How Insulin Works to Regulate Blood Glucose

Insulin is like a key that opens up the locks on your body's cells so that glucose (blood sugar) can get inside and be used for energy.

Insulin Helps Glucose
Get Into Your Body's Cells

If the glucose can't get into your cells, it builds up in your blood stream. If left untreated, high blood glucose can cause long-term complications.


Additionally, when blood sugar reaches a certain level, the kidneys try to get rid of it through urine - which means that you'll need to urinate more often. Frequent urination can make you feel tired, thirsty, or hungry. You may also start losing weight. Read about the symptoms of diabetes.

Your body also gets energy from a complex sugar called glycogen, which is stored in your liver and muscles. The liver converts glycogen to glucose and releases it into your bloodstream when you're under stress and/or when you're extremely hungry. When enough insulin is present, muscles can use their glycogen for energy, but cannot release it directly into the blood.

In type 2 diabetes, the liver releases too much glucose, especially at night (when the liver normally releases some glucose), resulting in high blood sugar levels in the morning. Insulin injections help bring down the amount of glucose released by the liver during the night, bringing morning blood sugars levels back to normal. Carbohydrates are broken down into glucose, which is the "fuel" that gives our bodies energy. Insulin's important job is to help glucose get into the body's cells.

Insulin Helps Build Muscle

When you've been sick or injured, or if you're recovering from surgery, insulin helps you heal by bringing amino acids (the building blocks of muscle protein) to your muscles. Amino acids repair muscular damage and help them regain their size and strength. If there isn't enough insulin in your body when your muscles have been injured, amino acids can't do their job, and your muscles can become very weak.

Learn about rapid-acting and long-acting insulins


The BD Diabetes Learning Center describes the causes of diabetes, its symptoms, and diabetes complications such as retinopathy and neuropathy. This site contains detailed information about blood glucose monitoring, insulin injection and safe sharps disposal. Interactive quizzes, educational literature downloads and animated demonstrations help to teach diabetes care skills.

Important Note: The content of this website is not intended to be a substitute for professional medical advice, diagnosis or treatment. Do not disregard your doctor's advice or delay in seeking it because of something you have read in this website.

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