What Causes Insulin Resistance? Everything to Know

Medically Reviewed By Kelly Wood, MD
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Insulin is a hormone that helps to regulate your blood glucose levels. It allows cells to receive glucose from the bloodstream. When your body develops insulin resistance, it can no longer maintain a healthy glucose level. Your pancreas makes the hormone insulin, which allows the cells in your body to receive glucose from the food you consume. If your cells resist insulin, they cannot absorb the glucose. This resistance results in higher blood glucose levels.

High blood glucose levels can increase your risk of developing prediabetes and diabetes. You can take steps to help your body better respond to insulin.

Read on to find out more about insulin resistance. This guide includes information about causes and treatments. It also discusses the relationship between insulin resistance, prediabetes, and type 2 diabetes.

Sex and gender

Sex and gender exist on a spectrum. This article uses the terms “female” and/or “male” to refer to sex that was assigned at birth. 

Learn more about the difference between sex and gender here.

What causes insulin resistance?

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Medical professionals do not know exactly what causes insulin resistance.

However, certain risk factors make you more likely to develop insulin resistance. They include:

It is important to note that you do not need to be overweight for your body to resist insulin.

Some medications may also increase your risk of insulin resistance. These include:

  • glucocorticoids
  • antipsychotic drugs
  • HIV medication

Contact your doctor if you have concerns about any of the risk factors of insulin resistance.

What are the signs of insulin resistance?

You will not usually experience any signs or symptoms of insulin resistance.

However, some people may develop acanthosis nigricans, a condition where the skin on the armpit or neck darkens. Some people also develop skin tags in these places.

If you have high blood glucose levels, you may also:

  • feel thirstier than usual
  • need to urinate more
  • feel more tired
  • feel a tingling sensation on the bottom of your feet

Some people with prediabetes may experience changes in their eyes that may lead to a condition called retinopathy. Retinopathy mostly occurs in people with diabetes. Around one-third of people with diabetes have diabetic retinopathy.

Find out about the symptoms of type 2 diabetes.

Is insulin resistance the same as prediabetes?

Insulin resistance can lead to prediabetes. Prediabetes affects around 1 in 3 adults in the United States.

If your cells resist insulin and cannot absorb glucose, the glucose stays in your blood. This causes higher blood glucose levels.

You may have prediabetes if you have high blood glucose levels that do not meet the threshold for diabetes.

Prediabetes can also occur if your pancreas does not make enough insulin to help keep your blood glucose levels in the expected range.

What is the relationship between insulin resistance and type 2 diabetes?

Insulin resistance can cause prediabetes. In some cases, prediabetes can lead to type 2 diabetes.

Most people with type 2 diabetes previously had prediabetes. If you have prediabetes, you can take steps to restore your blood glucose levels to a healthier range. Reducing your blood glucose levels reduces your risk of developing type 2 diabetes.

The main ways of lowering your blood glucose levels include losing either 7% of your body weight or 10–15 pounds if you are 200 pounds. It is also important to exercise regularly.

Learn more about type 2 diabetes.

When should I contact a doctor?

Contact your doctor if you have concerns about insulin resistance. You will not usually have any symptoms of insulin resistance or prediabetes.

Your doctor can carry out tests to determine whether or not you have prediabetes or diabetes. They will also be able to advise on steps you can take to reduce the risks of either condition.

How is insulin resistance diagnosed?

A doctor will not usually carry out tests for insulin resistance. However, they can carry out tests to check for prediabetes.

Tests for prediabetes and diabetes can include:

  • fasting plasma glucose (FPG) test
  • A1C test
  • oral glucose tolerance test (OGTT)

Test results that indicate either prediabetes or diabetes can suggest that you are experiencing insulin resistance.

Fasting plasma glucose test

Before the FPG test, your doctor will ask you to fast for at least 8 hours. They will then usually test your FPG levels first thing in the morning.

  • A healthy FPG level is less than 100 milligrams per deciliter (mg/dL).
  • FPG levels of 100–125 mg/dL can suggest prediabetes.
  • FPG levels of 126 mg/dL or over can indicate diabetes.

A1C test

A1C measures your average blood glucose levels over the previous 3 months.

Unlike the FPG test, you do not need to fast for the A1C test.

  • A healthy A1C level is less than 5.7%.
  • An A1C level of 5.7–6.4% can suggest prediabetes.
  • An A1C level of 6.5% or over can indicate diabetes.

Oral glucose tolerance test

The OGTT takes around 2 hours to complete. Your doctor will check your blood glucose levels after you drink a special sweet drink.

The OGTT is more expensive and less common than other tests.

  • A healthy OGTT level is less than 140 mg/dL.
  • An OGTT level of 140–199 mg/dL can suggest prediabetes.
  • An OGTT level of 200 mg/dL or over can indicate diabetes.

How is insulin resistance treated?

If your doctor suspects that you have insulin resistance, they may recommend that you:

  • lose weight if you are overweight or have obesity
  • aim for a waist circumference of under 40 in if you are male or 35 in if you are female
  • get regular exercise

There is no medication approved to specifically treat insulin resistance. However, diabetes medication such as metformin and thiazolidinediones (TZDs) can increase your insulin sensitivity.

What is a good diet if I have insulin resistance?

There is no single diet that can help to reverse insulin resistance.

However, eating a balanced diet and getting regular exercise can help you achieve or maintain a healthy weight for you. This, in turn, can help increase your sensitivity to insulin.

Find out more about what to eat if you have insulin resistance.

How can I prevent insulin resistance?

You can take steps to reduce some of the risk factors of insulin resistance. These steps include:

  • maintaining a healthy weight for you
  • having a waistline below 40 in for males and below 35 in for females
  • getting enough physical exercise

Other frequently asked questions

Below are some more frequently asked questions about insulin resistance.

Does aspartame cause insulin resistance?

2020 study finds that artificial sweeteners directly impact people with type 2 diabetes. However, more research is necessary on whether the artificial sweetener aspartame directly causes insulin resistance.

Contact your doctor if you have concerns about artificial sweeteners in your diet.

Can you reverse insulin resistance?

If you experience insulin resistance, you can take steps to encourage your body to respond better to insulin. Exercising regularly, losing weight, and eating a balanced diet can help reverse insulin resistance.

Does insulin resistance make it more difficult to lose weight?

Insulin resistance can make it harder to lose weight as your body stores blood sugar as fat instead of converting it into energy. Eating a healthy, balanced diet and exercising regularly can help you lose weight. Your doctor will also be able to advise on steps you can take to make your weight loss journey more effective for you.

Find out more about when to consider professional help for weight loss.

Summary

Insulin resistance occurs when the cells in your body become less sensitive to insulin. This means that your body cannot convert blood glucose into energy. High blood glucose levels can lead to prediabetes and type 2 diabetes.

You may not experience any symptoms of insulin resistance. Risk factors for insulin resistance include having obesity and not getting enough exercise.

Contact your doctor if you have concerns about insulin resistance. They can carry out tests to check for prediabetes or diabetes. They will also advise on steps you can take to either reverse or reduce your risk of insulin resistance.

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Medical Reviewer: Kelly Wood, MD
Last Review Date: 2022 Jun 29
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Basu, R. (2018). Insulin resistance & prediabetes. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance
  2. Diagnosis. (n.d.). https://www.diabetes.org/diabetes/a1c/diagnosis
  3. Insulin resistance and diabetes. (2021). https://www.cdc.gov/diabetes/basics/insulin-resistance.html
  4. Insulin resistance. (2021). https://familydoctor.org/condition/insulin-resistance/
  5. Lee, R., et al. (2015). Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657234/
  6. Mathur, K., et al. (2022). Effect of artificial sweeteners on insulin resistance among type-2 diabetes mellitus patients. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7014832/
  7. Svendsen, C. (2021). How to lose weight if you're diabetic. https://www.allinahealth.org/healthysetgo/prevent/how-to-lose-weight-if-you-are-diabetic
  8. Understanding insulin resistance. (n.d.). https://www.diabetes.org/healthy-living/medication-treatments/insulin-resistance