How Does Insulin Control Diabetes?

Medically Reviewed By William C. Lloyd III, MD, FACS
Was this helpful?
60
Blood glucose meter

You can’t live without insulin. Every time you eat, your body releases insulin into your bloodstream. Insulin acts as a gatekeeper: Insulin tells your cells to let sugar in to carry out its many functions. Insulin also helps to maintain a healthy blood sugar level by removing excess sugar from your bloodstream. If you have diabetes, your body either can’t make insulin or your cells can’t respond to it properly.

How does insulin control type 1 diabetes?

If you have type 1 diabetes, the cells in your pancreas that make insulin don’t work because they’ve been destroyed by an autoimmune disease. Because your body can’t make insulin, it is unable to use the sugar in your blood to support your energy needs. Therefore, if you have type 1 diabetes, you must use insulin injections, also known as replacement insulin therapy, as part of your treatment.

How does insulin control type 2 diabetes?

If you have type 2 diabetes, your pancreas can still make insulin; however, there is not enough to maintain your body’s energy needs. In addition, your body’s cells are resistant to insulin. In other words, your body cannot use the sugar in your blood effectively.

If you have type 2 diabetes, you will most likely start treatment with oral medicines. With time, most people with type 2 diabetes find that oral medicines tend to lose effectiveness. If this happens, your doctor may recommend that you add insulin injections to your oral treatment. This is called augmentation insulin therapy. If augmentation therapy stops working well, your doctor may recommend that you change to replacement insulin therapy. In replacement insulin therapy, you use insulin injections alone to treat your diabetes. Some people with type 2 diabetes will start replacement insulin therapy right away. Either way, decisions to start insulin therapy should not be interpreted as bad news or some kind of defeat. It only means that insulin offers the best way to regain control over your diabetes.

Augmentation Insulin Therapy

In augmentation insulin therapy, you use insulin injections in addition to oral medicines to treat your type 2 diabetes. You use basal insulin in this type of insulin therapy. Basal insulin provides steady amounts of insulin. Depending on the specific product, basal insulin can last anywhere from 10 to 24 hours. Basal insulin includes:

Replacement Insulin Therapy

In replacement insulin therapy, you use insulin injections alone to treat your diabetes. You must use replacement insulin therapy if you have type 1 diabetes. You may also use it to treat type 2 diabetes. In replacement insulin therapy, you use two types of insulin, basal insulin and mealtime, or bolus insulin. Mealtime insulin provides short bursts (bolus) of insulin to cover the rapid rise in blood sugar levels after a meal. Mealtime insulin includes:

  • Aspart (NovoLog)

  • Glulisine (Apidra)

  • Lispro (Humalog)

  • Regular (Humulin R, Novolin R)

There are also combination products available. They contain a mixture of both basal insulin and mealtime insulin in one vial. Insulin mixtures include:

  • 70% aspart protamine/30% aspart (NovoLog Mix 70/30)

  • 50% lispro protamine/50% lispro (Humalog Mix 50/50)

  • 75% lispro protamine/25% lispro (Humalog Mix 75/25)

  • 50% NPH/50% regular (Humulin 50/50)

  • 70% NPH/30% regular (Humulin 70/30, Novolin 70/30)
Was this helpful?
60
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Apr 21
View All Diabetes Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

  1. National Institute of Diabetes and Digestive and Kidney Diseases http://diabetes.niddk.nih.gov/dm/pubs/medicines_ez/insert_C.aspx

  2. Insulin Replacement Therapy. University of Rochester Medical Center. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=85&contentid=P00344

  3. Blood Glucose Testing FAQs. Diabetes.co.uk.  https://www.diabetes.co.uk/blood-glucose/blood-glucose-testing-faqs.html

  4. What is Diabetes? The National Institute of Diabetes and Digestive and Kidney Diseases
    Health. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes