Understanding the role ofinsulinand glucose (blood sugar) in the body is important part of managing type 2 diabetes. Insulin is a hormone that lowers blood sugar, preventing excess glucose from damaging cells. In type 2 diabetes, blood sugar is high due to having cells that do not take up enough sugar because they are resistant to insulin.
This article explains the role of insulin and its impact on blood sugar, and what happens when this process is dysfunctional.
Morsa Images / Getty Images
What Is Insulin?
Insulin was discovered in the early 1920s and over the next decades, developed into a lifesaving pharmaceutical product for people with diabetes.
What Is Blood Sugar?
Blood sugar, also known as blood glucose, is the concentration of sugar in the blood, typically given in units of milligrams per deciliter (mg/dL). The normal fasting blood sugar level is less than 100 mg/dL. However, indiabetes, this level is above 126 mg/dL. Numbers in between are considered in theprediabetesrange.
The body needs to maintain blood sugar within a specific range. When glucose is too low,hypoglycemiacan occur. In hypoglycemia, the brain doesn’t have enough energy, which can lead to coma and death unless treated.
Insulin Resistance and Diabetes
Treating High Blood Sugar With Insulin
Most available forms ofinsulinare injectable, delivered via needle, pen, or a pump. There is also an inhaled form of insulin called Afrezza.
Types of Insulin
There areseveral different types of exogenous insulin(insulin not made in the body itself, but that’s injected, pumped, or inhaled). They are different in how quickly they are absorbed, when they reach their peak effect, and how long they last in the body.
Usually insulin is prescribed as a regimen that includes a basal dose of intermediate or long-acting insulin with bolus dosing (a single dose given in a short period of time) of rapid-acting insulin given before meals.
Side Effects of Insulin
Side effects of insulin can result from the delivery of insulin, the effect of insulin on the body, and a possible allergy to the ingredients in the medication.
Side effects may include:
Effects of Insulin on Body
In the short term, insulin can cause seriously low blood sugar, orhypoglycemia. Symptoms can include:
Possible allergies to the other components in the drug can also cause seriousallergic reactionknown asanaphylaxis:
AnaphylaxisSeek immediate medical attention if you have symptoms of an allergic reaction to insulin as this can be life-threatening
Anaphylaxis
Seek immediate medical attention if you have symptoms of an allergic reaction to insulin as this can be life-threatening
Type 1 vs. Type 2 Diabetes: Different Insulin Effects
Prognosis
Before the discovery and development of insulin as a medication, diabetes had a much worse prognosis. With better understanding of the condition and with available treatment options, diabetes is a treatable chronic disease.
Studies demonstrate that people with diabetes have decreasedlife expectancycompared to those without diabetes.This is particularly true in those with poorly controlled blood sugar, kidney disease, and a younger age at diagnosis.
It’s especially important for people with diabetes to stop smoking and to control other health conditions like high blood pressure and high cholesterol to lower their risk of cardiovascular disease, which is a major cause of death in people with diabetes.
Complications
Chronically high levels of blood sugar are damaging to tissues andorgansin the body, which may lead to the following complications:
Summary
Insulin and blood sugar are both vital to the body. While blood sugar is an essential form of energy for the body, levels that are too high or too low are life-threatening. Insulin helps keep blood sugar in check. In people with type 2 diabetes, the relationship between insulin and blood sugar is dysfunctional, resulting in high blood sugar.
A diagnosis of type 2 diabetes can be daunting, particularly when treatment with insulin is needed. Learning how insulin works and how to administer it and keep your blood sugar levels in a safe range can take a lot of work and practice. Know that your healthcare team is available to answer questions and help get you on track to better blood sugar control and better health.
Frequently Asked QuestionsInsulin lowers blood sugar. Insulin is a hormone made in the pancreas that is secreted into the bloodstream after a meal. It helps cells in the body take up glucose so it can be used as energy or stored for later use.Insulin may eventually be required to treat high blood sugar as type 2 diabetes progresses. Insulin should be considered when hyperglycemia is severe (a hemoglobin A1c greater or equal to 10% or blood sugar greater than or equal to 300mg/dL), and in those who have unexpected weight loss. However, noninsulin medications such as GLP-1 drugs (like semaglutide or liraglutide) are preferred when possible.Learn MoreInsulin for Type 2 DiabetesWhile insulin is an essential hormone, not everyone with type 2 diabetes needs to be on insulin. A combination of exercise, dietary change, weight loss, and oral medications can avert the need for exogenous insulin (insulin that’s not made in the body but needs to come from other sources).For some people with type 2 diabetes, it’s possible with diet, exercise, and weight loss to lower blood sugar enough not require any blood sugar lowering medications. This is known as diabetes regression.Learn MoreCan You Reverse Type 2 Diabetes?
Frequently Asked Questions
Insulin lowers blood sugar. Insulin is a hormone made in the pancreas that is secreted into the bloodstream after a meal. It helps cells in the body take up glucose so it can be used as energy or stored for later use.
Insulin may eventually be required to treat high blood sugar as type 2 diabetes progresses. Insulin should be considered when hyperglycemia is severe (a hemoglobin A1c greater or equal to 10% or blood sugar greater than or equal to 300mg/dL), and in those who have unexpected weight loss. However, noninsulin medications such as GLP-1 drugs (like semaglutide or liraglutide) are preferred when possible.Learn MoreInsulin for Type 2 Diabetes
Insulin may eventually be required to treat high blood sugar as type 2 diabetes progresses. Insulin should be considered when hyperglycemia is severe (a hemoglobin A1c greater or equal to 10% or blood sugar greater than or equal to 300mg/dL), and in those who have unexpected weight loss. However, noninsulin medications such as GLP-1 drugs (like semaglutide or liraglutide) are preferred when possible.
Learn MoreInsulin for Type 2 Diabetes
While insulin is an essential hormone, not everyone with type 2 diabetes needs to be on insulin. A combination of exercise, dietary change, weight loss, and oral medications can avert the need for exogenous insulin (insulin that’s not made in the body but needs to come from other sources).For some people with type 2 diabetes, it’s possible with diet, exercise, and weight loss to lower blood sugar enough not require any blood sugar lowering medications. This is known as diabetes regression.Learn MoreCan You Reverse Type 2 Diabetes?
While insulin is an essential hormone, not everyone with type 2 diabetes needs to be on insulin. A combination of exercise, dietary change, weight loss, and oral medications can avert the need for exogenous insulin (insulin that’s not made in the body but needs to come from other sources).For some people with type 2 diabetes, it’s possible with diet, exercise, and weight loss to lower blood sugar enough not require any blood sugar lowering medications. This is known as diabetes regression.
Learn MoreCan You Reverse Type 2 Diabetes?
17 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.What is diabetes?
Kolb H, Kempf K, Röhling M,et al.Insulin: too much of a good thing is bad.BMC Med.2020;18(224). doi:10.1186/s12916-020-01688-6
Food and Drug Administration.100 years of insulin.
American Diabetes Association.Diagnosis.
American Diabetes Association.Hypoglycemia.
MedlinePlus.Diabetic hyperglycemic hyperosmolar syndrome.
National Institute of Diabetes and Digestive and Kidney Diseases.Insulin resistance and prediabetes.
MedlinePlus.Diabetes- insulin therapy.
American Diabetes Association.Insulin basics.
MedlinePlus.Human insulin injection.
American Academy of Allergy, Asthma & Immunology.Anaphylaxis.
Tancredi M, Rosengren A, Svensson AM, et al.Excess mortality among persons with type 2 diabetes.N Engl J Med. 2015;373(18):1720-1732. doi:10.1056/NEJMoa1504347
National Institute of Diabetes and Digestive and Kidney Diseases.What is diabetes?
American Diabetes Association Professional Practice Committee.9. Pharmacologic approaches to glycemic treatment:Standards of Care in Diabetes-2024.Diabetes Care. 2024;47(Suppl 1):S158-S178. doi:10.2337/dc24-S009
National Institute of Diabetes and Digestive and Kidney Disorders.Insulin, medicines, and other diabetes treatments.
Perreault L, Pan Q, Mather KJ, Watson KE, Hamman RF, Kahn SE.Effect of regression from prediabetes to normal glucose regulation on long-term reduction in diabetes risk: results from the diabetes prevention program outcomes study.The Lancet. 2012;379(9833):2243-2251. doi:10.1016/S0140-6736(12)60525-X
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.Cookies SettingsAccept All Cookies
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.
Cookies SettingsAccept All Cookies
