Updated March 13, 2026

Before developing type 2 diabetes, many people pass through a stage called prediabetes. Prediabetes means that blood glucose (sugar) levels are higher than normal but not yet high enough to meet the criteria for diabetes. Even at this stage, elevated blood sugar can begin to affect the body and increase the risk of future health problems.

In the United States, more than 2 in 5 adults have prediabetes, making it one of the most common metabolic conditions in the country. Many people are unaware they have it because the condition typically causes no symptoms.

Mihail Zilbermint, M.D., M.B.A., associate professor of clinical medicine at the Johns Hopkins University School of Medicine and a board-certified endocrinologist specializing in diabetes and metabolic disorders, explains what people should know about prediabetes and how it can be prevented.

What is prediabetes?

“Prediabetes occurs when blood glucose levels are higher than normal but not high enough to be classified as diabetes,” says Zilbermint.

When we eat, the body breaks down food into glucose, a form of sugar that circulates in the bloodstream and provides energy to cells. A hormone called insulin, produced by the pancreas, helps move glucose from the blood into the cells.

Prediabetes can develop when the body does not produce enough insulin or when the body’s cells become resistant to insulin, a condition known as insulin resistance. As a result, glucose builds up in the bloodstream.

Doctors may also refer to prediabetes as:

• Impaired fasting glucose (IFG)
• Impaired glucose tolerance (IGT)

Both terms describe early abnormalities in the way the body regulates blood sugar.

Prediabetes Symptoms

Most people with prediabetes do not experience symptoms. Because of this, many individuals are unaware they have the condition until it is detected through a blood test.

“In some cases, early nerve damage may already be present,” Zilbermint notes. “This can cause tingling or numbness in the hands or feet, although these symptoms are more commonly seen in people with diabetes.”

For individuals with risk factors, doctors often screen for prediabetes during routine medical checkups.

What causes prediabetes?

The exact cause of prediabetes is not always clear. However, several factors increase the likelihood of developing the condition.

“Body weight, diet and physical activity all play important roles,” Zilbermint explains. “Genetics can also contribute, since people with prediabetes often have close family members with type 2 diabetes.”

Risk Factors for Prediabetes

• Are over age 45 (though prediabetes can also occur in younger adults and children).
• Have a parent, brother or sister with type 2 diabetes.
• Are overweight or obese.
• Are physically inactive.
• Have a history of gestational diabetes.
• Have a history of Polyendocrine Metabolic Ovarian Syndrome (PMOS) .
• Belong to a population with higher diabetes risk, including African American, Hispanic/Latino, Asian, Pacific Islander or Native American.

Prediabetes Diagnosis

Doctors use several blood tests to diagnose prediabetes.

“For a diagnosis of diabetes, your health care provider will usually confirm the first test with a second test,” Zilbermint says.

A1C Test

This test measures the percentage of hemoglobin in the blood that has glucose attached to it. It reflects the average blood sugar level over the previous two to three months.

“The A1C test works a little like looking at how much sugar has built up on red blood cells over time,” explains Zilbermint. “Because these cells circulate in the body for about three months, the test provides a snapshot of average blood sugar levels during that period, rather than a single moment in time.”

• Normal: less than 5.7%
• Prediabetes: 5.7%–6.4%
• Diabetes: 6.5% or higher

Fasting Plasma Glucose Test

This test measures blood sugar after not eating for at least eight hours.

• Normal: less than 100 milligrams per deciliter (mg/dl)
• Prediabetes: 100 mg/dl–125 mg/dl
• Diabetes: 126 mg/dl or higher

Oral Glucose Tolerance Test

This test measures how your body reacts two hours after you have been given a special sugary drink.

• Normal: less than 140 mg/dl
• Prediabetes: 140 mg/dl–199 mg/dl
• Diabetes: 200 mg/dl or higher

Prediabetes Treatment

Healthy lifestyle

“A healthy lifestyle is the most effective way to reduce the risk of developing type 2 diabetes,” says Zilbermint.

Doctors usually recommend:

• Healthy eating patterns
• Regular physical activity
• Weight loss
• Participation in a diabetes prevention program

“Even modest weight loss can make a meaningful difference, ” says Zilbermint.

Medications: “For people at higher risk, medications such as metformin may help delay or prevent the progression to diabetes, ” says Zilbermint. “There are currently no long-term data supporting medications other than metformin specifically for preventing type 2 diabetes. However, newer medications such as GLP-1–based drugs can help with weight loss in people who are overweight or have obesity. Because weight management is a key part of preventing type 2 diabetes, these treatments may also play an important role in reducing diabetes risk.”

Self-care: Successfully managing prediabetes is possible when you can do the following:

• Eat a balanced, nutritious and healthy diet.
• Exercise regularly.
• Lose some weight. A relatively small amount of weight loss ― 5% to 10% of your body weight ― can help lower your blood sugar.
• Quit smoking.
• Manage stress and sleep.

If I have prediabetes, will I get diabetes?

Not necessarily.

Without lifestyle changes, many people with prediabetes will eventually develop type 2 diabetes. However, early intervention can significantly reduce this risk.

“Prediabetes is a warning sign, but it is also an opportunity,” says Zilbermint. “Even small lifestyle changes can improve blood sugar levels and help prevent the progression to diabetes.”

By taking action early, many people can delay or prevent diabetes and protect their long-term health.

Medically reviewed by Mihail Zilbermint, M.D., M.B.A.