Insulin Resistance Explained: Symptoms, Causes, and Treatment
Insulin Resistance Explained: Symptoms, Causes, and Treatment
Insulin resistance happens when your body does not respond properly to insulin. This causes your blood sugar levels to rise over time. Your pancreas then tries to address this problem by secreting even more insulin.
This guide explains what insulin resistance is, who it affects, the symptoms to look out for, it's and the treatment options you can consider
If you are concerned about your blood sugar or metabolic health, visit our diabetes support page for further guidance.
Three key takeaways
Insulin resistance is common and often develops silently, but early identification can help you prevent it progressing to type 2 diabetes.
Lifestyle changes can improve your insulin sensitivity. This includes sustainable weight loss, balanced nutrition, and regular movement.
Testing and clinical guidance are important, as symptoms alone are not enough to confirm whether you have insulin resistance.
What is insulin?
Insulin is a hormone produced by your pancreas. It’s released when carbohydrates (including sugars like glucose) from foods like potatoes, bread, or biscuits enters your bloodstream.
Insulin helps send signals to your cells to let the sugar (glucose) from your blood in. This keeps your blood sugar levels at a safe level.
What is insulin resistance?
Insulin resistance isn’t the same as diabetes. It can affect people with and without diabetes at any age, but is more common during puberty, pregnancy, and menopause.
It often develops quietly but can increase your risk of type 2 diabetes, heart disease, and other metabolic conditions if left unmanaged.
Insulin sensitivity describes how effectively your cells respond to insulin. Higher sensitivity means your body uses insulin efficiently, keeping your blood sugar stable. Lower sensitivity is known as insulin resistance. And when resistance develops, the pancreas produces more insulin to compensate.
Trying to avoid insulin resistance is important, as higher sensitivity allows your body to efficiently use glucose for energy, preventing blood sugar buildup. This supports:
stable blood sugar levels
healthy metabolic functioning
lower long-term risk of type 2 diabetes developing
Who does insulin resistance affect?
Insulin resistance can affect anyone, but certain groups are at higher risk.
This includes:
people with higher body weight and BMI
people aged 40+ (or 25+ in some ethnic groups at higher risk, according to NHS guidance)
people with a family history of type 2 diabetes or genetic disorders
individuals with hormonal issues, like those affecting the thyroid
What causes insulin resistance?
Insulin resistance develops due to a mix of genetic, lifestyle, and hormonal factors. It's rarely caused by one single issue. Scientists are continuously researching what makes a person more susceptible to insulin resistance.
Common contributing factors include:
Genetics: certain inherited disorders like Muscular Dystrophy and Werner Syndrome.
Excess body fat: particularly around the abdomen and organs (visceral fat).
Low physical activity: movement makes your body more sensitive to insulin. It also builds muscle, which aids insulin absorption.
Diet: large consumption of foods that are highly processed and diets high in sugar.
What are the symptoms of insulin resistance?
Many people with insulin resistance have no obvious symptoms. It's often detected through blood tests rather than physical signs.
If caught early enough, you can manage certain aspects of your diet and lifestyle to reduce the likelihood of experiencing negative symptoms. However, if left untreated, the condition can worsen. Insulin resistance causes your pancreatic β‑cells to work harder and harder to produce more insulin. Over time, these cells become dysfunctional and unable to keep up with insulin demands. If this happens, symptoms can start to show.
When symptoms do occur, they may include:
fatigue and brain fog
increased hunger
difficulty losing weight
frequent urination and yeast infections
darkened skin patches (acanthosis nigricans)
skin tags
If you notice new or concerning symptoms, it's important to speak to a GP for assessment and testing.
Symptoms of insulin resistance in women
In women, insulin resistance is commonly linked to PCOS and hormonal changes. PCOS is associated with insulin resistance and can increase the risk of type 2 diabetes later in life.
Insulin resistance can contribute to weight gain, particularly around your abdomen. This is because higher insulin levels encourage the body to store fat, and may increase hunger.
Insulin plays a role in:
Fat storage: Instead of being used for energy, excess blood glucose is converted into body fat.
Regulating blood sugar: When cells ignore insulin, the pancreas produces more to compensate. High insulin levels promote fat storage and prevent fat breakdown.
Influencing appetite: High insulin levels can cause blood glucose ’crashes’, leading to intense hunger and cravings for high-carb, sugary foods.
When blood sugar rises and falls quickly, this can lead to increased hunger and cravings. This may make weight management feel more difficult, especially without structured lifestyle changes.
How to test for insulin resistance
There is no single universal test for insulin resistance, but several blood tests can indicate risk. This makes insulin resistance difficult to diagnose because there isn’t routine testing for it. A clinician will usually assess your overall metabolic profile:
Common tests include:
HbA1c (average blood sugar over 2–3 months, used to identify prediabetes and type 2 diabetes)
fasting blood glucose
oral glucose tolerance test
lipid profile
clinical assessment of weight, blood pressure, and family history
Your clinician will also look at several other factors beyond your metabolic profile when testing for insulin resistance. This includes:
your medical history
your family history
a general physical exam
logging increased signs and symptoms
How to tell if you have insulin resistance
Symptoms alone are not enough to diagnose whether or not you have insulin resistance. You’ll need to undergo blood tests and clinical assessment.
You should speak to a clinician if you:
have high risk factors, including family history or higher body weight
notice persistent fatigue or increased appetite and thirst
have PCOS
have a previous diagnosis for prediabetes
Early testing is important, as it can help prevent progression to type 2 diabetes.
What is severe insulin resistance?
Severe insulin resistance occurs when the body requires unusually high levels of insulin to control blood sugar. It's often linked to metabolic or hormonal conditions.
It may be associated with:
advanced metabolic syndrome
type 2 diabetes
rare genetic disorders
Management requires medical supervision and personalised treatment planning.
Insulin resistance and type 2 diabetes
Insulin resistance is a major driver of type 2 diabetes, as over time, the pancreas may struggle to keep up with increased insulin demand.
However, the progression from resistance to diabetes isn’t inevitable. Early lifestyle changes can significantly reduce this risk.
“Identifying insulin resistance early gives people an opportunity to make changes before blood sugar levels reach the diabetic range. Small, sustainable steps can have a meaningful long-term impact.”
Insulin resistance is common in people with PCOS and plays a role in hormone imbalance. It can worsen symptoms and increase long-term health risks.
Screening is important because PCOS increases the likelihood of developing type 2 diabetes. Insulin resistance can also affect fertility by disrupting ovulation.
Early management can improve both metabolic and reproductive health outcomes.
Can you reverse insulin resistance?
Insulin resistance can often be improved, especially in its early stages, but results vary. It's more accurate to describe it as manageable rather than fully reversible.
A balanced diet that supports stable blood sugar can improve insulin sensitivity. However, there’s no need to eliminate carbohydrates completely from your diet.
Focus on eating:
Low GI foods: Berries, no starchy vegetables, plant proteins.
Find out more with our guide to creating a diabetes diet.
What medications are used to treat insulin resistance?
Metformin is the most commonly prescribed medication to improve insulin sensitivity. It's often used to treat type 2 diabetes and sometimes PCOS.
GLP-1 receptor agonists, like semaglutide (the active ingredient in Wegovy), can also improve insulin sensitivity in people with type 2 diabetes or obesity. However, you’ll need a clinical assessment to determine whether this treatment is the right fit
These decisions will be made by a clinician based on your individual risk and medical history.
Insulin injections are not the first-line treatment for insulin resistance alone. They’re typically used in people with type 2 diabetes when other treatments haven’t worked.
Use of insulin to treat insulin resistance needs to be discussed with a clinician, and requires supervision and regular monitoring.
Does Mounjaro help with insulin resistance?
Mounjaro (tirzepatide) improves blood sugar control and can enhance insulin sensitivity in people with type 2 diabetes. It works by targeting hormones involved in glucose regulation.
It's prescribed under specific clinical criteria and isn’t suitable for everyone.
What are the possible complications of insulin resistance?
Untreated insulin resistance increases the risk of several serious health conditions.
These include:
type 2 diabetes
heart disease
fatty liver disease
stroke
metabolic syndrome
Seek urgent medical help if you experience any of the following symptoms:
chest pain
severe shortness of breath
sudden weakness or speech difficulty
symptoms of very high blood sugar, like confusion or extreme thirst
Frequently asked questions about insulin resistance
Can insulin resistance be temporary?
Yes. Insulin resistance can improve (and in some cases be reversed), particularly in the early stages. Lifestyle changes like regular exercise, weight management, improved sleep, and balanced nutrition can significantly improve insulin sensitivity.
Can you be a healthy weight and still have insulin resistance?
Yes. While excess weight is a common risk factor, insulin resistance can also affect people at a healthy weight. Genetics, hormonal conditions (like PCOS), chronic stress, and low physical activity levels can all contribute.
Does stress affect insulin resistance?
Yes. Chronic stress increases cortisol levels, which can raise blood glucose and reduce insulin sensitivity over time. Managing stress through sleep, exercise, and relaxation techniques may support better blood sugar control.
Is insulin resistance common?
Yes. Insulin resistance is very common and often develops gradually without obvious symptoms. It's closely linked to overweight and obesity, but it can also occur in people without these risk factors. Many people are unaware they have it until blood tests are carried out.
Are skin tags a warning sign of insulin resistance?
Skin tags and darkened skin patches (acanthosis nigricans) can be associated with insulin resistance. However, they are not diagnostic on their own and should be assessed by a healthcare professional.
Can fasting improve insulin resistance?
Some studies suggest that structured approaches like intermittent fasting may improve insulin sensitivity in certain people. However, fasting is not suitable for everyone and should be discussed with a clinician, particularly if you have diabetes or take medication that affects blood sugar.
Can exercise reduce insulin resistance?
Yes. Regular physical activity is one of the most effective ways to improve insulin sensitivity. Both aerobic exercise (like brisk walking or cycling) and resistance training help your muscles use glucose more efficiently.
Does insulin resistance always lead to type 2 diabetes?
No. Insulin resistance doesn’t automatically progress to type 2 diabetes. Early intervention through lifestyle changes can prevent or significantly delay this progression.
Can insulin resistance cause fatigue?
Yes. Insulin resistance can cause fatigue, particularly after meals. When cells struggle to absorb glucose properly, energy levels may fluctuate, leading to tiredness and brain fog.
How long does it take to improve insulin resistance?
This varies between individuals. Some people see measurable improvements in blood glucose levels within a few weeks of consistent lifestyle changes, while for others it may take several months.
What are the early symptoms of insulin resistance?
Early insulin resistance often has no obvious symptoms. When symptoms do occur, they may include fatigue, increased hunger, difficulty losing weight, darkened skin patches (acanthosis nigricans), and elevated blood sugar levels on blood tests.
What causes insulin resistance?
Insulin resistance is caused by a combination of genetic, hormonal, and lifestyle factors. Common causes include excess body fat (particularly around the abdomen), physical inactivity, chronic stress, poor sleep, certain medications, and conditions like PCOS.
How is insulin resistance diagnosed?
Insulin resistance is usually identified through blood tests. Doctors may check fasting glucose, HbA1c, fasting insulin levels, or calculate markers like HOMA-IR. It's often diagnosed before type 2 diabetes develops.
Can insulin resistance be reversed?
In many cases, insulin resistance can be significantly improved or reversed with sustained lifestyle changes. Weight loss (if appropriate), regular exercise, and dietary changes are the most effective strategies.
What foods help improve insulin resistance?
Foods that support insulin sensitivity include high-fibre vegetables, whole grains, lean protein, healthy fats (like olive oil and nuts), and minimally processed foods. Reducing refined carbohydrates and added sugars may also help stabilise blood sugar levels.
Is insulin resistance the same as prediabetes?
Not exactly. Insulin resistance often develops before prediabetes. Prediabetes is diagnosed when blood glucose levels are consistently higher than normal but not high enough to be classified as type 2 diabetes.
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