What does insulin do in my body?

One of insulin’s most important jobs is to help cells use glucose.

Insulin acts like a key to unlock the door that lets glucose into the cell. Cells in the body use glucose as a source of energy that they need to live. Without energy, the cells in the body cannot survive. Insulin also helps the body to store extra fuel as fat.

Insulin is a hormone made by the pancreas that helps the body store and use glucose.

Think of insulin as the U.S. Postal Service and glucose as the mail; insulin is responsible for delivering that glucose (sugar) from the bloodstream into muscle, fat, liver, and most other cells so that your body can use it for fuel.

I wish insulin had a similar mantra to the USPS-neither blood, not fat, nor DNA will keep insulin from delivering glucose throughout the body-but doesn't quite work that way. And problems happen either when the pancreas doesn't make enough insulin or because various parts of the body block insulin and prevent it from delivering glucose to those cells.

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)
Insulin controls the amount of sugar from digested foods circulating in your bloodstream, and allows cells to use the sugar for fuel or be stored for future needs. Watch the animation to learn the basics about insulin.
Kate Myerson
Nutrition & Dietetics Specialist
I like to think of insulin as being the key to a car. The car is our body and instead of gas we run on glucose. The gas gauge is like a blood glucose meter, we can run without it for a while but it is really useful for telling us when we are going to run out of energy. Without the key to the car (insulin) we are not going anywhere. We need insulin to use the sugar to give us energy. 

Continue Learning about Diabetes


Diabetes mellitus (MEL-ih-tus), often referred to as diabetes, is characterized by high blood glucose (sugar) levels that result from the body’s inability to produce enough insulin and/or effectively utilize the insulin. Diabetes ...

is a serious, life-long condition and the sixth leading cause of death in the United States. Diabetes is a disorder of metabolism (the body's way of digesting food and converting it into energy). There are three forms of diabetes. Type 1 diabetes is an autoimmune disease that accounts for five- to 10-percent of all diagnosed cases of diabetes. Type 2 diabetes may account for 90- to 95-percent of all diagnosed cases. The third type of diabetes occurs in pregnancy and is referred to as gestational diabetes. Left untreated, gestational diabetes can cause health issues for pregnant women and their babies. People with diabetes can take preventive steps to control this disease and decrease the risk of further complications.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.