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Type 2 diabetes is a chronic condition in which the body cannot use the hormone insulin effectively (called insulin resistance) and, over time, does not make enough insulin to keep up. Insulin moves sugar (glucose) from the bloodstream into cells for energy. When it doesn't work properly, glucose builds up in the blood, and persistently high levels can damage blood vessels, nerves, eyes, kidneys, and the heart.
Type 2 diabetes is by far the most common form of diabetes, accounting for roughly 90% to 95% of all diagnosed diabetes in the United States. About 40.1 million Americans—around 1 in 8 people—have diabetes, and more than 1 in 4 adults with diabetes don't know they have it. An additional 115.2 million U.S. adults (more than 2 in 5) have prediabetes, a state of higher-than-normal blood sugar that raises the risk of developing type 2 diabetes.
This article is for general education only and is not medical advice. Talk with a qualified clinician about your individual situation.
Type 2 diabetes develops from a combination of genetics, body weight, and lifestyle. Insulin resistance is closely linked with excess body fat (especially around the abdomen), physical inactivity, and aging.
Common risk factors include:
Having a risk factor does not mean you will develop diabetes—and many risks, such as weight and activity level, can be modified.
Symptoms often develop slowly over several years and can be mild or absent, which is why many cases go undetected. When symptoms appear, they may include:
Because early type 2 diabetes can be silent, screening matters even when you feel well.
Type 2 diabetes is diagnosed with blood tests, usually confirmed on a second test. Standard thresholds are:
| Test | Diabetes | Prediabetes | Normal | |---|---|---|---| | A1C | 6.5% or above | 5.7%–6.4% | Below 5.7% | | Fasting plasma glucose | 126 mg/dL or above | 100–125 mg/dL | 99 mg/dL or below | | Oral glucose tolerance test (2-hour) | 200 mg/dL or above | 140–199 mg/dL | 139 mg/dL or below | | Random plasma glucose (with symptoms) | 200 mg/dL or above | — | — |
The A1C test reflects average blood sugar over the past two to three months and does not require fasting. Your clinician decides which test to use and how often to screen.
Treatment of type 2 diabetes is individualized and aims to keep blood sugar, blood pressure, and cholesterol in healthy ranges while protecting the heart and kidneys. Most people use a combination of lifestyle measures and medication.
Lifestyle as foundation:
Medications (prescribed and monitored by a clinician):
Current guidelines emphasize selecting medication based on a person's cardiovascular and kidney risk and weight goals—not blood sugar alone. For carefully selected individuals, metabolic (bariatric) surgery may be an option with long-term medical support.
Daily management may include checking blood sugar as advised, taking medications as prescribed, attending eye and foot exams, monitoring blood pressure and cholesterol, not smoking, and getting recommended vaccinations. Diabetes self-management education and support programs improve outcomes.
See a healthcare professional if you have risk factors, are due for screening, or notice symptoms such as excessive thirst, frequent urination, fatigue, blurred vision, or unexplained weight loss.
Seek urgent care for very high blood sugar with symptoms like confusion, severe dehydration, rapid breathing, fruity-smelling breath, or vomiting—these can signal a medical emergency. If you take diabetes medication, also learn the signs of low blood sugar (shakiness, sweating, confusion) and how to treat it.
Several FDA-approved medication classes treat type 2 diabetes, and treatment is individualized by a clinician. Metformin (a biguanide) is a long-standing, low-cost first-line option. GLP-1 receptor agonists (for example, semaglutide/Ozempic and dulaglutide/Trulicity) and the dual GIP/GLP-1 agonist tirzepatide (Mounjaro) lower blood sugar, support weight loss, and several have proven cardiovascular benefit. SGLT2 inhibitors (for example, empagliflozin/Jardiance and dapagliflozin/Farxiga) lower glucose and have demonstrated heart-failure and kidney-protective benefits. Other approved classes include DPP-4 inhibitors, sulfonylureas, thiazolidinediones, and insulin. Current American Diabetes Association Standards of Care emphasize choosing therapy based on each person's cardiovascular and kidney risk, weight goals, and other health factors—not on glucose numbers alone. Only a licensed clinician can prescribe these medications; do not start, stop, or change any medication without medical guidance.
This page is for general information and is not medical advice. Always consult a qualified clinician about diagnosis and treatment. Individual results vary.