What Is Insulin Resistance?

Insulin resistance is when your body's cells do not effectively use insulin, a hormone that regulates blood sugar (glucose) levels. As a result, your pancreas produces more insulin to help your cells get the energy they need and keep your blood glucose levels within a healthy range.

If insulin resistance worsens, your pancreas may have difficulty producing enough insulin, causing glucose to build up in your blood. High blood sugar levels can lead to prediabetes and eventually diabetes, causing increased thirst, fatigue, frequent urination, blurred vision, and dark patches of skin on your armpits, groin, or neck. 

About 40% of young adults in the United States have insulin resistance, and the prevalence increases with age. Genetic and lifestyle factors likely play a role in insulin resistance. Healthy lifestyle habits, including regular exercise and a balanced diet, can help reverse insulin resistance and prevent diabetes. 

Insulin Resistance Symptoms

If you have insulin resistance and your pancreas produces enough insulin to keep your blood sugar levels within the normal range, you likely won't have symptoms. Over time, insulin resistance can worsen, and your pancreas may not produce enough insulin to regulate your blood sugar effectively, leading to high blood sugar (hyperglycemia) and prediabetes. 

Signs and symptoms of elevated blood sugar levels and prediabetes include:

• Excessive thirst 
• Frequent urination
• Fatigue 
• Dry, dark patches of skin on your armpits, groin, or the back of your neck (acanthosis nigricans)
• Skin tags (small growths of skin) 
• Blurred vision
• Increased hunger
• Tingling on the bottom of your feet 

Causes

Researchers are still exploring what causes insulin resistance, but evidence suggests a combination of genetic and lifestyle factors play a role, including:

• Excess body weight and body fat: Excess weight is one of the leading causes of insulin resistance, particularly extra body fat around the waist and abdomen. A waist measurement of 35 inches or more for people assigned female at birth and 40 inches or more for people assigned male at birth can increase the risk of insulin resistance. Extra fat cells may cause inflammation or release hormones and other substances interfering with insulin sensitivity. 
• Inactive lifestyle: Lack of physical activity is linked to insulin resistance and other related conditions, such as obesity and type 2 diabetes. Research shows that even modest increases in physical activity, such as taking daily walks or engaging in low-impact exercise, can lower the risk of insulin resistance.
• High-carbohydrate diet: A diet high in carbohydrates and fats, particularly saturated fats, increases the risk of insulin resistance. Consuming excess carbohydrates and fats can lead to fat accumulation in the body, particularly in the liver and muscle tissue. This can interfere with the body's ability to use insulin properly.

Risk Factors

Certain risk factors can increase the likelihood of developing insulin resistance, including:

• Extra body weight or obesity 
• A family history of diabetes 
• Age 45 years or older 
• History of gestational diabetes 
• African-American, Latinx, Asian American, and Native/Indigenous ancestry 
• Smoking 
• Having certain health conditions, such as high blood pressure, high cholesterol, polycystic ovarian syndrome (PCOS), heart disease, and hormone disorders
• Sleep problems, such as sleep apnea 

Diagnosis

To diagnose insulin resistance, your healthcare provider will perform a physical exam, evaluate your symptoms and risk factors, and order lab tests. There is no specific test for diagnosing insulin resistance, so healthcare providers use blood tests to measure blood sugar (glucose) levels and insulin in your bloodstream. 

The following tests can help determine if you have or are at risk of prediabetes or type 2 diabetes:

• A1C test: Measures your blood sugar over the last 2 to 3 months. An A1C between 5.7 to 6.4% indicates prediabetes, and 6.5% or higher means you have diabetes. 
• Fasting blood glucose test: A blood sample is taken from your vein after fasting (not eating or drinking) for 8 hours or more. If your blood sugar level is between 100-125 mg/dL, it is a sign of prediabetes. Levels of 126 mg/dL or higher indicate diabetes. 
• Glucose tolerance test: Measures your blood sugar levels after consuming a glucose drink. You'll need to fast (not eat) for 8 hours or longer before the test. A fasting blood sample is taken, and then you'll drink the glucose-containing beverage. Your blood is drawn again one hour and two hours after. A blood glucose level of 140-199 mg/dL at the 2-hour mark indicates prediabetes and 200 mg/DL or higher indicates diabetes. 
• Insulin in blood test: Measures the amount of insulin in your blood after fasting for eight hours or more. If your insulin levels are higher than average, it can be a sign of insulin resistance or prediabetes. 

Treatments for Insulin Resistance  

Treating insulin resistance aims to improve your body's response to insulin and help keep your blood sugar levels within a healthy range. Treating insulin resistance can also help prevent or manage related health conditions, such as prediabetes, type 2 diabetes, and cardiovascular disease. 

Treatment for insulin resistance usually includes lifestyle habits and medications.

Lifestyle 

Healthy lifestyle choices can reverse insulin resistance and improve overall health and well-being. This may include:

• Balanced diet: Eating a healthy, nutrient-dense diet can help reduce insulin resistance. Eating whole grains, protein, fruits and non-starchy vegetables, and foods rich in fiber and low in carbohydrates is recommended. Research shows that eating more calories in the first half of the day and slow and mindful eating can also help reverse insulin resistance.
• Regular exercise: Regular physical activity can help improve your metabolism and your body's response to insulin. 
• Weight loss: If you have excess body weight, maintaining a healthy body weight is one of the best ways to reverse insulin resistance and lower your risk of diabetes. Talk to your healthcare provider about your weight loss goals; they can provide guidance on the healthiest way to lose weight.

Medication

There are no medications specifically for treating insulin resistance, but diabetes medications, such as metformin and thiazolidinediones (TZDs), can help improve insulin sensitivity and regulate blood sugar levels.

Prevention

Some risk factors for insulin resistance can't be changed, like your age and family medical history. But certain lifestyle modifications can help lower your risk of developing insulin resistance, such as:

• Maintain a healthy weight 
• Exercise regularly 
• Eat a healthy, balanced diet low in processed foods and high in fiber, fruits, and leafy green vegetables 
• Manage stress with relaxation techniques such as meditation, breathing exercises, and support from family and friends 
• Get regular health check-ups from your healthcare provider, including blood work to monitor your blood sugar levels 
  

Related Conditions 

Insulin resistance is closely linked to several other health conditions, including:

• Prediabetes and type 2 diabetes
• High blood pressure
• Abnormal cholesterol levels
• Cardiovascular disease, such as atherosclerosis (hardening and narrowing of the arteries) 
• Polycystic ovarian syndrome (PCOS), a hormonal disorder
• Obesity

Living With Insulin Resistance  

Insulin resistance requires ongoing management to prevent diabetes and maintain good health. Making healthy lifestyle choices and following your treatment plan can reverse insulin resistance and reduce your risk of developing related health conditions.

It may be challenging to change how you eat and increase your level of physical activity when you first begin. Lean on your support system, including your healthcare provider, family, and friends to help you stick with your healthy lifestyle, improve your health, and feel your best.