How insulin affects blood sugar

Insulin is a hormone made naturally in the pancreas that helps move sugar into the cells of your body. Your cells use the sugar as fuel to make energy.

Without enough insulin, sugar stays in your bloodstream, raising your blood sugar. High blood sugar, or hyperglycemia, can lead to the signs and symptoms of diabetes:

  • Feeling extreme thirst or hunger
  • Needing to go to the bathroom more often
  • Blurry vision

Over time, hyperglycemia can damage your nerves, eyesight, and kidneys, so it’s important to get your blood sugar in the target range recommended by your health care provider. Insulin therapy can help control blood sugar.
 

Different types of insulin meet different needs 

When you have diabetes, you either do not have enough insulin in your body to control your blood sugar or your body prevents the insulin it does make from working properly. Your health care provider may start you on a man-made insulin that can help control your blood sugar during the times of the day that you need it most.

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. Your diabetes care team will prescribe the insulin that is best for you.
 

Different insulin treatments are grouped by how long they work 

Type of insulin Onset Duration
Long-acting 1 hour Up to 24 hours
Rapid-acting 10-30 minutes Up to 5 hours
Premixeda 10-30 minutes Up to 24 hours

aPremixed insulin combines specific proportions of a long-acting insulin with insulin that provides coverage for a meal in one vial or insulin pen. (The numbers following the brand name indicate the percentage of each type of action.)

  • Long-acting (basal) insulin. Long-acting insulin like Levemir® works to control blood sugar between meals and when you sleep. Long-acting insulin is taken once or twice daily at the same time each day (often with your evening meal or at bedtime) to help give you up to 24-hour blood sugar control. This is likely the first type of insulin your health care provider will prescribe for you if you have type 2 diabetes
  • Rapid or fast-acting (bolus) insulin. Fast-acting insulin is taken near mealtime. This insulin works quickly to control the rapid spike in blood sugar with meals and imitates the body’s natural release of insulin
  • Premixed insulin. Premixed insulin combines the action of fast-acting and long-acting insulin. For example, a 70/30 mix means 70% has an extended action for when you are not eating (fasting), and 30% acts fast for mealtime coverage
     

Long-acting insulin can be taken along with rapid-acting insulin 

When you need more control over your blood sugar, your health care provider may suggest basal-bolus therapy. Basal-bolus therapy is recommended for people with type 1 diabetes. It may also be recommended for people with type 2 diabetes who need tighter blood sugar control.

People on basal-bolus therapy monitor their blood sugar closely and take insulin doses with meals and prior to bedtime. The goal of this kind of insulin therapy is to mimic the way blood sugar is controlled in your body.

Basal-bolus is one of the combination treatment plans that Levemir® long-acting insulin can be a part of to help you meet your blood sugar goals.

Learn more about Levemir®