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What is diabetes?

Find important information about type 1 and type 2 diabetes and get connected to personalized support.

How diabetes affects the body

When you eat, some of your food is broken down into a type of sugar (also called glucose). This sugar travels in your blood to fat and muscle cells in your body, where it is needed for energy. A hormone made in the pancreas, called insulin, helps sugar move from your blood into your cells.

Diabetes is a disorder in which the body has trouble with insulin. Without insulin, glucose builds up in the blood, causing high blood sugar. High blood sugar can lead to other health problems.

An autoimmune disorder where your body makes little or no insulin because your immune system has attacked insulin-producing cells in your pancreas.


5% to 10% of adults with diabetes have type 1.


Treatments must include long-acting (basal) and mealtime (bolus) insulin therapy.

A metabolic disorder that prevents your body from producing enough insulin and also makes your body more resistant to the insulin that is produced.


90% to 95% of adults with diabetes have type 2.


Treatments may include insulin.

Long-acting insulin vs rapid-acting insulin

Different kinds of insulin work for different lengths of time:

Long-acting (basal) insulin lowers blood sugar throughout the day and may be taken to manage blood sugar for many hours and overnight.

Learn about one long-acting insulin »

Rapid-acting (bolus) insulin, also called mealtime insulin, helps control your blood sugar when taken as prescribed.

Learn about one rapid-acting insulin »

How do these 2 types of insulins work together?

Bodies usually release insulin:

  • In a steady “basal” amount throughout the day and night
  • In “bolus” bursts to control blood sugar spikes when you eat

Basal-bolus therapy is the combination of long-acting insulin with short-acting or rapid-acting insulin, which more closely mimics how the body’s natural insulin works throughout the day.

Understanding low blood sugar

The goal of any diabetes treatment is to lower blood sugar. However, it is possible for your blood sugar to drop too low. Ask your health care provider what blood sugar level is considered low for you.

If you are taking insulin, you should know the symptoms of low blood sugar (also called hypoglycemia):

  • Sweaty
  • Hungry
  • Confused
  • Shaky
  • Lightheaded
  • Dizzy
  • Sleepy
  • Nervous

These are not all the possible symptoms of low blood sugar. Talk to your health care provider to get a complete list of symptoms.

Severe low blood sugar

If these symptoms go untreated, low blood sugar can become severe. People having a severe low blood sugar episode (or severe hypoglycemia) may require assistance from another person for recovery. Severe low blood sugar may lead to seizures and loss of consciousness.

Learn which numbers are important as you manage your diabetes