Type 1 diabetes

At a glance

  • In type 1 diabetes, the body doesn't make any insulin.
  • Insulin is a hormone that regulates your metabolism. You need it to live.
  • The disease usually starts in childhood or puberty.
  • It can cause various symptoms and lead to damage over time – for instance, affecting the kidneys or eyes.
  • People who have type 1 diabetes have to inject insulin and check their blood sugar levels every day.


Photo of a boy

Diabetes is a metabolic disease that affects many parts of the body. Depending on the type of diabetes, the body either can't produce insulin itself (type 1) or it is unable to properly use the insulin it produces (type 2). Insulin is a hormone – a chemical messenger that is transported in the blood and regulates important body functions. Without insulin, your body can't get the energy it needs from the food you have eaten.

This vital hormone is usually produced in the pancreas and released into the bloodstream. It enables the sugar (glucose) in our food and drink to be transported into our cells and converted into energy for our bodies. Without insulin, our bodies can't use the sugar in our blood, so the sugar builds up there. Very high blood sugar concentrations cause a number of symptoms.

People with type 1 diabetes have to inject insulin every day because their can only produce very little insulin, or none at all. Insulin therapy helps to prevent strong fluctuations in blood sugar levels and the unpleasant short-term effects of high and low blood sugar. Another aim is to prevent health problems that may develop over time as a result of high blood sugar levels.

Illustration: Insulin molecules and position of the pancreas


If type 1 diabetes isn't treated effectively, the blood sugar levels are always too high. This isn't always immediately noticeable. But very high blood sugar (hyperglycemia) can cause the following problems:

  • Having to pee often
  • Extreme thirst
  • Tiredness and listlessness
  • Nausea
  • Dizziness

If someone has extremely high blood sugar levels, they may feel confused and drowsy or even lose consciousness (diabetic coma).

Causes and risk factors

Insulin is produced in special cells in the known as beta cells. In people who have type 1 diabetes, the beta cells are attacked by their own immune system. Over the years these cells become so damaged that they only produce very little insulin, or none at all.

Type 1 diabetes is more common in certain families. This means that some people have a higher risk of developing diabetes because of their genes. Other things are believed to play a role too, for example particular infections or environmental factors. But it is not clear what exact role they play.

Prevalence and outlook

About 200,000 people in Germany have type 1 diabetes. About 30,000 of them are children and teenagers under the age of 19. Every year about 2 out of 10,000 children develop type 1 diabetes.

Because it usually starts in children, teenagers or young adults – and only rarely in older people – type 1 diabetes is also called “juvenile” (young) diabetes.

If left untreated, type 1 diabetes can soon lead to problems. Very high blood sugar causes typical symptoms like thirst, frequent urination (peeing often) and . These symptoms can quickly be relieved with insulin. Diabetic coma due to extremely high blood sugar levels is very rare nowadays. Before insulin therapy was introduced in 1922, it was an unavoidable consequence of the disease, leading to death. As a result, people who developed type 1 diabetes did not live long.


Blood sugar levels that are very high over many years can have serious and irreversible health consequences. The complications and damage arising from poorly controlled diabetes may affect many organs. The small blood vessels that supply the tissue become damaged.

Over time, the tiny blood vessels in, for instance, the retina of the eye (diabetic retinopathy) or kidneys (diabetic nephropathy) can become so damaged that the person affected might go blind or have kidney failure. Another common diabetes-related problem is known as diabetic neuropathy, which attacks the nerves. It affects the sense of touch and the ability to feel temperature and pain. This can lead to the development of wounds because people might not notice sore areas and small injuries. These wounds often don't heal well because of the poor blood supply.

High blood sugar levels can damage larger blood vessels too. That increases the risk of heart attacks and strokes.


To find out whether someone has diabetes, their blood sugar levels are measured before their first meal of the day and then again during the day. Several samples of blood are taken in a doctor’s practice and sent to a laboratory to be tested. To see whether someone’s blood sugar levels have been too high over a longer period of time, something known as the HbA1c value is measured. This value indicates how high your blood sugar has been on average in the last two to three months.


In type 1 diabetes, the focus of treatment is to monitor blood sugar levels every day and regularly use insulin. Insulin therapy makes up for the lack of insulin in the body and lowers the concentration of sugar in the blood. It is important not to use too much or too little insulin, otherwise the blood sugar levels will get too low or too high.

The typical symptoms can largely be avoided through good treatment. The treatment also aims to prevent long-term complications caused by diabetes. There are different types of insulin and different treatment approaches.

Your blood sugar levels aren't only affected by the amount of insulin you inject but also by what you eat and drink, as well as how much energy you use during physical activity. The time of day, inflammatory diseases, other medications or hormonal changes can influence your blood sugar levels too. So most people learn to finely adjust their insulin therapy according to their own body and personal habits. Devices such as insulin pumps or continuous glucose monitoring (CGM) systems can help here.

In order for treatment to be successful, people need to be well informed about their diabetes, manage their own therapy effectively and have reliable medical care. But over the long term, your general health will depend on other things besides just blood sugar levels. Aspects like blood pressure can have a big effect in diabetes. Because of this, people with diabetes often take other medications as well as insulin, for example to prevent cardiovascular disease.

Everyday life

Although there is currently no cure for diabetes, it is possible to lead an almost normal life with the disease. There were times when people with diabetes had to lead strictly regulated lives. For example, they had to wait a certain amount of time between injecting insulin, eating and doing physical activity. Insulin therapy has now become much more flexible.

Nowadays, people who have diabetes can largely decide for themselves what kind of treatment they would like and how to fit it into their daily lives. Diabetes no longer dominates all aspects of their lives.

But managing diabetes still involves a good deal of effort, care and discipline. That isn't always easy and can sometimes be quite a burden, especially for younger people. Just like most people who have a chronic condition and have to take medication every day, those with diabetes might forget to inject insulin or take their medication every now and then. People who don't follow their treatment plan properly often feel quite normal and don't necessarily notice that their blood sugar levels are poorly controlled. But this can lead to serious health problems in the long term.

Further information

When people are ill or need medical advice, they usually go to see their family doctor or pediatrician first. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your visit to the doctor.

There are many sources of help for people with type 1 diabetes in Germany. These include support groups and information centers. Support services are often organized quite differently from region to region, though. Our list of places to contact may help you to find and make use of the help you need.

You can find more information related to diabetes at the diabetes information portal diabinfo.de.

Deutsche Diabetes Gesellschaft (DDG). Diagnostik, Therapie und Verlaufskontrolle des Diabetes mellitus im Kindes- und Jugendalter (S3-Leitlinie). AWMF-Registernr.: 057-016. 2015.

Deutsche Diabetes Gesellschaft (DDG). S3-Leitlinie: Therapie des Typ-1-Diabetes. AWMF-Registernr.: 057-013. 2018.

DiMeglio LA, Evans-Molina C, Oram RA. Type 1 diabetes. Lancet 2018; 391(10138): 2449-2462.

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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Updated on December 8, 2021

Next planned update: 2024


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

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