Why do you not measure insulin or the HOMA index?

Because fasting insulin compares poorly between laboratories and no decision hangs on it in the Netherlands. The early traces are in values that are standardised and that you have measured anyway: fasting glucose, HbA1c, triglycerides and HDL, from one draw. The TyG index, calculated from fasting glucose and triglycerides, estimates insulin sensitivity from precisely those two numbers.

From which fasting glucose is it diabetes?

From 7.0 mmol/L, measured on two different days, and a doctor makes that diagnosis. Between 6.1 and 6.9 fasting glucose is called impaired: not yet diabetes, but the zone in which the body already works harder to keep sugar normal and in which losing weight, exercise and less sugar pay off most. Below 6.1 is healthy, and that is where lifestyle can take you back to.

Why do American HbA1c numbers differ from my report?

Different unit, same substance. American sources write HbA1c in percentages: 5.7 is called the start of prediabetes there and 6.5 diabetes. In the Netherlands it is in mmol/mol, where those same limits lie around 40 and 48, and diabetes is moreover established on glucose and not on HbA1c. Anyone who sets their report beside an American table compares units and not bodies.

Can you reverse insulin resistance?

Yes, and better than most blood values. Muscle mass and exercise raise sensitivity, weight loss around the belly lowers resistance, and fewer fast sugars and enough sleep do the rest. The values move along in order: the triglycerides within weeks, fasting glucose within months, and HbA1c looks three months back, so what you change only shows fully at the next measurement.

Insulin resistance

Insulin resistance means your body responds less well to insulin, the hormone that moves sugar from your blood into your cells. Your pancreas then makes extra insulin, and as long as that works your blood sugar stays normal. That is why you usually do not feel it. Your fasting glucose only shows later that something is wrong, together with your fats.

Medically reviewed by

Aäron Spapens

Lifestyle physician at Optimize

What are the symptoms of insulin resistance?

ComplaintEvidence
Dark patches in skin folds
A sign you see, not feel.
fair

How strong is the evidence?

strong: In the Dutch guideline, or confirmed in several controlled trials.
fair: From one controlled trial, an international guideline or a review of research.
limited: The research does not point one way.

Evidence as of October 2026. New research can shift this.

Insulin resistance itself you usually do not feel for years. Complaints such as thirst, frequent urination and blurred vision only belong with a blood sugar that is too high. Anyone who wants to know early therefore looks at their waist, their fats and their family, not at how they feel.

None of these complaints belongs to insulin resistance alone, and a measurement explains no complaint: the reading and the diagnosis belong with your GP. The complaint list follows the Dutch GP guideline on type 2 diabetes (NHG) and the American Diabetes Association.

Often named, not confirmed

You will run into these links everywhere. We list them deliberately, with what the research does show.

A slump after eating
Drowsiness after a big meal is normal; as a sign of insulin resistance it was never shown.
not confirmed

How does insulin resistance develop?

Insulin resistance develops in steps, often over years.

Your body responds less to insulinYour pancreas makes extra insulin. Your blood sugar stays normal, and you notice nothing.
Your fasting blood sugar risesThe extra insulin is no longer enough.Your fasting glucose
Type 2 diabetesYour blood sugar stays too high, also on average over months.Your HbA1c

When is your fasting glucose too high?

Creeps up through the years. Between 6.1 and 6.9 mmol/L it is called impaired.

Normal:

4.0 to 6.0 mmol/L

Your value

Enter your value as it appears on your results. Range for adults.

4.06.07.0

No value yet? How to get it measured

What do you do about insulin resistance?

Move briskly

Every day. Half an hour or more, so that you breathe faster. Your muscles then take up sugar.

Lose a little weight

If you are overweight. A few kilos less already makes a difference.

Fewer quick sugars

With every meal. Less soft drink, fruit juice and sweets. Drink mainly water, tea and coffee without sugar.

Have your blood sugar measured

Every 3 years. If you are over 45 and at higher risk. A blood sugar that is too high usually goes unnoticed.

The advice follows Thuisarts.nl, for a higher chance of type 2 diabetes.

What causes insulin resistance?

Lifestyle and weight

Belly fat is hormonally active and muscle is the largest consumer of glucose; both sides count.

Excess weight, especially around the belly
Little muscle activity and much sitting
Chronic short sleep

Predisposition

The same life does not give everyone the same resistance.

Type 2 diabetes in the family
A South Asian, Turkish, Moroccan or Surinamese background, where the risk starts earlier
Previous gestational diabetes

Hormonal and medication

Sometimes something else drives the resistance.

PCOS
Long-term corticosteroids such as prednisone

How to get insulin resistance measured

Every value below has its own page: what is normal, and what your value means.

Which blood values show insulin resistance?
Value	What it shows	Points here when
Fasting glucosedefining	Creeps up through the years. Between 6.1 and 6.9 mmol/L it is called impaired.	high

And 4 values that complete the picture

Which blood values show insulin resistance?
Value	What it shows	Points here when
HbA1c	The average of roughly three months. Moves slowly, and misses no single peak day because of it.	high
Triglycerides	Rises when the liver sees too much insulin. Often the earliest trace.	high
HDL Cholesterol	Falls in the same pattern. With triglycerides, the fat side of the story.	low
Triglycerides / HDL Ratio	The ratio of those two, and with that the most compact summary of this mechanism.	high

The comprehensive test (€229, single test) measures the values on this page.
Every draw is fasted: nothing to eat or drink from midnight, only water. Appointments are therefore in the morning, until 12:00.
You can draw at 600+ locations near you, no referral needed. See the locations
Results within 24 hours of analysis, in the app.

What is insulin resistance?

Insulin is the key that lets glucose into the cells. In insulin resistance that key turns ever more stiffly, and the pancreas solves that for years by simply making more insulin. Precisely that is why this stage is so invisible: glucose stays within the range while the machinery behind it runs at full speed. Complaints hardly belong with it; the first signals are in the values, not in how you feel. The traces can be read, though. Fasting glucose creeps up over the years, and between 6.1 and 6.9 mmol/L it is called impaired: not yet diabetes, but the antechamber. HbA1c summarises three months and moves slowly along. And often the fats are there first: rising triglycerides with a falling HDL is the classic trace of a liver that sees too much insulin, and a growing waist is the trace you see without a blood test. The cause is almost always a sum of belly fat, little muscle use, a lot of fast sugars and too little sleep, with disposition as an amplifier; in women PCOS belongs with it, and long-term prednisone or an underactive thyroid also lower sensitivity. Because the mechanism runs on lifestyle, it also runs back on it: working muscles take up glucose without insulin, and a smaller belly lets the liver listen again.

What is insulin resistance confused with?

Each with the one value that tells the two apart.

Type 2 diabetes

Distinguishing value: Fasting glucose

The line is agreed: a fasting glucose of 7.0 mmol/L or higher, on two separate days, and that diagnosis is made by a doctor. Everything before it is this page's terrain.

Underactive thyroid

Distinguishing value: TSH

Weight gain and low energy here too, but through a different hormone. TSH keeps the two apart.

Inherited high triglycerides

Distinguishing value: Triglycerides

Strongly raised triglycerides with tidy glucose values fits an inherited fat-metabolism variant sooner than insulin resistance. The whole pattern counts, not one value.

Frequently asked questions

They overlap, but they are different kinds of words. Insulin resistance is the mechanism: cells that listen less well to insulin. Prediabetes is a measurement label for the borderline zone, such as an impaired fasting glucose between 6.1 and 6.9 mmol/L or a raised HbA1c. You can have the mechanism for years before a measurement earns the label, and precisely in those years it is easiest to turn back with lifestyle.

Sources 4

1.NHG-Standaard Diabetes mellitus type 2. 2026. richtlijnen.nhg.org
2.American Diabetes Association, Standards of Care. 2026. diabetesjournals.org
3.WHO, Classification of diabetes mellitus. 2019. who.int
4.Thuisarts.nl (NHG), I have a higher chance of type 2 diabetes. 2026. thuisarts.nl

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This page explains what a result means. It is not a diagnosis and not treatment advice. Discuss complaints or an abnormal value with your doctor.

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