To understand the difference between type 1 diabetes and type 2 diabetes, it is important to understand how each condition impacts the body.   

We hope this resource will serve as a valuable guide to understanding the difference between type 1 and type 2 diabetes, and how someone could develop either condition. Always consult with a medical professional before deciding on any course of medical action.   

What is Diabetes?  

The medical name is diabetes mellitus (DM). Among the more commonly known types of diabetes are prediabetes, type 1 diabetes, type 2 diabetes, gestational diabetes, latent autoimmune diabetes in adults (LADA), and MODY (maturity onset diabetes of the young). Though there are many different types of diabetes, they all revolve around how the body does, or doesn’t, use or produce insulin. In this article we will focus primarily on type 1 and type 2 diabetes.   

When the body begins to break down food, it is converted into glucose (carbohydrates) — another name for sugar or blood sugar. When blood sugars start to rise, the pancreas is responsible for making and secreting a hormone called insulin. The role of insulin is to lower the blood sugar and let the body convert that sugar into energy.   

Jordan Pinsker, vice president and medical director at Tandem Diabetes Care, likens insulin to “the key that opens a locked door for the cells in your body. With insulin, that door can open, allowing glucose to enter cells and be used for energy.” 

Someone living with diabetes is either unable to produce insulin, or their body is resistant to insulin, and they cannot use it effectively.  

According to the Centers for Disease Control and Prevention, more than 34 million adults in the United States have some form of diabetes. Further, the number of cases of diabetes has doubled in the last 20 years.   

What are the Different Types of Diabetes?  

Type 1 diabetes: Type 1 diabetes (previously called juvenile diabetes, or insulin-dependent diabetes) is an autoimmune disease where the body attacks the cells that produce insulin. Insulin is the hormone that allows sugar (glucose) to be used as energy. Because the body cannot make insulin, a person has to inject insulin starting from when they are diagnosed.  

A common misconception of those who don’t understand diabetes is that lifestyle choices or diet choices can cause type 1 diabetes. There is no proven way to prevent the development of type 1 diabetes that exists today.  

Type 1 diabetes occurs when the immune system targets cells in the pancreas responsible for making insulin. Type 1 diabetes used to typically be diagnosed in childhood, but it has increasingly been diagnosed in adults as well. There is no cure for type 1 diabetes — just treatment, which requires daily management with insulin and careful checking of blood sugars.  

Type 2 diabetes: Type 2 diabetes is a condition resulting from how the body interacts with the hormone insulin. The major difference between type 1 and type 2 diabetes is that with type 2 diabetes, the body becomes resistant to insulin and is not able to effectively use the insulin that is produced. As blood sugars continue to rise, the body produces more and more insulin, but it does not work as well as it should. This creates what is called “insulin resistance.”   

Where type 1 diabetes is an autoimmune condition, where the body is attacking the cells of the pancreas, type 2 diabetes is a condition that develops over time for many reasons, more commonly in adulthood. It is important, however, to note that the occurrence of type 2 diabetes is on the rise in children and teenagers, according to the Centers for Disease Control and Prevention.   

There are steps people can take to reduce the chance of developing type 2 diabetes, or reducing its impact on their day-to-day management if they have already been diagnosed. The most important step a person can take is to live a healthy lifestyle by increasing exercise and following a healthy diet. However, many cases of type 2 diabetes can be linked to causes beyond lifestyle changes, such as age, genetic factors, medication use, and other medical conditions — not all of which can be changed or modified.  

Gestational diabetes: The American Diabetes Association estimates that nearly one in 10 pregnancies in the United States are impacted by gestational diabetes yearly. While it is unknown what specifically causes some women to develop gestational diabetes during pregnancy, the impact is that the mother is not able to keep up with the insulin needs of the body during pregnancy or use insulin effectively.   

It is important to note that when a woman develops gestational diabetes, she is at an increased risk for developing diabetes after the pregnancy. There are some studies, including one by the Canadian Medical Association Journal, that links gestational diabetes in the mother to an increased risk of diabetes in mother and child.   

Genetics, be it from the mother or father, can be a risk factor associated with the development of type 1 or type 2 diabetes. (See below for additional risk factors.) 

Prediabetes: Prediabetes occurs when someone has a blood sugar level averaging above a normal range. This could be a result of fasting (before breakfast), or high blood sugar readings after a meal — or both. This is considered a precursor to type 2 diabetes and is also known as insulin resistance. People with higher blood sugar levels should consult with their healthcare professional to see what steps or medications they can take to help maintain more normal glucose.   

What are the Symptoms of Type 1 and Type 2 Diabetes?

(Please note that the following symptoms may not be an indication of type 1 or type 2 diabetes for all individuals. Please consult a healthcare professional for further information.)  

These are some of the more common symptoms of type 1 or type 2 diabetes:  

• Frequent urination: This can occur because there is too much glucose in the blood and the kidneys are forced to flush it out through urine   
• Thirst: Like frequent urination, frequent thirst can be caused by an excess of high blood sugar  
• Nausea: An inconsistent metabolism from fluctuating glucose levels may lead to a feeling of nausea  
• Vomiting: Experiencing high or low blood sugar levels can lead to vomiting  
• Irritability: Mood swings can occur when there are changes in blood glucose  
• Atypical hunger: Excessive hunger can happen because the cells can’t convert blood sugar into energy  
• Unexpected weight loss: Even with an increased hunger and consumption, weight loss can still occur  
• Fatigue, sometimes extreme: With either form of diabetes, the body is unable to properly create energy, which can lead to fatigue  
• Blurred vision: Large amounts of glucose can cause swelling inside the eyes. This complication can last for several weeks or more.   
• Tingling or numbness in extremities (such as hands or feet, for example): This is typically a form of nerve damage that occurs over a long period of time because of high blood sugar levels  
• Recurrent infections: These could include, for example, yeast infections  

While the symptoms of type 1 diabetes and type 2 diabetes are similar, when they present can be very different. With type 1 diabetes, the symptoms are more likely to present quickly and are often more severe at the time of diagnosis. With type 2 diabetes, however, these symptoms can take much longer — sometimes years — to develop, and more often progress gradually.  

What are the Risk Factors for Type 1 and Type 2 Diabetes?  

The risk factors for type 1 diabetes are not as clear as they are for type 2 diabetes because, with type 1 diabetes, researchers don’t fully understand why the body’s immune system attacks the cells in the pancreas that are responsible for producing insulin. There are at least two that most medical professionals agree on. (Please note that the following risk factors may not be an indication of type 1 or type 2 diabetes for all individuals. Please consult a healthcare professional for further information.)   

Genetics/family history: Someone with a family member with type 1 diabetes is believed to be at an increased risk of developing type 1 diabetes. There is also a strong genetic component to type 2 diabetes.   

Age: While it is possible to develop type 1 diabetes at any age, it is more likely to occur in childhood, adolescence, or teenage years. However, many people are still diagnosed into adulthood. Type 2 diabetes can also be diagnosed in childhood, but this is far less common. There are increasing cases in adolescents, yet the majority of cases develop in adults.  

Some risk factors specific to type 2 diabetes include:  

• High blood pressure  
• A high-fat, carbohydrate-heavy diet  
• High cholesterol  
• Obesity  
• Ethnicity   
• Age  
• Family history  

  Note that there are some risk factors in women that may differ from those in men. However, the type 2 diabetes symptoms in men and type 2 diabetes symptoms in women are similar.    

  Women should be aware of the above risk factors, as well as:  

• Polycystic ovary syndrome (PCOS)  
• Gestational diabetes  

Diagnosing Type 1 and Type 2 Diabetes

The easiest way for a doctor to test for type 1 or type 2 diabetes is to have high blood sugar readings, along with signs and symptoms of diabetes. There are also some additional tests that measure glucose levels. These tests include:   

• Fasting Plasma Glucose (FPG)  
• Oral Glucose Tolerance Test (OGTT)  
• Random (or casual) Plasma Glucose Test  
• HbA1c (also called A1c)  
• Glucose in the urine  

According to Dr. Pinsker, who is also a leading pediatric endocrinologist, a physician may also test for antibodies that are associated with type 1 diabetes. This can help confirm a diagnosis of type 1 diabetes. While not everyone with type 1 diabetes has these antibodies, many people do.  

What are the Different Types of Insulin?

There are two primary types of insulin:  

Basal insulin: Sometimes referred to as “background insulin,” basal insulin mimics the way the body is constantly producing insulin for everyday activities. 

Bolus insulin: This is sometimes referred to as “mealtime insulin.” When someone consumes food, their blood sugars start to increase significantly, and someone who doesn’t make enough insulin will need an immediate boost of insulin to help regulate glucose levels. Bolus insulin is fast-acting and is ideally taken right before meals.   

Treating and Managing Type 1 Diabetes

Because there is no cure for type 1 diabetes, treatment and management require a lifelong commitment. Someone living with type 1 diabetes needs insulin. And while a diagnosis can be scary and intimidating, there are a wide range of resources available to assist with diabetes management, including always-evolving technologies and a supportive online community.  

There are several ways to deliver insulin into the body:  

Daily injections: A syringe with a needle is used to draw up and inject insulin. Treatment with multiple daily injections is also referred to as MDI therapy.

Insulin pens: Like a syringe, this delivery method is needle-based and requires multiple injections throughout the day. Pens can be convenient because the insulin is already in the pen, so all someone needs to do is dial up a dose to inject.  

Insulin pump: An insulin pump is a device that provides a steady release of insulin (called a basal rate), as well as allowing for bolus doses that can be given by the user. Pairing an insulin pump with a continuous glucose monitoring (CGM) device opens several options designed to make diabetes management easier, such as automated insulin dosing systems and advanced, predictive algorithms.  

Inhaled insulin: This powder-based, rapid-acting insulin is inhaled usually before meals and does not replace the need for basal insulin.    

While managing blood glucose levels through insulin therapy is the most important element of type 1 diabetes treatment, there are additional health factors to consider, such as regular exercise, following a healthy diet, and being able to properly count carbohydrate, fat, and protein intake. 

“Managing type 1 diabetes, especially at the time of diagnosis, can be overwhelming,” said Dr. Pinsker. “It is very important to recognize the need for a support system and ongoing resources for emotional and wellness support.”  

While there are several options for insulin therapy, Dr. Pinsker recommends, as a first step, to think about using a CGM sensor to monitor glucose levels.   

“The standard of care should be starting CGM as close to diagnosis as possible,” Pinsker said. “It’s a real game-changer. Once a person is using CGM, the next step is to look at more advanced forms of insulin delivery, such as an insulin pump that pairs with the CGM and can automate insulin delivery.”  

Treating and Managing Type 2 Diabetes

Like type 1 diabetes, the management of type 2 diabetes is dependent on regulating blood glucose levels. However, people living with type 2 diabetes may still be able to produce insulin for a period of time. Therefore, people with type 2 diabetes can often be treated with other medicines, such as pills and injections other than insulin, at least initially. Some individuals with type 2 diabetes will progress to require insulin treatment at some point.  

With proper management, type 2 diabetes can be more easily controlled. Many of these are non-medical treatments that depend more on lifestyle changes.   

Ways to help manage type 2 diabetes may include:  

• Regular exercise: Insulin resistance can actually decrease and insulin sensitivity can increase during exercise periods as the body looks to burn energy  
• Following a healthy diet: Eating healthy foods at regular times each day has been shown to help regulate blood sugar levels  
• Weight loss: Losing weight has been shown to improve insulin resistance and slow the continued onset of type 2 diabetes  
• Medication: In some instances, insulin therapy or additional medications may be required  

Additional lifestyle and diet changes may include:

• Shop as a family and teach children to read food labels  
• Substituting water for sugary drinks and sodas  
• Go for family walks   
• Limit screen time and promote more outdoor activities  
• Eat more fruits and vegetables  

  (Always consult with a medical professional before making any significant dietary changes or starting a new exercise regimen.)  

Who is Tandem Diabetes Care?  

Tandem Diabetes Care is dedicated to improving the lives of people with diabetes through relentless innovation and revolutionary customer experience. Tandem offers the t:slim X2™ insulin pump with advanced, predictive technologies that can anticipate blood glucose levels 30 minutes in advance and automatically adjust dosing when paired with a CGM sensor (sold separately).

Learn more about Control-IQ® technology, the easy choice to help protect from highs and lows with zero fingersticks.*   

Learn more about Basal-IQ® technology, which can help protect from lows.   

Talk to your healthcare professional to decide if the t:slim X2 insulin pump is right for you.   

Unless otherwise noted, all medical information was provided by Jordan Pinsker, MD, and Molly McElwee Malloy, RN, CDCES of Tandem Diabetes Care, Inc.    

*Zero fingersticks required when using the t:slim X2 pump with Dexcom G6 continuous glucose monitoring (CGM) integration. If glucose alerts and CGM readings do not match symptoms or expectations, use a blood glucose meter to make diabetes treatment decisions.

Responsible Use Control-IQ Technology

Even with advanced systems such as the t:slim X2 insulin pump with Control-IQ technology, you are still responsible for actively managing your diabetes. Control-IQ technology does not prevent all high and low blood glucose events. The system is designed to help reduce glucose variability, but it requires your accurate input of information, such as meals and periods of sleep or exercise. Control-IQ technology will not function as intended unless you use all system components, including your CGM, infusion sets and pump cartridges, as instructed. Importantly, the system cannot adjust your insulin dosing if the pump is not receiving CGM readings. Since there are situations and emergencies that the system may not be capable of identifying or addressing, always pay attention to your symptoms and treat according to your healthcare provider’s recommendations.

Important Safety Information

RX ONLY. The t:slim X2 insulin pump, Basal-IQ technology, and Control-IQ technology are intended for single patient use. The t:slim X2 pump, Basal-IQ technology, and Control-IQ technology are indicated for use with NovoLog or Humalog U-100 insulin. 

t:slim X2 insulin pump: The t:slim X2 insulin pump with interoperable technology is an alternate controller enabled (ACE) pump that is intended for the subcutaneous delivery of insulin, at set and variable rates, for the management of diabetes mellitus in people requiring insulin. The pump is able to reliably and securely communicate with compatible, digitally connected devices, including automated insulin dosing software, to receive, execute, and confirm commands from these devices. The pump is indicated for use in individuals six years of age and greater. Basal-IQ technology:Basal-IQ technology is intended for use with a compatible integrated continuous glucose monitor (iCGM, sold separately) and ACE pump to automatically suspend delivery of insulin based on iCGM readings and predicted glucose values. The bolus calculator is indicated for the management of diabetes by people with diabetes by calculating an insulin dose or carbohydrate intake based on user entered data. Basal-IQ technology is intended for the management of diabetes mellitus in persons six years of age and greater. Control-IQ technology: Control-IQ technology is intended for use with a compatible iCGM (sold separately) and ACE pump to automatically increase, decrease, and suspend delivery of basal insulin based on iCGM readings and predicted glucose values. It can also deliver correction boluses when the glucose value is predicted to exceed a predefined threshold. Control-IQ technology is intended for the management of Type 1 diabetes mellitus in persons six years of age and greater. 

Control-IQ technology and Basal-IQ technology are not indicated for use in pregnant women, people on dialysis, or critically ill patients. Do not use Control-IQ technology if using hydroxyurea. Users of the t:slim X2 pump, Basal-IQ technology, and Control-IQ technology must: be able and willing to use the insulin pump, CGM, and all other system components in accordance with their respective instructions for use; test blood glucose levels as recommended by their healthcare provider; demonstrate adequate carb-counting skills; maintain sufficient diabetes self-care skills; see healthcare provider(s) regularly; and have adequate vision and/or hearing to recognize all functions of the pump, including alerts, alarms, and reminders. The t:slim X2 pump, and the CGM transmitter and sensor must be removed before MRI, CT, or diathermy treatment. Visit tandemdiabetes.com/safetyinfo for additional important safety information. 

Control-IQ technology and Basal-IQ technology are not indicated for use in pregnant women, people on dialysis, or critically ill patients. Do not use Control-IQ technology if using hydroxyurea. Users of the t:slim X2 pump, Basal-IQ technology, and Control-IQ technology must: be able and willing to use the insulin pump, CGM, and all other system components in accordance with their respective instructions for use; test blood glucose levels as recommended by their healthcare provider; demonstrate adequate carb-counting skills; maintain sufficient diabetes self-care skills; see healthcare provider(s) regularly; and have adequate vision and/or hearing to recognize all functions of the pump, including alerts, alarms, and reminders. The t:slim X2 pump, and the CGM transmitter and sensor must be removed before MRI, CT, or diathermy treatment. Visit tandemdiabetes.com/safetyinfo for additional important safety information.