Insulin resistance and high insulin: what it means and what to do

With insulin resistance your cells respond less to insulin, and your pancreas makes more to keep your blood sugar normal. For years it causes no symptoms and your glucose stays normal: high insulin is often the first sign. The good news is that it often improves a lot with movement, sleep and diet.

What insulin resistance means

Insulin is the key that opens your cells to sugar. With insulin resistance your cells respond less, and your pancreas has to make more insulin to get the same effect.

For years this works: your glucose and HbA1c stay normal, but your fasting insulin is high. This is called compensated insulin resistance, and it is the best moment to act.

If your pancreas can no longer keep up, your glucose starts to rise: first prediabetes, then, in some people, type two diabetes.

What causes insulin resistance

There is often more than one at once.

• Belly fat: One of the most common causes. Fat around the organs makes your cells less sensitive to insulin.
• Too little movement: Your muscles use a lot of sugar. If they do little work, more insulin is needed for the same effect.
• Sugar and refined flour: Sugary drinks, sweets, white bread and pasta every day make your pancreas work harder.
• Too little sleep: Sleeping too little or badly is linked to more insulin resistance.
• Polycystic ovary syndrome: In polycystic ovary syndrome, insulin resistance is common, and it is part of the problem.
• Some medicines: Cortisone taken for a long time, for example. Tell your doctor, and do not stop it on your own.
• Family and age: The risk is higher if a parent, brother or sister has type two diabetes, and it grows with age.

Symptoms of insulin resistance

Usually none. It is often found by chance, on a blood test.

Sometimes there are signs worth noticing:

• A waistline that grows, even without many extra kilos
• Small soft skin tags on the neck or in the armpits
• Darker, velvety skin on the neck or in the armpits, called acanthosis nigricans
• In women, irregular periods, acne or extra hair, which can point to polycystic ovary syndrome

These signs can have other causes too. If you notice them, talk to your doctor: fasting insulin and glucose help find out. Tiredness and sleepiness after meals, on the other hand, happen to many people and mean little on their own.

Can insulin resistance be reversed?

It often improves a lot with the right habits, kept up over time. If they are not enough, your doctor considers medicines.

A large study showed this in people at risk of diabetes. Those who changed their diet, moved more and lost a little weight got diabetes far less often.

The first effects on blood tests usually show within a few months. That is why it is checked again after about three months.

Which tests to read alongside it

These tests show where you stand.

What your result means

The upper end of the fasting insulin scale, in µIU/mL.

• Within your report’s limits, Usually 2.6 to 24.9: Normal. Within your report’s limits. But insulin resistance can already be there, especially in the upper part. In the Rosa report you also see whether you are in your optimal range.
• Above your report’s limit, Usually above 24.9: High. Your pancreas is working hard to keep your glucose normal. Insulin resistance is usually behind it, sometimes a fast that was not kept. Check your glucose and HbA1c and talk to your doctor. If you had not fasted, repeat the test.

What to eat and how to move

You do not need a special diet: you need habits you can keep. Where to start:

• Move every day. Even a short walk after meals helps: your muscles use the sugar.
• Do strength training two or three times a week: more muscle means more sugar used.
• Less sugar and refined flour: sugary drinks, juices, sweets, snacks, white bread and pasta.
• What to eat: vegetables at every meal, legumes, whole grains, fish, whole fruit, nuts and olive oil.
• If you carry weight around your belly, losing even a few kilos helps a lot.
• Sleep enough, at regular times.

No supplement replaces these habits. If you already take medicines, do not change them on your own: talk to your doctor.

High insulin: when to worry

Talk to your doctor if:

• Your fasting glucose is 126 mg/dL or more, or your HbA1c is 6.5% or more: your doctor usually asks for a second test to confirm it.
• Your glucose or HbA1c rises from one test to the next.
• You have irregular periods, acne or extra hair: they can point to polycystic ovary syndrome.
• Your glucose is 200 mg/dL or more, or you are very thirsty, pass urine often and lose weight for no reason: see a doctor the same day.
• Your glucose is very high with vomiting, belly pain, fast breathing, confusion or severe drowsiness: call 112 or go to the emergency department.

With Rosa, a glucose of 126 mg/dL or more or an HbA1c of 6.5% or more is always flagged to a doctor; a glucose of 200 or more, urgently.

Frequently asked questions

Which tests show insulin resistance? Usually fasting insulin and glucose, which give the HOMA index, plus HbA1c and triglycerides. Sometimes your doctor also asks for a glucose tolerance test.

What is an insulin curve test? It is different from the fasting test: you drink a sugar solution, and glucose and insulin are measured several times over the next hours. Your doctor orders it if needed, and reads the results with you.

What is the right diet for insulin resistance? There is no single one. A simple pattern works: vegetables at every meal, legumes and whole grains, fish, whole fruit and olive oil, with little sugar and refined flour. A dietitian can help you turn it into a weekly menu.

Does insulin resistance make you gain weight? More often it is the other way round: belly fat is one of the most common causes of insulin resistance. Losing a little from your waist improves it, often with just a few kilos less.

Do you need medicines for insulin resistance? You usually start with habits. In some cases, for example with prediabetes or polycystic ovary syndrome, your doctor may consider a medicine such as metformin. Do not start or stop it on your own.

How often should it be checked again? If you are changing your habits, it is usually checked again after about three months, together with glucose and HbA1c. Rosa measures insulin once a year.

Sources

• Matthews and colleagues, homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations. Diabetologia, 1985. PMID 3899825
• Moriyama, a mini-review on insulin resistance assessment: the HOMA index and other surrogate indices, and their clinical use. World Journal of Clinical Cases, 2025. PMID 40933937
• Derakhshan and colleagues, high insulin and insulin resistance as risk factors for diabetes and prediabetes in adults with normal glucose, followed for about nine years. Diabetic Medicine, 2015. PMID 25131451
• Joham and colleagues, polycystic ovary syndrome. The Lancet Diabetes & Endocrinology, 2022. PMID 35934017
• Knowler and colleagues (Diabetes Prevention Program), fewer new cases of type two diabetes with lifestyle change or metformin. New England Journal of Medicine, 2002. PMID 11832527