Type 2 diabetes is a chronic disease in which your body is unable to maintain healthy blood glucose levels on its own. Blood glucose is a type of sugar in your blood. Type 2 diabetes usually progresses over time and can lead to many serious health problems. Type 2 diabetes can be treated with medication and healthy lifestyle changes such as exercise, weight loss, and a healthy diet. If caught early, type 2 diabetes may be reversed.

Learn more about type 2 diabetes, including how it affects the body, what causes it, and what to expect from living with type 2 diabetes.

How Does Type 2 Diabetes Affect the Body?

When you eat carbohydrates (found in grains, potatoes, fruits, vegetables, dairy, beans, and sweets), they are broken down into glucose. Glucose is a form of sugar the body uses for energy. Glucose enters the bloodstream, which transports it to all the cells in the body.

Insulin, a hormone produced by the pancreas, signals cells to absorb glucose from the bloodstream. This process helps regulate how much glucose remains in the blood, which determines blood glucose levels.

In the early stage of type 2 diabetes, your body’s cells become less sensitive to insulin. This stage is called insulin resistance. At first, the pancreas responds by making more insulin to overcome that initial resistance, leading to low blood sugar after eating and sugar cravings. Over time, the cells become more and more insulin resistant, and the pancreas can’t make enough insulin to keep up. Without enough insulin, cells can no longer take in glucose and begin to starve. Blood glucose levels increase, causing damage to nerves, blood vessels, and organs. The higher blood glucose levels are, and the longer they stay high, the more damage they do.

Symptoms of type 2 diabetes vary from person to person, but commonly include:

• Intense hunger and thirst
• Fatigue
• Frequent urination
• Blurry vision
• Irritability
• Slowed healing
• Numbness or tingling in the hands or feet
• Frequent yeast infections
• Unintended weight loss, usually in a short amount of time

What Is the Difference Between Diabetes Type 1 and Type 2?

“Diabetes” is often used to refer to both type 1 and type 2 diabetes, but they have important differences. Type 1 diabetes is an autoimmune disorder caused by an overactive immune system, and it usually starts in childhood. Type 1 diabetes occurs when the body doesn’t produce insulin because the immune system attacks the cells in the pancreas that make insulin. Type 1 diabetes can be confirmed through a blood test to identify the antibodies that attack the pancreatic cells. People with type 1 are dependent on insulin treatment and cannot live without it.

Type 2 diabetes, on the other hand, is when the body does make insulin, but cells stop responding because of insulin resistance. Type 2 diabetes is most common in adults, but it is becoming more common in children and teenagers too. Doctors diagnose type 2 diabetes by taking a blood sample and testing blood glucose levels.

What Causes Type 2 Diabetes?

Type 2 diabetes is caused by a combination of factors, including:

• Genetic predisposition
• Body weight
• Lifestyle habits such as diet, exercise, and cigarette use

Some people are more likely than others to develop type 2 diabetes based on the genes they inherited from their parents, and people with a family history of diabetes are more likely to have it. According to the American Diabetes Association, American Indians, Latinos, Asians, and African Americans also have a higher risk for developing type 2 diabetes. Age is another factor, as type 2 diabetes is most common in people 35 and older.

Having a body mass index (BMI) score in the overweight or obese range and not getting enough physical activity can also increase type 2 diabetes risk.

The History of Diabetes

As early as 1500 B.C.E., Egyptians wrote about a disease that caused a “great emptying of urine.” The term "diabetes," meaning "siphon," came from the Greeks, while Indian doctors called it "honey urine" due to ants being attracted to diabetic urine. Between 400 and 500 C.E., Indian physicians distinguished between what we now know as type 1 and type 2 diabetes. In the 11th century, "mellitus," Latin for "honey," was added to the name.

In 1869, a German scientist discovered the insulin-producing cells in the pancreas. Finally, in 1921, Canadian researchers confirmed that a lack of insulin causes diabetes and that insulin injections reverse its symptoms.

Diabetes Treatments Have Improved Over Time

Insulin became available in the U.S. in 1923. At that time, insulin was derived from animals. In the 1980s, recombinant DNA biotechnology made human-derived insulin available. Human-derived insulin products worked better, and new insulin products continue to improve in effectiveness. Better syringes, insulin pumps, and other insulin delivery methods have also continued to improve.

In the 1990s, new diabetes medications became available. These medications work in various ways to make cells more sensitive to insulin and lower blood glucose levels. Among the new drug classes were biguanides such as metformin, sulfonylureas like glyburide (DiaBeta) and glimepiride (Amaryl), and glitazones like pioglitazone (Actos) and rosiglitazone (Avandia).

In the 21st century, new medications have included glucagon-like peptide 1 receptor agonists such as exenatide (Byetta) and DPP-4 inhibitors like sitagliptin (Januvia) and saxagliptin (Onglyza).

The latest class of diabetes medications is sodium glucose cotransporter 2 (SGLT2) inhibitors, including canagliflozin (Invokana), dapagliflozin (Farxiga), and empagliflozin (Jardiance). Combination drugs containing medications from more than one class — such as pioglitazone and metformin (Actoplus Met), glyburide and metformin (Glucovance), and sitagliptin and metformin (Janumet) — are also available. There are now 11 categories of drugs approved for controlling blood glucose levels, with more on the way.

How Common Is Diabetes?

Type 2 is the most common form of diabetes. Almost 1 in 10 people in the U.S. have type 2 diabetes. Not everyone with diabetes has been diagnosed. It’s estimated that one-third of people with diabetes may not know they have it. Early warning signs of type 2 diabetes, such as fatigue or increased thirst and urination, are often mistaken as signs of aging or symptoms of other conditions.

What Is the Prognosis for Diabetes?

If you’re living with type 2 diabetes, it can be helpful to know what to expect and what you can do to improve your quality of life.

In 2024, according to the Centers for Disease Control and Prevention, diabetes is the eighth most common cause of death among people in the U.S. Diabetes — which increases the risk for heart disease and kidney disease — is commonly listed as an underlying cause or contributing factor of death on death certificates. A 2023 study suggested that people with diabetes live, on average, six years less than those without the condition.

People with type 2 diabetes have better outcomes and fewer complications when they follow healthy eating guidelines, exercise, and use medications and insulin as directed. Type 2 diabetes can’t yet be cured, but some people are able to reverse diabetes, or go into remission, by losing significant weight, exercising, and changing their diet. All of these changes decrease insulin resistance.

Health care providers consider diabetes reversed when a person is able to control blood glucose without medication over a long period of time. Reversal is more likely in the early stages of diabetes, when the pancreatic insulin-producing cells aren’t “fatigued” yet.

Quitting smoking is another important step. Although smoking itself won’t influence your blood sugar levels, people who smoke and have diabetes develop cardiovascular complications much sooner than people with diabetes who do not smoke. These complications include coronary artery disease, stroke, and peripheral arterial disease.

Is Type 2 Diabetes Very Serious?

Type 2 diabetes can lead to serious complications and even death. It’s difficult to consider whether you can die from type 2 diabetes, but it’s important to know the risks of uncontrolled diabetes and how your prognosis may improve with proper diabetes management.

Talk to your health care team about how to keep your diabetes under control and what you can do right away to not only help prevent serious complications of diabetes but also feel your best in your day-to-day life.

Regularly monitoring your blood glucose at home helps you better control your glucose levels and gives your doctor a clear picture of how well your medication is working. Follow your doctor’s instructions on when to test, and keep accurate records of each result.

Talk With Others Who Understand

On DiabetesTeam, the social network for people with type 2 diabetes and their loved ones, more than 159,000 members come together to ask questions, give advice, and share their stories with others who understand. Many members also live with fatty liver disease.

Do you have type 2 diabetes? What do you do to take good care of your health? Share your experience in the comments below, or start a conversation by posting on your Activities page.