What is Insulin?

Insulin is a hormone that is made in your body naturally. The pancreas, an organ near your stomach, releases more insulin each time there is a rise in blood sugar levels. Blood sugar levels usually rise after a person eats a meal. That's when the body takes the food you ate and turns it into sugar, sometimes called glucose.

The insulin in your body works like a key, unlocking cells to help deliver sugar from the blood. Every cell in the body has a lock on its cell wall, called a receptor. Insulin fits into that lock like a key, allowing sugar to enter the cells. When the body is not able to make enough insulin, blood sugar is locked out of the cells.

When blood sugar is locked out of cells, it stays in the bloodstream. This leads to blood sugar building up in the bloodstream until blood sugar levels are too high, which is also called hyperglycemia. This extra sugar is what makes people feel the symptoms of diabetes, such as often feeling tired or thirsty.

Types of insulin therapy

The first generation of man-made insulin, created in the 1980s, was called "human insulin." It is available in 3 types: regular human insulin, intermediate-acting, and premixed. More recently, analog insulin has been made. It works in a variety of different ways. Some types of analog insulin act more quickly, others more slowly.

Different types of insulin work differently to mimic the way the body normally releases insulin. They each have a different:

• Onset of action (when they start to work)
• Time of peak action (when their effect on blood sugar is greatest)
• Duration of action (how long they work)

A more recently developed type of insulin is called "analog insulin." Analog insulin is available in these types:

• Long-acting. This type works more slowly. It works longer to control blood sugar between meals and when you sleep. Long-acting insulin is taken either once or twice a day at the same time every day, often with your evening meal or at bedtime to help give up to 24-hour insulin coverage. This is often the first insulin prescribed by your doctor for type 2 diabetes
• Rapid or fast-acting. This type is taken shortly before mealtime. It works quickly to control the rapid rise in blood sugar after meals. Fast-acting insulin mimics the body's natural release of insulin at mealtime
• Premixed. For appropriate patients, premixed insulin combines the action of a rapid and long-acting insulin

Each type of insulin helps keep diabetes under control. But no one type is right for everyone. Each person's insulin need is different. And each person's insulin need may change over time.

Analog insulin is preferred by the American Association of Clinical Endocrinologists, or AACE. Your doctor and diabetes care team will prescribe the insulin that is best for you.

Taking insulin

The way you are able to take your insulin is constantly improving. For instance, there are insulin-delivery devices available that are prefilled with insulin. Devices like the NovoLog® FlexPen®, prefilled with NovoLog® insulin, are ready to use in just a few steps.