Understanding the Key Differences Between Type 1 and Type 2 Diabetes

Published March 15th, 2021 by Jacqueline Hensler, M.A.
Fact Checked by
Chris Riley
Medically Reviewed:
Camille Freking

Diabetes is a disease that affects how your body uses glucose, or sugar, to power the body with energy. A hormone called insulin acts as a guide to move glucose from food to your cells, where it’s used for energy.  

The two most common types of diabetes are type 1 and type 2. In type 1 diabetes, your body doesn't make any insulin. In type 2 diabetes, your body doesn’t make enough insulin, or it doesn’t use insulin efficiently. When this happens, glucose will remain in the bloodstream without being filtered out to cells leading to high blood sugar levels. The health consequences can be serious with complications that can lead to heart and kidney disease, vision loss, damaged nerves, and can affect organs and blood vessels. The life consequences can be just as serious as well, with medications that you are taking for your diabetes can even impact your options for life insurance with diabetes.

Diabetes is a chronic disease, and proper management of the condition may help avoid associated complications. If you support a loved one with the condition or if you have diabetes, understanding the key differences between type 1 and type 2 diabetes is important. The role insulin plays in your body, the primary causes and symptoms, and how to manage the condition are different between types 1 and 2. 

Learn more about what is the difference between type 1 and type 2 diabetes.   

What is the role of insulin in type 1 versus type 2 diabetes?

Insulin plays an important role in controlling blood glucose levels in the body. A key function of insulin is how it interacts with glucose to move it from the blood to cells. The role insulin plays is different for someone who has type 1 versus type 2 diabetes. 

When you have type 1 diabetes, your body doesn’t make insulin. Instead, your immune system destroys the cells that release insulin until you no longer produce it. By eliminating insulin production, your cells can’t receive glucose to control blood sugar levels.  

“Type 1 diabetes means that the patient has an absolute absence of insulin production,” explains Veronica Brady, PhD, RN, FNP-BC, BC-ADM, CDCES, and spokesperson for the Association of Diabetes Care and Education. “These people produce no insulin of their own, and they must always have insulin from an external source (injection or insulin pump).” 

With type 2 diabetes, your body does one of two things with insulin: it doesn’t make enough of it, or it doesn’t use it well. 

The difference in how insulin is used by the body means that a person with type 1 diabetes will need to take synthetic insulin daily. A person with type 2 diabetes may need to take insulin injections as well, but may also control blood sugar levels through eating healthy, exercising regularly, and taking recommended medications. 

How common is type 1 compared to type 2 diabetes?

Diabetes is a long-term health condition, and the number of people with it is on the rise. 

In 2018, 1.5 million adults in the United States were newly diagnosed with diabetes, according to a report by the Centers for Disease Control and Prevention (CDC). In the last 20 years, the number of adults with diabetes has doubled, the CDC says.

Type 1 diabetes primarily affects children, teens, and young adults. There is a genetic predisposition, so having a parent or sibling may increase your possibility of developing it too. 

The number of Americans with diabetes is 34.2 million people. Approximately 5% have type 1 diabetes, according to the Centers for Disease Control and Prevention (CDC). 

In comparison, 90-95% of individuals have type 2 diabetes, the most common form of diabetes, says the CDC. It’s a condition more common in adults over age 45, but is now also being seen in children. An unhealthy diet and physical inactivity are the major reasons behind developing type 2 diabetes. 

What are the symptoms for type 1 versus type 2 diabetes?

In both type 1 and 2 diabetes, the symptoms are similar. However, the way symptoms appear is very different. 

Common symptoms of type 1 and 2 diabetes include: 

  • Unintentional weight loss
  • Hunger  
  • Increased thirst 
  • Frequent urination 
  • Mood changes 
  • Irritability 
  • Blurred vision 
  • Wounds that heal slowly
  • Frequent infections

While symptoms may be the same between type 1 and type 2 diabetes, how long these symptoms take to appear happen in very different ways.  

Typically, symptoms of type 1 diabetes show up rapidly, often within a matter of weeks. 

“People with type 1 diabetes usually present with a sudden onset of symptoms like extreme fatigue and dry mouth, feelings of dehydration, and a significant increase in hunger,” Brady says. “Many times these patients will be seen in the emergency room for diabetic ketoacidosis (DKA).”

The symptoms of DKA can be quite serious and fatal if you experience this condition. 

Some early signs of DKA include: 

  • Nausea
  • Vomiting 
  • Abdominal pain 
  • Rapid breathing 
  • Shortness of breath 
  • Fruity-scented breath 
  • Confusion 
  • High blood sugar level 
  • High levels of ketones in urine 

Symptoms take much longer to appear in someone who has type 2 diabetes, often many years. Symptoms may be so mild that you may not notice them until health complications appear. 

“With type 2 diabetes, the symptoms are usually more subtle,” says Brady. “Patients notice changes over time. The reason for this difference is that with type 1 diabetes, the pancreas fails and with type 2 it is a progressive decline in beta cell function [pancreas function], but folks usually maintain some pancreatic function.” 

What causes type 1 diabetes and how is it different from type 2 diabetes?

The cause of type 1 diabetes is still unknown. Experts believe type 1 diabetes is the combination of a genetic predisposition from a parent or/and an environmental factor associated with a viral infection that activates the disease. 

If you have type 1 diabetes, you most likely have an autoimmune disease where the immune system does not function smoothly. In a person with type 1 diabetes, the immune system will attack the body’s healthy pancreas cells, and it will no longer produce insulin to regulate blood sugar. 

The cause of type 2 diabetes is different. Experts believe there are two factors at play. First, is insulin resistance, when your body doesn’t respond well to insulin. Second, is insulin deficiency, when your body doesn’t make enough insulin or process insulin well. 

Some risk factors for type 2 diabetes include weight gain, a poor diet, and lack of physical exercise. Carry extra weight raises your risk of diabetes, heart disease, and stroke, according to the American Diabetes Association (ADA). The ADA refers to it as: “Extra Weight, Extra Risk.”

Can you reverse diabetes?

A key difference between type 1 and type 2 diabetes is in managing the condition. 

You can not reverse type 1 diabetes. Since your body does not produce insulin, you are dependent on insulin injections. A healthy diet and an active lifestyle can help control the disease. 

“Decreasing the amount of carbohydrates and fats consumed can decrease insulin requirements, while exercise can help with lowering blood glucose numbers,” Brady says. 

Type 2 diabetes can be prevented and the condition can sometimes be reversed. With a healthy diet and exercise program, type 2 diabetes is manageable. 

“In light of the fact that type 2 diabetes is usually related to insulin resistance as a result of obesity, many times when patients lose weight their blood glucose levels will improve,” Brady says. 


Diabetes affects 34.2 million Americans, and the number continues to rise. There is no cure for diabetes. While type 1 diabetes can not be prevented, type 2 diabetes can. A healthy diet, regular exercise, and taking insulin or medications as needed can help both type 1 and type 2 diabetes. Understanding the key differences between type 1 and 2 diabetes is important for the long-term management of the disease.


CDC - 2020 overall cases and diabetes by the numbers and newly diagnosed numbers 

CDC - What is diabetes?

American Diabetes Association - Genetics of Diabetes 

World Health Organizations - Stats on Diabetes

NIH - Symptoms of diabetes 

NIH - Type 1 caused by viruses 

Mayo Clinic - DKA 

Kids Health - autoimmune disorders 


Veronica Brady, PhD, RN, FNP-BC, BC-ADM, CDCES, Assistant Professor, Clinical, Cizek School of Nursing, University of Texas 

ADCES Spokesperson - Association of Diabetes Care and Education

Board certified in advanced diabetes management

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