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Insulin Resistance – What You Need to Know

Written by Stephanie Booth, Alicia Racelis, PhD
Medically Reviewed by Melinda Ratini, MS, DO on July 14, 2026

Your body breaks down the food you eat to get glucose to use as its main source of fuel. After entering your bloodstream, insulin helps glucose get into your cells to be used or stored for later.

What is insulin resistance?

Insulin resistance happens when your muscle, liver, and fat cells don't respond well to insulin. Insulin comes from your pancreas; it helps manage your blood sugar, or glucose. Sometimes, insulin resistance is a short-term condition. But if left untreated for a long time, it could turn into diabetes.

Typically, lower glucose levels signal your pancreas to stop making insulin. If you have insulin resistance, this process doesn't work well, and your cells may not let glucose in when insulin "asks" them to. 

If left untreated, blood sugar levels can rise

Higher blood sugar can mean:

  • More and more blood glucose piles up in your bloodstream
  • Your pancreas keeps making extra insulin

For a while, this extra insulin might help your cells open up and let the glucose in, the way they're supposed to. This can keep your blood sugar within a normal range for a period. 

But over time, your cells may not respond as quickly, becoming more insulin resistant. Your blood glucose levels could keep rising.

Insulin resistance vs. diabetes

Insulin resistance and diabetes are related but not the same. If you have: 

  • Insulin resistance, your blood sugar is still normal.
  • Prediabetes usually points to some insulin resistance, with blood sugar levels higher than normal. But glucose levels still aren't high enough for diabetes.
  • Type 2 diabetescan happen if insulin resistance or prediabetes causes too much glucose to stay in your bloodstream. You'll need a plan to treat the higher than normal glucose levels.

What is insulin resistance syndrome?

If you inherit problems with the insulin gene or other health conditions that block how insulin works, you can get insulin resistance syndrome. It's rare, but you may:

  • Inherit changes in the insulin receptor genes that lead to type A insulin resistance syndrome
  • Have a rare autoimmune form of diabetes called type B insulin resistance syndrome

You can't tell that you have insulin resistance by how you feel. You'll need to get a blood test that checks your blood sugar levels. Seeing your doctor can help you know if you have insulin resistance.

Your doctor can run tests to check for signs of insulin resistance, including:

  • A waistline over 40 inches in men or over 35 inches in women
  • Blood pressure readings of 130/80 or higher
  • A fasting glucose level over 100 milligrams per deciliter (mg/dL)
  • A fasting triglyceride level over 150 mg/dL
  • An HDL ("good") cholesterol level under 40 mg/dL in men or 50 mg/dL in women
  • Skin tags
  • Patches of dark, velvety skin under your arms or on your neck (acanthosis nigricans)
  • Damage to tiny blood vessels in the backs of your eyes, which can lead to a condition called retinopathy

Experts still don't fully understand what causes insulin resistance and prediabetes. Things that can make this condition more likely include:

  • Extra weight, especially fat around the belly
  • Not being active
  • A diet high in carbohydrates, processed foods, and saturated fats
  • Medications such as steroids, some HIV treatments, and certain blood pressure medicines

The risk to develop insulin resistance may also be higher for some racial and ethnic backgrounds, including:

  • Asian Americans
  • Black Americans
  • Hispanics
  • Indigenous peoples
  • Latinos or Latinas
  • Pacific Islanders

Health conditions linked to insulin resistance

Certain health conditions can also increase your risk for insulin resistance. Let your doctor know if you have medical problems such as:

  • Metabolic dysfunction-associated steatotic liver disease (MASLD)
  • A family history of diabetes
  • A history of gestational diabetes
  • Genetic conditions such as myotonic dystrophy or inherited lipodystrophy
  • Sleep conditions such as sleep apnea

Some hormone problems are also linked to insulin resistance, such as:

  • Cushing's syndrome causes extra cortisol in your body, which can block how insulin works.
  • Hypothyroidism can slow your metabolism and cause insulin resistance.
  • Acromegaly can lead to high amounts of growth hormone, which can cause insulin resistance.
  • Polycystic ovary syndrome (PCOS)

Insulin resistance and PCOS

PCOS affects as many as 15% of people who are assigned female at birth (AFAB). It's one of the most common causes of infertility. With PCOS, your body has higher-than-usual amounts of hormones called androgens. 

These androgens can: 

  • Make it hard to get pregnant
  • Cause acne
  • Thin your hair

Most people with PCOS are also insulin resistant. The link between insulin resistance and PCOS is still unclear, but it's being studied. Your family history may play a part because you're more likely to have PCOS if:

  • Your mother or sister has PCOS
  • Your mother or sister has type 2 diabetes
  • You have excess weight

There isn't one specific test that checks for insulin resistance. To figure out if you have insulin resistance, your doctor will rely on a combination of tests.

 

Insulin resistance treatment aims to lower your blood sugar levels and prevent type 2 diabetes. This usually involves diet and exercise. 

Medication for insulin resistance

If diet and exercise aren't working for you, your doctor may suggest medication. Even though no medicine can cure insulin resistance, your doctor may prescribe drugs to treat other health issues:

  • Blood pressure meds to lower high blood pressure.
  • Metformin (Fortamet and Glumetza), if you're at higher risk of diabetes, to keep blood sugar levels in check.
  • Statins to treat high LDL ("bad") cholesterol.

Keep in mind that insulin resistance is a complex condition that doctors don't fully understand. In some cases, your blood sugar levels may not drop back to normal levels. But you may still be able to manage them.

If left untreated, insulin resistance could lead to:

Insulin resistance weight gain

In the short term, high blood sugar levels can cause you to gain weight. Losing those extra pounds can be a challenge because your body is using those fat cells to store extra glucose.

If your pancreas can't produce enough insulin to make up for your insulin resistance, your blood sugar levels could rise until you have prediabetes. 

Get screened

Screening for diabetes starts at age 35. But your doctor may screen you sooner if you have other risk factors for diabetes, including:

  • Extra weight
  • Gestational diabetes during a pregnancy, you'll get tested at least every three years

Testing for prediabetes

These blood tests can signal that you have prediabetes:

  • Fasting glucose test: 100-125 mg/dL
  • Oral glucose tolerance test: 140-199 mg/dL, after the second test
  • A1c: 5.7%-6.4%

If you do have prediabetes, you'll probably need to repeat these lab tests at least once a year so your doctor can keep an eye on your blood glucose levels. If your blood sugar levels continue to rise, you may get diagnosed with type 2 diabetes.

How to diagnose diabetes

Your doctor may confirm type 2 diabetes, if your test results show:

  • Fasting plasma glucose test: 126 mg/dL or higher
  • Oral glucose tolerance test: 200 mg/dL or higher after the second test
  • A1c: 6.5% or above

Can supplements help insulin resistance?

Unless you have a specific vitamin deficiency, the American Diabetes Association says there's no proven benefit from supplements. Make sure to talk to your doctor before trying any supplements, even if they're advertised as "safe" or "natural." They could still be harmful because of your health or the medications you take.

Insulin resistance and your diet

No specific diet is best to improve insulin resistance. But eating foods that are high in carbohydrates could make it worse. It's also a good idea to:

  • Limit highly processed foods — the ones where you don't recognize all the ingredients listed on the label.
  • Stay away from high-fat foods, which are calorie-dense.
  • Eat lots of high-fiber foods to help manage your blood sugar levels, as they keep you feeling full for longer.

Glycemic index and blood sugar

The glycemic index (GI) ranks foods based on how quickly they raise your blood glucose. High-GI foods are often high in carbohydrates and sugar but low on fiber. They quickly spike your blood sugar and insulin.

Low-GI foods, on the other hand, have a small, slow impact on your blood glucose. Try to choose these foods more often.

Some diet plans can help lower your risk of insulin resistance. Here are two diets that include higher fiber, lean proteins, and whole foods. 

 

Talk to your doctor about creating an eating plan that's right for you.

Insulin resistance doesn't mean you'll definitely get diabetes. But it's important to make changes to your eating habits and activity level, as healthy daily habits can protect your health. Getting your blood checked regularly will help your doctor keep an eye on your glucose levels.

Is a low-carb or keto diet required to reverse insulin resistance?

A specific diet isn't needed to reverse insulin resistance, especially those that may not work for everyone. Some studies say that weight loss is similar whether you're on the keto or Mediterranean diet.

Low-carb or keto diets may be popular methods to try and lower your blood sugar, but it's always best to speak with your doctor first. They can suggest a nutritionist to help create the best diet for your health.

How do chronic stress and high cortisol levels worsen insulin resistance?

Stress can cause higher amounts of a hormone called cortisol inside your body. The higher levels of cortisol can:

  • Lower your insulin sensitivity
  • Cause your cells to take in less glucose, leading to a buildup of glucose in your blood
  • Lead to higher blood sugar

My fasting blood sugar is normal. Is there a more sensitive test to catch insulin resistance earlier?

Doctors don't usually test for insulin resistance. Your fasting blood sugar is just a snapshot of glucose levels at that time. But your A1c tells your doctor about your blood sugar levels over the last few months. 

A1c can tell your doctor how hard it is for your body to manage your blood sugar levels over time. With insulin resistance, your body stops responding to insulin as it should, and your blood sugar starts to go which can mean a higher A1c percentage.

Can insulin resistance cause intense cravings, brain fog, and energy crashes after eating?

With insulin resistance, glucose might not get into your cells like normal, and it can affect how much energy your body has. Over time, your body may not get enough energy, and you may feel:

  • Sluggish with energy crashes
  • Hungrier than normal with cravings
  • Irritated or have brain fog

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