What Is Insulin Resistance?

This condition is a precursor to type 2 diabetes

Insulin resistance is when your body does not respond to insulin as it should. It is also known as impaired glucose tolerance.

Insulin helps your cells use the sugar glucose for energy. When your body is resistant to insulin, glucose can build up in your blood, causing high blood sugar.

Insulin resistance can progress to prediabetes and metabolic syndrome. If left untreated, long-term complications may develop, which include type 2 diabetes, heart disease, and vascular disease.

This article discusses some of the symptoms and causes of insulin resistance. It also looks at how this condition is diagnosed and treated.

prediabetes and metabolic syndrome

 Verywell / Ellen Lindner

Insulin Resistance Symptoms

Insulin resistance usually develops slowly and does not cause obvious symptoms. It can make you feel tired and low in energy, however. Since many people blame these effects on other factors such as lack of sleep, insulin resistance can go unnoticed for years.

When you have prediabetes or metabolic syndrome, chronically elevated blood sugar can cause noticeable symptoms. These may include:

  • Frequent urination
  • Excessive thirst
  • Dark, dry patches of skin on the groin, armpits, or back of the neck, known as acanthosis nigricans
  • Weight gain

You may experience some of these symptoms if you have insulin resistance. It is more likely, however, that you will not have any noticeable effects at all. If you do experience these symptoms, make sure to discuss them with your healthcare provider. They can be an important warning sign that you are at risk for diabetes.

Complications

Insulin resistance can cause a number of health problems over the long term. These include:

What Causes Insulin Resistance?

Insulin resistance is associated with a number of risk factors. The exact cause, however, is not completely clear. Some medical conditions may contribute to insulin resistance, including:

Risk Factors

Genetics, age, and certain lifestyle factors can also put you at greater risk of developing insulin resistance. These include:

  • Obesity
  • A sedentary lifestyle
  • Excess belly fat
  • Smoking
  • An age of 45 years or older
  • Having a first-degree relative with diabetes
  • African-American or Latinx ancestry

The relationship between insulin resistance and its risk factors is complicated because they can exacerbate and be exacerbated by one another.

Insulin and Blood Sugar

The pancreas releases insulin within a few minutes after eating. Normally, this hormone helps our bodies store glucose, a type of sugar used for energy. Insulin works by activating a protein on cells that binds to glucose. This allows the sugar to enter the liver, muscles, and fat cells.

With insulin resistance, the cells don't respond to insulin as they should. To compensate, the pancreas releases more insulin in an effort to stabilize blood glucose.

Lack of insulin or insulin resistance causes higher than normal levels of glucose in the blood.

Over time, this results in hyperinsulinemia, or too much insulin in the blood. Hyperinsulinemia does not effectively lower glucose. Instead, it makes it more difficult for the body to use stored energy.

Diagnosis of Insulin Resistance

To diagnose insulin resistance, your healthcare provider will start by conducting a physical examination. They will also consider:

  • Your medical history
  • Your overall health
  • Your risk factors

There is no diagnostic test that can verify insulin resistance or rule it out. Several tests can be helpful, however, if you have risk factors for insulin resistance. These include:

  • Fasting blood glucose test: A fasting blood glucose level between 100 milligrams per deciliter (mg/dl) and 125 mg/dl is typical with insulin resistance. If your fasting blood glucose reaches 100 mg/dl, you will be diagnosed with prediabetes. If it reaches 126 mg/dl, this means that you have diabetes. A fasting blood glucose test is routine at your yearly physical examination and may be done at other times if you have symptoms or risk factors for diabetes.
  • Oral glucose tolerance test: You will need to avoid eating and drinking for 12 hours before this test. You will have your blood sugar checked, drink a sugary fluid, and have your blood glucose tested again after a few hours. In general, blood glucose over 140 mg/dl after two hours is an indication of prediabetes. Blood glucose higher than 200 mg/dl points to diabetes. There may be a correlation between high blood glucose levels during an oral glucose tolerance test and insulin resistance.
  • Hemoglobin A1C test: This test measures your average glucose level over the previous two to three months. A normal level is between 4% and 5.6%. A level between 5.7% and 6.4% is consistent with prediabetes, and a level of 6.5% or above is typical of diabetes. Here, too, there is not a range that can diagnose insulin resistance, but elevated levels combined with risk factors and symptoms may suggest the condition.

Blood tests that measure your glucose levels can add to the overall clinical picture. They can't be used to confirm or rule out the diagnosis, however. There is also a chance that you may have insulin resistance but still have normal glucose levels.

Testing insulin levels is not a standard way to know if you have insulin resistance. It is one of the methods used in research studies, however.

Treatment

Insulin resistance and prediabetes are both highly predictive of diabetes. If you have been diagnosed with insulin resistance, you can take some action to prevent your condition from worsening.

Lifestyle

Lifestyle changes can reverse insulin resistance and help decrease your chances of developing diabetes, as well as improve your general health and wellness overall. Some of these changes include:

  • Exercise: Regular exercise helps raise the body's metabolism. This can prevent metabolic changes such as insulin resistance.
  • Diet: Most experts recommend the Mediterranean diet or the DASH diet as good ways to manage insulin resistance. Both diets emphasize healthy fats, fruits, vegetables, nuts, whole grains, and lean meat.
  • Weight loss: Maintaining a healthy weight is one of the ways to reduce the effects and progression of insulin resistance. Insulin resistance can contribute to weight gain, which can make weight loss more challenging. Talk to your healthcare provider if you need assistance developing and sticking to a weight loss program.

Belly fat is one of the biggest risk factors for insulin resistance. For this reason, losing excess abdominal weight is one of the best ways to help reduce your risk of developing prediabetes or diabetes.

Many of the lifestyle changes that can help manage insulin resistance can also help prevent it. It is never too late or too soon to make healthy changes to your diet and start an exercise program.

Medication

If you have insulin resistance, you may need treatment for related conditions such as hypertension, heart disease, or high cholesterol. Medications used to treat type 2 diabetes are sometimes prescribed for insulin resistance, but there is little evidence they can help control the condition.

Glucophage (metformin) makes the body more sensitive to insulin. It is used for the treatment of diabetes and often for prediabetic conditions such as insulin resistance.

Thiazolidinediones (also called glitazones), including Avandia (rosiglitazone) and Actos (pioglitazone), are medications that improve the body's response to insulin. They are prescribed for type 2 diabetes. Sometimes these medications are also used for the management of insulin resistance.

Keep in mind that all medications have side effects. For this reason, a diagnosis of insulin resistance does not necessarily mean you need to take prescription medication. You and your healthcare provider will need to weigh the pros and cons of this treatment option.

Natural Therapies

Because diet is so closely associated with insulin and glucose, many herbs and supplements have been considered as possible modifiers of insulin resistance. However, there is no evidence that supplements can control, reverse, or prevent the progression of insulin resistance.

Summary

Insulin resistance is when your body is resistant to the effects of the hormone insulin. This can lead to elevated blood sugar. Untreated, it can progress to prediabetes or type 2 diabetes.

You may be at higher risk of developing insulin resistance if you have conditions like high blood pressure or high cholesterol. Other factors like genetics, age, diet, and lifestyle can also play a role.

Treating insulin resistance often just means making healthy changes to what you eat and how often you exercise. Making these changes can decrease your risk of developing complications related to this condition.

A Word From Verywell

Insulin resistance is becoming more common among adults of all ages. It is considered a very early sign that you could be at risk for diabetes. Diabetes sets the stage for a number of serious health complications.

If you have insulin resistance, take it as a message from your body that it's time to take steps to improve your health. Addressing this condition early on can help protect you from its risks.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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