Key Takeaways
- Type 2 diabetes is a long-term condition in which blood sugar stays too high.
- About one in eight people in the United States has diabetes, mostly type 2.
- Excess weight is present in about nine in 10 people with type 2 diabetes.
- Nerve damage and poor blood flow can lead to foot ulcers and slow wound healing.
- Treatment includes healthy habits, weight loss when needed, and medicines that lower blood sugar.
Type 2 diabetes is a long-term condition in which your blood sugar stays too high. It is the most common type of diabetes.
Many people have type 2 diabetes for years without symptoms.
Over time, high blood sugar can damage the nerves and blood vessels in your feet and legs. This can make sores heal slowly.
What Is Type 2 Diabetes?
Type 2 diabetes is a condition in which your body does not use insulin well, so sugar builds up in your blood.
Insulin is a hormone made by your pancreas. It helps sugar from food move from your blood into your cells for energy.
In type 2 diabetes, your cells respond poorly to insulin. This is called insulin resistance. Your pancreas first makes extra insulin to keep up.
Over time, your pancreas cannot make enough insulin, and your blood sugar rises. Prediabetes is the earlier stage, when blood sugar is higher than normal but not yet diabetes. Prediabetes raises your risk of type 2 diabetes.
Diabetes, mostly type 2, is common in the United States:
- About 40.1 million people had diabetes in 2023, or about one in eight people.
- About 90% to 95% of diagnosed cases are type 2.
- More than one in four adults with diabetes do not know they have it.
- More than two in five adults have prediabetes. About eight in 10 of them do not know it.
How Is Type 2 Different From Type 1 Diabetes?
Type 2 diabetes differs from type 1 diabetes in how it starts and how it is treated.
Type 1 diabetes is thought to be caused by an immune reaction in which the body attacks itself by mistake. This reaction stops the body from making insulin. People with type 1 diabetes need insulin every day. Their symptoms can appear suddenly, in just a few weeks or months.
Type 2 diabetes develops over many years. It is usually diagnosed in adults, but more children, teens, and young adults now get it. Some people manage it with healthy eating and activity. Others need insulin or other diabetes medicines.
Gestational diabetes is diabetes that starts during pregnancy. It raises the later risk of type 2 diabetes.
What Causes Type 2 Diabetes?
The two main problems behind type 2 diabetes are insulin resistance and a pancreas that cannot make enough insulin.
Researchers do not fully know why these problems start. Several factors play a part:
- Excess weight (overweight or obesity) is present in about nine in 10 people with type 2 diabetes.
- Not being physically active.
- Genes and family history may contribute. Type 2 diabetes runs in families, but not in a simple pattern.
Who Is at Risk for Type 2 Diabetes?
Type 2 diabetes is more likely if you have excess weight, are not active, are older, or have a close family member with it.
Risk rises with age.
You may have a higher risk if you have any of the following:
- Overweight, obesity, or a waist of more than 40 inches in men or more than 35 inches in women who are not pregnant
- Physical activity less than three times a week
- A parent, brother, or sister with type 2 diabetes
- African American, Hispanic or Latino, American Indian, Alaska Native, Asian American ( even at a lower body weight), or Pacific Islander background
- Prediabetes
- A history of gestational diabetes, or having given birth to a baby who weighed 9 pounds or more
- Polycystic ovary syndrome, a hormone disorder
- High blood pressure
- Low HDL ("good") cholesterol or high triglycerides, a kind of blood fat
- A history of heart or blood vessel disease
- Fatty liver disease
- Smoking, including tobacco products and e-cigarettes
What Are the Symptoms of Type 2 Diabetes?
Type 2 diabetes symptoms often develop slowly over several years, and many people have none.
Some people learn they have diabetes only after a health problem appears, such as blurred vision or heart disease.
Here are some symptoms that may appear:
- More thirst than usual
- Urinating more often
- More hunger than usual
- Feeling very tired
- Blurred vision
- Numbness or tingling in your feet or hands
- Cuts, sores, or wounds that heal very slowly.
- Frequent infections, such as urinary tract, skin, or yeast infections.
- Weight loss without trying
- Feeling irritable
- Dark patches of skin around the neck, armpits, or groin
How Is Type 2 Diabetes Diagnosed?
Type 2 diabetes is diagnosed with blood tests that measure your blood sugar.
| Test | What It Measures | Prediabetes | Diabetes |
|---|---|---|---|
| Hemoglobin A1C test | Average blood sugar over the past two to three months | 5.7% to 6.4% | 6.5% or higher |
| Fasting blood sugar test | Blood sugar after no food for at least eight hours | 100 to 125 mg/dL | 126 mg/dL or higher |
| Two-hour glucose tolerance test | Blood sugar two hours after drinking a sugary drink | 140 to 199 mg/dL | 200 mg/dL or higher |
| Random blood sugar test | Blood sugar at any time of day | Not used | 200 mg/dL or higher with symptoms of high blood sugar |
These ranges apply to people who are not pregnant. Unless blood sugar is clearly very high, two abnormal results are needed to confirm diabetes.
Guidelines advise blood sugar testing on this schedule:
- For all adults, starting at age 35
- Earlier, at any age, if you have overweight or obesity plus another risk factor
- At least every three years if your results are normal
- Every year if you have prediabetes
- At least every one to three years if you had gestational diabetes
What Complications Can Type 2 Diabetes Cause?
Over time, type 2 diabetes can lead to nerve damage, poor blood flow, foot ulcers, slow wound healing, and heart, kidney, and eye problems.
High blood sugar can damage nerves and blood vessels throughout your body. Keeping your blood sugar close to your target can help prevent or delay these problems. Managing blood pressure and cholesterol can also lower the risk. Not smoking helps too.
Nerve Damage
Nerve damage is a common complication of diabetes that most often affects the feet and legs.
About half of people with diabetes have some kind of nerve damage. Peripheral nerve damage can affect the hands, feet, legs, and arms. It is the most common type. It usually starts in the feet.
Nerve damage can cause numbness, tingling, or pain. Up to half of people with peripheral nerve damage may have no symptoms. If you do not feel pain in your feet, you may not notice a cut, blister, or sore.
Your risk is higher if your blood sugar is hard to manage or you have had diabetes for a long time. Nerve damage in other parts of the body can affect the heart, stomach, bladder, and sexual function.
Poor Circulation
Poor circulation is low blood flow to the legs and feet, which diabetes can cause.
Not enough blood flow can make it hard for a sore or an infection to heal. Leg pain or cramping during activity is a reason to see your doctor right away.
Foot Ulcers and Amputation
A foot ulcer is an open sore or wound on the foot. Nerve damage and poor blood flow put you at risk of getting one.
Nerve damage is the most common cause of foot ulcers in people with diabetes. With diabetes, a foot ulcer can get infected and not heal well. If an infection does not get better with treatment, a toe, foot, or leg may need to be removed by surgery.
About 1.6 million people in the United States have a diabetic foot ulcer each year. About half or more of these ulcers become infected. Foot ulcers come before about four in five leg and foot amputations in people with diabetes. Diabetes is a leading cause of amputations not caused by injury in the United States.
Slow Wound Healing
Diabetes can make wounds heal slowly. A foot ulcer can take weeks or even months to heal.
Damage to nerves and blood vessels makes your feet more likely to get hurt. It also means an injury may not heal well. A bad infection that never heals can lead to gangrene (death of body tissue that can be serious or even fatal).
Good blood sugar control may help you heal and help your body fight infection. If you have a foot ulcer, keep it clean and bandaged as your care team instructs.
Heart, Kidney, and Eye Problems
Heart, kidney, and eye problems are serious long-term complications of type 2 diabetes.
People with diabetes are twice as likely to have heart disease or a stroke as people without diabetes.
About one in three adults with diabetes has chronic kidney disease. Diabetes is a leading cause of kidney failure.
Diabetes is also a leading cause of blindness in adults. It can damage the blood vessels in the retina of the eye, which is called diabetic retinopathy. Diabetes also raises the risk of clouding of the lens, called a cataract. It raises the risk of higher fluid pressure in the eye, called glaucoma.
Other Health Problems
Type 2 diabetes is also linked with these health problems:
- Gum disease and other dental problems
- Sexual and bladder problems
- Fatty liver disease
- Sleep apnea
- Depression
- Some types of cancer
- Dementia
Very high blood sugar can cause a dangerous condition that often starts during an illness. It needs hospital care right away. Some diabetes medicines can cause low blood sugar. The risk is higher with insulin and with sulfonylureas, a type of diabetes pill.
How Is Type 2 Diabetes Treated?
Type 2 diabetes is treated with healthy eating, regular activity, weight loss when needed, and medicines that lower blood sugar.
Managing your blood pressure and cholesterol is also part of treatment. So is quitting smoking if you smoke. Ask your doctor how often to check your blood sugar and what your target levels should be.
Some people, especially those who take insulin, use a continuous glucose monitor. This small sensor under the skin checks blood sugar every few minutes.
Because type 2 diabetes tends to get worse, you may need more than one medicine over time.
Healthy Habits and Weight Loss
Healthy habits and weight loss are a main part of treatment for type 2 diabetes.
A healthy eating plan and regular physical activity help lower blood sugar. If you have overweight, your eating plan may limit calories.
If you have overweight or obesity, losing 5% to 7% of your weight can improve blood sugar. For a 200-pound person, that's about 10–14 pounds.
Keeping off more than 10% of your weight usually brings greater benefit. For some people, it can lead to remission, which means blood sugar stays below the diabetes range without medicine.
Diabetes Medicines
Diabetes medicines can lower blood sugar when healthy habits are not enough.
Many people start with metformin. It helps your liver make less sugar. It also helps your body use insulin better.
Metformin may cause a small weight loss. Common side effects can include bloating, belly discomfort, and diarrhea. It is not used if kidney function is severely reduced. In rare cases, it can cause a serious buildup of lactic acid in the blood. Over time, it can also lower vitamin B12 levels, so your healthcare provider may recommend regular lab work to check.
Your doctor may choose or add other medicines if you have heart disease, heart failure, kidney disease, or excess weight. Talk with your prescriber before you start, stop, or change any medicine.
Other pills your doctor may discuss:
- SGLT2 inhibitors can cause weight loss and may help with heart failure and kidney disease.
- DPP-4 inhibitors usually do not change weight.
- Sulfonylureas can cause low blood sugar and weight gain.
- Thiazolidinediones can cause weight gain and fluid buildup. They can also cause or worsen heart failure, so they are not recommended for people with heart failure symptoms.
Insulin is one of the strongest medicines for lowering blood sugar. Some people with type 2 diabetes need it.
Tirzepatide and Other GLP-1 Medicines
Tirzepatide and other GLP-1 medicines are prescription medicines that lower blood sugar. They are used along with diet and exercise.
For type 2 diabetes, tirzepatide is sold as Mounjaro. It activates the body's targets for two natural hormones, GIP and GLP-1.
The FDA approved Mounjaro to improve blood sugar in adults and children 10 years and older with type 2 diabetes. It is also approved to lower the risk of heart attack, stroke, or death in high-risk adults with type 2 diabetes.
Tirzepatide and semaglutide are among the strongest medicines for lowering blood sugar. GLP-1 medicines may make you feel less hungry and help you lose some weight. They are not substitutes for insulin.
Each medicine below is also approved to lower the risk of heart attack, stroke, or death in some adults.
| Medicine | Brand For Type 2 Diabetes | How It Is Taken | Heart Benefit Approved For |
|---|---|---|---|
| Tirzepatide | Mounjaro | Shot under the skin once a week | Adults at high risk |
| Semaglutide | Ozempic | Shot under the skin once a week | Adults with heart or blood vessel disease |
| Semaglutide | Rybelsus and Ozempic tablets | Pill taken once a day | Adults at high risk |
| Dulaglutide | Trulicity | Shot under the skin once a week | Adults with heart or blood vessel disease or several risk factors |
| Liraglutide | Victoza | Shot under the skin once a day | Adults with heart or blood vessel disease |
Ozempic shots are also approved for adults with type 2 diabetes and kidney disease. In these adults, they can lower the risk of kidney disease getting worse, kidney failure, or death from heart or blood vessel disease.
Zepbound and Wegovy contain the same medicines as Mounjaro and Ozempic. They are not approved to treat type 2 diabetes.
Safety facts from the labels for these medicines include the following:
- Common side effects can include nausea, diarrhea, vomiting, constipation, belly pain, and decreased appetite.
- The risk of low blood sugar rises when you also take insulin or a sulfonylurea.
- The labels carry a boxed warning about thyroid tumors seen in rodents. It is not known if these medicines cause these tumors in people.
- The labels say not to use these medicines if you or a family member has had a type of thyroid cancer called medullary thyroid carcinoma. They also say not to use them if you have an endocrine system condition called Multiple Endocrine Neoplasia syndrome type 2.
- Serious side effects can include inflammation of the pancreas (pancreatitis), kidney injury from dehydration, gallbladder disease, and serious allergic reactions. Most of the labels also warn that diabetic eye disease (retinopathy) can get worse in people who already have it. Because these medicines slow stomach emptying, tell your care team before any surgery or procedure that uses anesthesia or deep sedation.
- These medicines require a prescription. Use them only as prescribed.
Weight-Loss Surgery
Weight-loss surgery is an option for some people with obesity and type 2 diabetes. It can greatly improve blood sugar.
It is also called bariatric or metabolic surgery. On average, it leads to a loss of more than 20% of body weight.
The surgery may bring blood sugar back to a healthy range. How long the improvement lasts can vary.
Can Type 2 Diabetes Go Into Remission?
Type 2 diabetes can go into remission for some people, but remission is not a cure.
Remission means your A1C is below 6.5% when measured at least three months after you stop all diabetes medicines.
Losing more weight and keeping it off raises the chance of remission. So does weight-loss surgery. Remission may not last, so regular checkups and blood sugar tests are still needed.
How Can You Protect Your Feet at Home?
You can protect your feet at home by checking them every day, so problems are found and treated early.Early treatment greatly lowers the risk of amputation.
If you care for someone with diabetes, help with these steps as needed:
- Check your feet every day for cuts, redness, swelling, sores, blisters, corns, or calluses. Use a mirror or ask a family member to check the bottoms of your feet.
- Wash your feet every day in warm, not hot, water. Do not soak them. Dry them completely.
- Never go barefoot, even indoors.
- Wear shoes that fit well and always wear socks with them. Check inside your shoes for pebbles or other objects.
- Trim your toenails straight across and smooth sharp edges with a nail file. Have a foot doctor trim them if you cannot see or reach your feet.
- Do not remove corns or calluses yourself. Do not use over-the-counter products to remove them.
Your care team should check your feet at every visit. You should also have a complete foot exam at least once a year. This exam checks the feeling and blood flow in your feet.
When Should You Call a Doctor?
Call your doctor or care team right away if you have any of these foot or leg warning signs:
- A cut, blister, or bruise on your foot that does not start to heal after a few days.
- Skin on your foot that becomes red, warm, or painful.
- A callus with dried blood inside it.
- A cut or sore on your foot that looks infected or will not heal.
- Tingling, burning, or pain in your feet.
- Loss of feeling, or trouble feeling heat or cold.
- A change in the shape, color, or temperature of your feet.
- Pain in your legs, or cramping in your buttocks, thighs, or calves, during physical activity.
Get emergency care right away if a foot infection turns black and smells bad. This can be a sign of gangrene.
If you have symptoms of diabetes or risk factors and have not been tested, ask your doctor about a blood sugar test.
Frequently Asked Questions
Is Type 2 Diabetes Genetic?
Type 2 diabetes is partly genetic, but it does not pass down in a simple pattern. Your risk rises with the number of close family members who have it. Families also share eating and exercise habits that affect risk.
Can a Healthy Person Get Type 2 Diabetes?
A person who seems healthy can still get type 2 diabetes. Age, family history, race or ethnic background, prediabetes, gestational diabetes, and inactivity can all raise risk. Still, excess weight is present in about nine in 10 people with type 2 diabetes.
What Happens If Type 2 Diabetes Is Left Untreated?
Type 2 diabetes that is left untreated can damage nerves, blood vessels, and organs over time. This can lead to heart disease, stroke, kidney disease, vision loss, foot ulcers, and slow wound healing. Very high blood sugar during an illness can also cause a dangerous condition that needs hospital care right away.
Does Type 2 Diabetes Shorten Life Expectancy?
Type 2 diabetes can shorten life expectancy, especially when it starts at a younger age. In a large study using older data from high-income countries, people diagnosed at 30 died about 14 years earlier on average than people without diabetes. These are group averages, not a forecast for any one person.
What Is It Like to Have Type 2 Diabetes?
Having type 2 diabetes often means daily self-care, even when you have no symptoms. You manage most of it yourself, with support from your care team and family. Daily care can include checking blood sugar, planning meals, staying active, and taking medicines as prescribed.
Can Type 2 Diabetes Be Prevented?
Type 2 diabetes can be prevented or delayed with lifestyle changes, especially if you have prediabetes. Losing about 5% to 7% of your weight and getting at least 150 minutes a week of brisk activity can lower your risk. For people with prediabetes, a structured lifestyle change program can cut the risk by more than half.
Sources
- Definition and How Common It Is: NIDDK Symptoms and Causes of Diabetes, 2024; NIDDK Type 2 Diabetes, 2017; CDC Type 2 Diabetes, 2024; CDC National Diabetes Statistics Report, 2026, data for 2023; CDC Diabetes Basics, 2026
- Causes and Risk Factors: NIDDK Symptoms and Causes of Diabetes, 2024; ADA Standards of Care, Section 9, 2026; MedlinePlus Genetics, Type 2 Diabetes; NIDDK Risk Factors for Type 2 Diabetes, 2022; CDC Diabetes Risk Factors, 2024; CDC Prediabetes, 2024; ADA Standards of Care, Section 2, 2026; CDC Put the Brakes on Diabetes Complications, 2024
- Symptoms: CDC Symptoms of Diabetes, 2024; NIDDK Type 2 Diabetes, 2017; NIDDK Symptoms and Causes of Diabetes, 2024
- Diagnosis and Testing: ADA Standards of Care, Section 2, 2026; CDC Diabetes Testing, 2024
- Complications: CDC Put the Brakes on Diabetes Complications, 2024; CDC Type 2 Diabetes, 2024; CDC Your Feet and Diabetes, 2024; CDC Nerve Damage, 2024; ADA Standards of Care, Section 12, 2026; NIDDK Diabetes and Foot Problems, 2017; Armstrong et al., JAMA, 2023; Harding et al., Diabetes Care, 2020; MedlinePlus Diabetes, Foot Ulcers, 2026; CDC Diabetes Basics, 2026; NIDDK Type 2 Diabetes, 2017; ADA Standards of Care, Section 6, 2026; ADA Standards of Care, Section 9, 2026
- Treatment: NIDDK Type 2 Diabetes, 2017; CDC Type 2 Diabetes, 2024; ADA Standards of Care, Section 6, 2026; NIDDK Insulin, Medicines, and Other Diabetes Treatments, 2022; ADA Standards of Care, Section 8, 2026; ADA Standards of Care, Section 9, 2026; Metformin label, 2026
- Tirzepatide and GLP-1 Medicines: Mounjaro label, 2026; Ozempic label, 2026; Rybelsus and Ozempic tablets label, 2026; Trulicity label, 2026; Victoza label, 2025; Zepbound label, 2026; Wegovy label, 2026; ADA Standards of Care, Section 9, 2026; NIDDK Insulin, Medicines, and Other Diabetes Treatments, 2022
- Weight-Loss Surgery and Remission: NIDDK Insulin, Medicines, and Other Diabetes Treatments, 2022; ADA Standards of Care, Section 8, 2026; Riddle et al., Diabetes Care, 2021; CDC Diabetes Basics, 2026
- Foot Care and Warning Signs: CDC Your Feet and Diabetes, 2024; NIDDK Diabetes and Foot Problems, 2017; CDC Nerve Damage, 2024; ADA Standards of Care, Section 12, 2026
- Genetics, Outlook, and Prevention: MedlinePlus Genetics, Type 2 Diabetes; Emerging Risk Factors Collaboration, Lancet Diabetes Endocrinol, 2023; CDC Type 2 Diabetes, 2024; CDC Prediabetes, 2024
This article is for general information only and is not medical advice.