Insulin resistance is a reduced response to this hormone in muscle, liver and fat tissue, often without specific symptoms. To find out where you stand, testing mainly looks for abnormal blood glucose: in France, a fasting level of 1.10–1.25 g/L falls within the prediabetes range, while 1.26 g/L or higher on two occasions allows diabetes to be diagnosed.
These figures concern venous blood glucose measured in a laboratory, not a threshold for insulin resistance. Normal blood glucose can coexist with compensation through increased insulin production.
What is insulin resistance?
Insulin is produced by the pancreas. It helps muscle and fat tissue use or store glucose and reduces glucose production by the liver. When these tissues respond less well, the pancreas can increase insulin secretion to maintain blood glucose levels.
This compensation can work for a while. If it becomes insufficient, glucose rises in the blood. This NIDDK definition explains why insulin resistance does not automatically mean diabetes.
Distinguish between the terms before interpreting a test result:
| Term | What it describes | What it does not prove |
|---|---|---|
| Insulin resistance | Reduced tissue response to the hormone | That symptoms or diabetes must be present |
| Hyperinsulinaemia | Elevated insulin in a given context | A single cause or a standalone diagnosis |
| Prediabetes | Abnormal blood glucose below diabetes thresholds | A direct measure of insulin sensitivity |
| Diabetes | High blood glucose meeting diagnostic criteria | A cause exclusively related to insulin resistance |
Our article on hyperinsulinaemia and its tests explores insulin secretion in more detail. Here, the aim is to understand the assessment and the decisions it supports.
How can you tell if you have insulin resistance?
You cannot confirm it with a checklist of how you feel. A useful approach combines medical history, clinical examination and tests selected by your doctor. The NIDDK notes that direct tests for insulin resistance are mainly used in research.
Prepare the information that genuinely helps guide the consultation:
- family history of type 2 diabetes
- overweight, obesity or an increasing waist circumference
- previous gestational diabetes or polycystic ovary syndrome
- high blood pressure, abnormal lipid levels or metabolic liver disease
- usual physical activity and medications taken
These risk factors listed by the NIDDK help determine whether screening is needed. None is sufficient alone, and a normal weight does not rule out risk.
A good question to ask is: “Which results would change my care?” It avoids ordering a shopping basket of biomarkers when nobody has planned what to do with the results.
Which symptoms or signs deserve attention?
Insulin resistance and prediabetes are usually silent. Fatigue after a meal, cravings, drowsiness or difficulty losing weight are too non-specific to establish this diagnosis. Counting them does not turn them into a validated test.
One skin sign particularly warrants examination: acanthosis nigricans, darker, thickened, velvety skin in folds, especially around the neck or armpits. The NCBI clinical review describes its association with insulin resistance, but also other causes. A photograph is not enough to identify the condition.
If your main problem is an energy slump, record its timing, duration and circumstances for a week. Bring these observations to your doctor if the symptom persists. Fatigue calls for an assessment of its causes, not an automatic hormonal label.
Insulin resistance testing: which blood tests should you ask for?
In French clinical practice, the priority is often fasting venous blood glucose. In its 2025 care pathway, HAS recommends diagnosing type 2 diabetes using venous blood glucose in someone at risk or with symptoms.
Here are the tests and their roles:
| Test | Information obtained | Role and limitations |
|---|---|---|
| Fasting venous blood glucose | Glucose concentration at the time of sampling | Priority for diagnosis in France; follow the laboratory’s fasting instructions |
| HbA1c | Glucose exposure over recent months | Useful depending on the context; does not directly measure insulin resistance |
| OGTT with 75 g of glucose | Blood glucose response after an oral glucose load | Requested in certain situations; more demanding |
| Lipid profile, blood pressure, waist circumference | Associated cardiometabolic risk | Guides prevention; does not confirm insulin resistance alone |
| Fasting insulin and HOMA-IR | Indirect estimate based on insulin and glucose | Additional tests, with no universal threshold to interpret in isolation |
| Hyperinsulinaemic-euglycaemic clamp | Insulin sensitivity under controlled conditions | Complex reference method, mainly used in research |
HbA1c can be misleading in certain medical situations. Your doctor selects tests and confirmation procedures according to the context, rather than applying every test to every reader.
Blood glucose: what are the thresholds in France?
The Assurance Maladie reference ranges for fasting venous blood glucose are as follows:
| Fasting blood glucose | General interpretation |
|---|---|
| Below 1.10 g/L | No impaired fasting glucose according to this reference range, without ruling out all insulin resistance |
| 1.10–1.25 g/L | French prediabetes range |
| At least 1.26 g/L | Diabetes threshold, requiring confirmation on two occasions depending on the context |
With suggestive symptoms, venous blood glucose of at least 2 g/L, measured at any time, also meets a criterion for diabetes. This warrants medical care.
These values do not apply to pregnancy-specific screening. Do not apply the American fasting threshold of 1.00 g/L as a French threshold without specifying the reference framework.
Is HOMA-IR a reliable test?
HOMA-IR combines fasting glucose and insulin to produce an indirect index. The review by Muniyappa and colleagues distinguishes these indices from direct measurements such as the clamp. A correlation in a study does not make an individual score infallible.
Results depend in particular on insulin assays and the population context. There is no single threshold applicable to all laboratories and all profiles. A result above a number found online is therefore not a prescription.
Before drawing conclusions, check with the prescribing clinician:
- sampling conditions and units
- the reference interval used by the laboratory
- consistency with blood glucose and clinical context
- the action planned if the result is confirmed
For the formula and its limitations, see the HOMA-IR guide · FR. An isolated score should not trigger extreme dietary restriction.
Insulin resistance: what practical steps can you take?
The first lever is your lifestyle, adapted to your health. Muscle uses glucose when it works, and regular activity helps improve metabolic balance. HAS recommends reducing sedentary time, being physically active and developing a personalised diet without excessive restriction.
The Diabetes Prevention Program, a randomised trial involving 3,234 high-risk participants, targeted 7% weight loss and 150 minutes of activity per week. Around three years later, diabetes incidence was reduced by 58% in relative terms, with approximately 5% versus 11% of participants developing diabetes per year.
This is a diabetes prevention result in a selected population receiving intensive support. It does not mean “58% less insulin resistance” and does not guarantee normalisation for every reader.
A four-week starter plan
This practical framework helps organise habits, without claiming to replicate the DPP:
- Week 1: take stock. Prepare your medical history, medications and test results, then arrange a consultation if indicated.
- Move regularly. Start with a daily walk suited to your fitness level, then build towards 150 minutes of moderate activity per week.
- Add strength training. Physical activity recommendations for adults include at least two sessions per week.
- Reorganise your meals. Replace sugary drinks with an unsweetened option and keep your food varied, including vegetables, pulses and protein sources.
- Reassess after four weeks. Look at consistency, tolerance and progress. Follow-up blood tests follow your doctor’s schedule, not your watch’s.
The Assurance Maladie activity guidelines are targets to adapt, not an obligation to start at full intensity immediately.
Can it be corrected without medication?
Lifestyle changes can improve metabolic risk, but some situations also require treatment. Metformin or other medications should be discussed according to the diagnosis, coexisting conditions and medical goals. Do not start or stop treatment based on a HOMA-IR result.
Prolonged fasting, completely eliminating carbohydrates and “anti-insulin” supplements are no substitute for this approach. Marketing loves to cast a hormone as the enemy. Your body still needs it.
When should you seek prompt or emergency care?
Unusual thirst, frequent urination, blurred vision or unexplained weight loss require a prompt medical consultation. Vomiting, abdominal pain, abnormal breathing, severe dehydration or confusion can accompany a metabolic emergency: call 15 or 112.
Pregnancy, known diabetes or medication that can cause hypoglycaemia require a professionally supervised plan before increasing activity or sharply reducing food intake. A personal sensor or meter does not replace diagnostic laboratory tests.
The Verdict
Main sources
The references below were accessed on 12 October 2026:
