given large quantities of energy drinks over a long period.
Oberhoffer sees cause for concern even without these data, since the short-term effects already worry him. Raised blood pressure may cause no complaints for a long time, yet it can damage the cardiovascular system for years and later increase the risk of heart attack or stroke.
What parents can do
Oberhoffer advocates stronger protection of minors. He proposes, for example, allowing the purchase of energy drinks only from the age of 16. He presented this idea in 2024 to the Bundestag‘s committee on food and agriculture.
Hanewinkel also expects rules to be set for advertising (not only offline) and sales, but places his main emphasis on everyday prevention among parents and teenagers. Parents should know what their children are involved in and maintain a conversation with them, including about what they drink and how much. In Hanewinkel’s opinion: “Support for the family and parents, and their ability to give a child something to rely on, remain of enormous value and an almost universal means of prevention.”
Why this matters
Studies have already confirmed the short-term effect of energy drinks on teenagers’ blood pressure, heart rhythm and sleep. The long-term consequences of constant consumption of this type of drink remain little studied, for many moral and legal reasons. The EDKAR and EDUCATE studies complement each other: one shows how often and in what quantities teenagers drink energy drinks, the other shows how a teenager’s body reacts to an energy drink.
Until there are observations spanning many years of the effect of energy drinks, risk has to be assessed on the basis of what is already known about caffeine and the strain on the adolescent heart. For parents this means that what matters is not a single can but the total volume, the frequency of consumption and the circumstances, such as playing sport or combining the drink with alcohol. Specialists propose combining restrictions on advertising, including covert advertising, and on sales with the active involvement of the family in explanatory conversations. Restrictions may make energy drinks less accessible to minors in shops, but, as in the case of nicotine pouches and snus, black and grey markets immediately become active. And family involvement may perhaps help some teenagers to understand for themselves why they need, or do not need, an energy drink, and how much of such a drink they consume every day.
