Insulin resistance is a condition in which cells in your muscles, fat, and liver don’t respond well to insulin. Insulin is the hormone that moves glucose out of your blood. Your pancreas may make more insulin to compensate. Blood sugar can eventually rise, which increases the risk of prediabetes and type 2 diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Most people with insulin resistance feel fine. That is part of why it matters. The CDC reports that more than 2 in 5 U.S. adults have prediabetes, and about 8 in 10 of them don’t know it.
This guide explains how insulin resistance develops, what raises your risk, and how it’s detected. It also covers what you can do about it.
Key takeaways
- Insulin resistance usually causes no symptoms, and you can’t diagnose it from symptoms alone.
- Overweight and obesity are risk factors, but you don’t need either one to have insulin resistance.
- There is no routine test for it. Clinicians check blood glucose to find prediabetes and diabetes.
- Physical activity, balanced eating, and (when appropriate) weight loss can improve insulin sensitivity.
What Is Insulin Resistance?
Insulin resistance means your body doesn’t respond to insulin the way it should. It is not the same as diabetes. It is a change in how cells respond that can, over time, contribute to higher blood sugar.
What Does Insulin Do?
Insulin is a hormone made by your pancreas. The CDC describes the normal process this way:
- You eat, and your body breaks food down into sugars that enter your blood.
- The rise in blood sugar signals your pancreas to release insulin.
- Insulin acts like a key, letting sugar into your cells for energy.
- Your blood sugar returns to a normal level.
Insulin also tells your liver to store extra sugar for later. When you haven’t eaten for a while, your liver releases some of that stored sugar so your body always has fuel.
What Happens When the Body Becomes Insulin Resistant?
The CDC explains that when your body faces too much blood sugar over a long period, this system can get out of balance:
- A lot of sugar enters your bloodstream.
- Your pancreas releases high levels of insulin to move more of it into cells.
- Over time, your cells respond less well to insulin.
- Blood sugar stays high, so the pancreas keeps making more insulin.
- Eventually, the pancreas can’t keep up, and blood sugar rises.
When the liver and muscles are full of stored sugar, the liver sends the rest to be stored as body fat. The CDC notes this can lead to weight gain.
Researchers don’t fully understand every cause of insulin resistance. NIDDK notes that people with risk factors for type 2 diabetes are more likely to develop it.
What Causes Insulin Resistance?
Insulin resistance usually has several contributing factors rather than one cause. Some you can change, and some you can’t.
Excess Weight and Abdominal Fat
NIDDK lists overweight, obesity, and a large waist size as risk factors. But size alone doesn’t determine anything. The CDC states that you don’t need to have overweight or obesity to have insulin resistance, and you can’t tell by looking at someone.
Physical Inactivity
Not being physically active is a recognized risk factor. The CDC explains that regular activity makes your body more sensitive to insulin. It is one reason movement is so central to preventing and managing diabetes.
Genetics and Family History
A family history of diabetes raises your risk. So does a history of gestational diabetes (diabetes during pregnancy) or giving birth to a baby weighing 9 pounds or more, according to NIDDK.
Rates of prediabetes and type 2 diabetes are higher among several racial and ethnic groups in the U.S. The U.S. Preventive Services Task Force notes that these differences reflect social factors, not biology.
Age
Risk goes up with age, and NIDDK lists age 35 or older as a risk factor. Children and teens can also develop insulin resistance, so age is not a safeguard.
Certain Health Conditions
NIDDK links insulin resistance and prediabetes with several conditions:
- Polycystic ovary syndrome (PCOS)
- Sleep apnea
- Cushing’s syndrome and acromegaly (hormone disorders)
- Viral illnesses such as COVID-19
High blood pressure and unhealthy cholesterol or triglyceride levels often appear alongside insulin resistance. NIDDK also describes metabolic syndrome, a cluster of conditions that includes high blood pressure and a large waist size.
Medications and Hormonal Conditions
Taking certain medicines over time can contribute, according to NIDDK. Examples include glucocorticoids (steroids), some antipsychotics, and some HIV medicines. Never stop a prescribed medicine on your own. If you’re concerned, ask your prescriber about monitoring your blood sugar.
Smoking
NIDDK also lists smoking, including e-cigarettes and secondhand smoke, as a risk factor.
What Are the Signs of Insulin Resistance?
Insulin resistance itself often causes no obvious symptoms. Your body can compensate for a long time before blood sugar changes enough to notice.
Can You Have Insulin Resistance Without Symptoms?
Yes. NIDDK states that people with insulin resistance and prediabetes usually have no symptoms. The CDC likewise says type 2 diabetes symptoms often take several years to develop.
Possible Physical Clues
Some findings are associated with insulin resistance, but none confirms it:
- Acanthosis nigricans: dark, thick, velvety patches of skin, most often on the neck, armpits, or groin. A case report in Cureus describes it as most common in conditions such as obesity, metabolic syndrome, PCOS, and type 2 diabetes.
- A larger waist size, which NIDDK lists as a risk factor.
- Abnormal cholesterol, triglycerides, or blood pressure found during a checkup.
Acanthosis nigricans has other possible causes, including certain medications and, less often, malignancy. Research has also found no consensus on how well it estimates insulin resistance in individuals, such as a study of overweight adolescents. Have any new skin changes evaluated rather than assuming a cause.
Symptoms That May Indicate High Blood Sugar
These symptoms point to high blood sugar or diabetes rather than insulin resistance itself. The CDC and Mayo Clinic list them:
- Increased thirst
- Frequent urination
- Fatigue
- Blurry vision
- Losing weight without trying
These symptoms have many possible causes, so they are not proof of diabetes. If you have them, ask about blood testing. Our guides to diabetes symptoms and what causes fatigue can help you sort through possibilities.
Insulin Resistance vs. Prediabetes
The terms are related but not interchangeable. Prediabetes means blood glucose is higher than normal but not high enough for a type 2 diabetes diagnosis.
| Insulin resistance | Prediabetes | |
|---|---|---|
| What it is | Cells don’t respond normally to insulin | Blood glucose or A1C is above normal but below the diabetes range |
| How it’s identified | No routine clinical test | Blood tests (A1C, fasting glucose, or glucose tolerance test) |
| Symptoms | Usually none | Usually none |
| Relationship | Can contribute to rising blood sugar | Raises the risk of type 2 diabetes |
Does Insulin Resistance Cause Diabetes?
Insulin resistance is an important step toward type 2 diabetes, but it isn’t the whole story. The CDC says it “sets the stage” for prediabetes and type 2 diabetes. Type 2 diabetes also involves the pancreas gradually being unable to make enough insulin.
The general path looks like this:
Insulin resistance → higher insulin production → impaired glucose control → prediabetes → possible type 2 diabetes
Does Everyone With Insulin Resistance Develop Diabetes?
No. NIDDK states that not everyone with prediabetes develops type 2 diabetes, and steps you take can lower your risk. Your personal risk depends on many factors, including genetics, age, weight, and activity level.
For background, see our overviews of what diabetes is and type 2 diabetes.
Who Is at Higher Risk of Insulin Resistance?
Based on NIDDK and CDC lists, risk is higher if you have any of these:
- A family history of type 2 diabetes
- Overweight, obesity, or a large waist size
- Physical inactivity
- Age 35 or older
- A history of gestational diabetes
- PCOS, sleep apnea, or certain hormone conditions
- High triglycerides, high LDL cholesterol, or low HDL cholesterol
- Prediabetes or high blood sugar
- Long-term use of certain medicines
- Smoking
Having a risk factor doesn’t mean you have insulin resistance. It means testing and prevention deserve a closer look.
How Is Insulin Resistance Diagnosed?
There is no simple home test for insulin resistance. NIDDK explains that clinicians often don’t test for it directly, and the test for insulin resistance is primarily used in research.
Instead, your clinician checks how your body handles glucose. Blood testing equipment you can buy over the counter, such as a glucose meter, can’t diagnose diabetes.
A1C Test
The A1C test shows your average blood glucose over roughly the past 3 months. You don’t need to fast. NIDDK notes it can be unreliable with certain types of anemia or hemoglobin variants, so your clinician may use another test.
Fasting Plasma Glucose Test
This test measures your blood glucose at a single point in time, usually in the morning after fasting for at least 8 hours.
Oral Glucose Tolerance Test
For this test, you fast, give a blood sample, drink a sugary liquid, and give another sample 2 hours later. It is more expensive and harder to administer, so it’s used less often.
Here are the results ranges for nonpregnant adults, per NIDDK (source: American Diabetes Association):
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| A1C | Below 5.7% | 5.7%–6.4% | 6.5% or above |
| Fasting plasma glucose | 99 mg/dL or below | 100–125 mg/dL | 126 mg/dL or above |
| Oral glucose tolerance (2 hours) | 139 mg/dL or below | 140–199 mg/dL | 200 mg/dL or above |
Doctors usually confirm a diabetes diagnosis with a second test. Only a health care professional can interpret your results.
Other Metabolic Measurements
Your clinician may also consider blood pressure, waist size, and family and medical history. NIDDK says they may also recommend cholesterol and triglyceride tests, since these can shift with insulin resistance.
Can Insulin Resistance Be Improved?
For many people, yes. The CDC says you can reverse insulin resistance by making your cells more sensitive to insulin. Results differ from person to person, and improvement usually depends on sustained habits rather than a one-time fix.
Physical Activity
The CDC’s activity guidelines call for 150 minutes of moderate-intensity activity per week. That could be 30 minutes, 5 days a week, plus muscle-strengthening on at least 2 days. You can break it into shorter sessions.
If you’ve been inactive or have a chronic condition, talk with your clinician before starting. Our guide to the benefits of exercise covers ways to get started.
Healthy Eating Pattern
The CDC recommends a balanced diet with non-starchy vegetables, fruits, whole grains, and lean proteins. This helps lower blood sugar and, in turn, the amount of insulin your pancreas must release.
The 2025–2030 Dietary Guidelines for Americans call for cutting back on highly processed foods high in refined carbohydrates and added sugars. Practical steps include:
- Building meals around vegetables, fruits, and whole grains
- Choosing high-fiber foods and protein-rich foods you enjoy
- Watching portion sizes
- Limiting highly processed foods and added sugars
A Mediterranean-style eating pattern is one way to put this into practice. Our guides to a balanced diet and the healthiest foods to eat every day can help.
No single food or supplement fixes insulin resistance. You may see intermittent fasting promoted for it. If you take diabetes medicine, talk with your clinician before changing meal timing.
Weight Management
For people with overweight or obesity, modest weight loss can help. In the NIH-funded Diabetes Prevention Program, losing 5% to 7% of starting weight helped reduce diabetes risk in people at high risk.
Weight loss isn’t necessary or appropriate for everyone. If you’re unsure where you stand, see our weight management guide and ask your health care team.
Sleep and Stress Management
The CDC and NIDDK both include sleep and stress management in their lifestyle advice. Evidence for their direct effect on insulin sensitivity is less precise than for activity and weight. They still support overall health and make other changes easier. Try our tips on improving sleep and reducing stress.
Medications
Lifestyle changes are the foundation. Sometimes clinicians add medicine as well. NIDDK notes that metformin may be prescribed to help manage blood glucose and prevent type 2 diabetes. In the Diabetes Prevention Program it delayed diabetes and worked best for women with a history of gestational diabetes, younger adults, and people with obesity. Weight-loss medicines or surgery may help some people, and other medicines may treat related blood pressure or triglyceride problems.
These are prescription decisions, so don’t start or stop any medicine on your own.
Can You Prevent Insulin Resistance?
You can’t control every risk factor, such as age or genetics. You can influence several:
- Stay physically active most days.
- Follow a balanced eating pattern.
- Reach and maintain a healthy weight, if appropriate for you.
- Avoid tobacco and secondhand smoke.
- Get enough sleep and manage stress.
- Have blood pressure, cholesterol, and blood sugar checked as recommended.
The CDC says prediabetes and type 2 diabetes can be prevented with lifestyle changes. The CDC’s National Diabetes Prevention Program offers structured lifestyle programs. For everyday habits, see our guide to living a healthy lifestyle.
Insulin Resistance and Type 2 Diabetes Risk
Insulin resistance matters because of where it can lead. Persistently high blood sugar can strain your body over time.
NIDDK says type 2 diabetes can affect nearly every part of the body, including the heart, eyes, kidneys, and nerves. The CDC notes prediabetes raises the risk of type 2 diabetes, heart disease, and stroke.
The typical path is:
Insulin resistance → impaired glucose regulation → prediabetes → increased risk of type 2 diabetes
That path isn’t guaranteed. NIDDK reports that people with prediabetes have a high chance of developing type 2 diabetes within 5 to 10 years, but not everyone does. Your risk depends on your age, family history, weight, and health habits.
There is good news. The Diabetes Prevention Program Outcomes Study found that lifestyle changes or metformin could prevent or delay type 2 diabetes for at least 15 years. Finding elevated risk early gives you more time to act.
When Should You Get Tested for Diabetes or Prediabetes?
Ask a health care professional about testing if you have symptoms of high blood sugar or any of these:
- A family history of type 2 diabetes
- Overweight or obesity, especially with another risk factor
- Physical inactivity
- A history of gestational diabetes
- PCOS
- High blood pressure or abnormal cholesterol results
- Age 35 or older
The U.S. Preventive Services Task Force recommends screening adults aged 35 to 70 who have overweight or obesity. NIDDK adds that people with normal results are typically retested every 3 years. People with prediabetes should be tested for type 2 diabetes yearly. Testing is also recommended for children and teens aged 10 to 18 with overweight or obesity and another risk factor.
For a starting point, NIDDK links to the American Diabetes Association Diabetes Risk Test. It can’t diagnose anything, but it can help you decide whether to ask about testing.
Frequently Asked Questions
What is insulin resistance in simple terms?
Insulin resistance means your cells don’t respond to insulin as well as they should. Insulin normally helps glucose leave your blood and enter cells for energy. When cells respond poorly, the pancreas may release more insulin. Over time, blood sugar can rise, which may lead to prediabetes or type 2 diabetes.
What are the first signs of insulin resistance?
Often there are none. NIDDK notes that insulin resistance and prediabetes usually cause no symptoms. Some people develop dark, velvety skin patches (acanthosis nigricans) on the neck or in skin folds, but that isn’t a diagnosis. Blood tests show whether blood sugar is above normal.
Can you have insulin resistance without diabetes?
Yes. The pancreas can compensate for a while, so insulin resistance can exist before blood sugar reaches the prediabetes or diabetes range. Having it doesn’t mean you’ll develop diabetes, but it raises risk. Ask a clinician about your risk factors and whether screening makes sense.
Does insulin resistance always cause weight gain?
No. The CDC and NIDDK say insulin resistance can contribute to weight gain. But the CDC also notes that you don’t need overweight or obesity to have it. Body size alone can’t show whether someone has insulin resistance, so people at any weight may benefit from checking their risk factors.
Can insulin resistance be reversed?
Many people can improve insulin sensitivity. The CDC and NIDDK point to regular activity, balanced eating, weight loss if you have overweight or obesity, enough sleep, and stress management. Results vary, and ongoing habits matter, so work with your health care team on a plan that fits you.
What blood test shows insulin resistance?
No routine blood test diagnoses insulin resistance. NIDDK says the specific test is mainly used in research. Clinicians use A1C, fasting plasma glucose, or an oral glucose tolerance test to check for prediabetes or diabetes. They may also check cholesterol and triglycerides.
Is insulin resistance the same as prediabetes?
No. Insulin resistance describes how cells respond to insulin. Prediabetes is diagnosed when blood glucose or A1C results are higher than normal but below the diabetes range. Insulin resistance can contribute to prediabetes, but the two terms aren’t interchangeable, and you can have one without meeting the criteria for the other.
What foods should you avoid with insulin resistance?
No single food causes or cures insulin resistance. The Dietary Guidelines for Americans advise cutting back on highly processed foods high in refined carbohydrates and added sugars. The CDC recommends non-starchy vegetables, fruits, whole grains, and lean proteins. A registered dietitian can personalize advice, especially if you take diabetes medicine.
Does exercise help insulin resistance?
Yes. The CDC says physical activity makes you more sensitive to insulin. Adults should aim for 150 minutes of moderate activity weekly plus muscle-strengthening on 2 days. Shorter sessions count, and some activity beats none. Check with your clinician first if you have a chronic condition.
How does insulin resistance lead to type 2 diabetes?
When cells resist insulin, the pancreas releases more to compensate. Over time, it may not keep up, and blood glucose rises. Prediabetes can follow, and if levels keep climbing, type 2 diabetes can develop. This isn’t inevitable, and lifestyle changes can lower your risk.
Can insulin resistance go away?
It can improve, and in many people it does with sustained lifestyle changes. Age and genetics can’t be changed, so results vary. If a medicine or health condition contributes, your clinician can review your options. Regular blood sugar checks help track progress even after improvement.
When should I get tested for prediabetes?
Talk with a clinician if you have symptoms of high blood sugar or risk factors such as family history, overweight, prior gestational diabetes, or PCOS. The USPSTF recommends screening adults 35 to 70 with overweight or obesity. NIDDK says normal results are typically repeated every 3 years, and prediabetes calls for yearly testing.
Bottom Line
Insulin resistance is common, often silent, and closely tied to prediabetes and type 2 diabetes. You can’t diagnose it from symptoms or appearance, but you can act on your risk. Regular movement, balanced eating, and appropriate screening all help. If you have risk factors or symptoms of high blood sugar, ask your health care professional about testing.
This article is for educational purposes and isn’t a substitute for medical advice, diagnosis, or treatment. Always consult a qualified health care professional about your health.
Read our full Medical Disclaimer.
Sources
- NIDDK: Insulin Resistance & Prediabetes
- NIDDK: Diabetes Tests & Diagnosis
- CDC: About Insulin Resistance and Type 2 Diabetes
- CDC: Diabetes Basics
- CDC: Prediabetes Statistics
- CDC: Symptoms of Diabetes
- CDC: What Counts as Physical Activity for Adults
- CDC: National Diabetes Prevention Program
- USPSTF: Prediabetes and Type 2 Diabetes Screening
- Dietary Guidelines for Americans, 2025–2030
- Mayo Clinic: Diabetes Symptoms
- Cureus case report on acanthosis nigricans (PMC)
- Acanthosis nigricans and insulin resistance in overweight adolescents (PMC)
- EADV: Insulin resistance in acanthosis nigricans
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