Quick version
Insulin resistance means that the body's cells respond less well to insulin. The pancreas compensates by producing more insulin, which allows fasting glucose and HbA1c to remain within normal limits for a long time. The condition is often revealed instead through a pattern of subtle signs such as increased waist circumference, sweet cravings, fatigue after meals, skin changes (such as acanthosis nigricans and skin folds), elevated triglycerides, low HDL, rising blood pressure or fatty liver. Detecting these metabolic warning signs early provides good opportunities to reverse the development with the help of lifestyle changes.
Many people seek treatment for fatigue, an increasing waistline or a sweet tooth that has become harder to resist, but are still told that their blood sugar looks “normal”. This can feel contradictory. One possible explanation is insulin resistance – an early stage where the body needs more insulin than before to keep glucose levels in check, long before fasting glucose or HbA1c clearly deviate.
Insulin resistance before blood sugar rises – what signs can be present?
Insulin resistance means that the body's cells, especially in muscles, liver and fat tissue, respond less well to insulin. The pancreas then compensates by releasing more insulin, so that blood sugar can remain within the reference range for a period. This is why you can have an ongoing metabolic burden without a regular blood sugar test yet showing diabetes or even clear prediabetes.
This is also the reason why insulin resistance rarely gives a single clear symptom. Instead, it is often noticed through a pattern: changes in weight, blood lipids, blood pressure, skin or energy levels. Several of these signs are related to what is usually called metabolic syndrome.
Early signs of insulin resistance can be subtle
The most common early sign is not high blood sugar, but that the body starts to “work harder” in the background. For many, this manifests itself as abdominal obesity, especially if the waist circumference increases even though the weight has not changed much. Visceral fat, i.e. fat around the abdominal organs, is strongly linked to reduced insulin sensitivity.
Some notice more everyday signals. This may involve becoming unusually tired after meals, often feeling hungry again shortly after eating, or an increase in sweet cravings and snacking. Such symptoms are not specific enough to make a diagnosis, but they fit with the physiology that occurs when the insulin boost becomes high to keep glucose stable. This is a reasonable medical interpretation based on how compensatory hyperinsulinemia works, even though the symptoms themselves are not diagnostic.
Weight gain can also occur early, especially if it is around the stomach. Insulin resistance can lead to both rising blood sugar and weight gain. In practice, many people seek treatment first because their clothes fit differently or because they have more difficulty losing weight than before.
Skin changes that can signal insulin resistance
In some people, insulin resistance is visible on the skin before blood sugar has had time to rise clearly. A classic finding is acanthosis nigricans, darker, thickened and slightly velvety areas of skin, often in the neck, armpits or groin. This is mentioned in both diabetes and liver disease guidelines as a sign linked to insulin resistance.
Some also develop skin tags, small soft growths that are often on the neck or in the armpits. Skin folds are not as specific as acanthosis nigricans, but are often seen in conjunction with obesity, insulin resistance and metabolic effects. Here you need to be careful: skin changes can have other causes and should be assessed in their context.
If you see a new darker skin change in skin folds, it is not proof of diabetes, but it is a signal that deserves to be taken seriously. Especially if it comes together with an increased waist circumference, high blood fats or heredity for type 2 diabetes.
When blood fats, blood pressure or liver values change before glucose
Insulin resistance affects more than sugar metabolism. A common pattern is elevated triglycerides, lower HDL cholesterol and rising blood pressure, sometimes while fasting glucose is still normal. Blood fats can rise in insulin resistance or prediabetes, and dyslipidemia and hypertension are conditions that are associated with insulin resistance.
The liver is also affected early. Fatty liver, now often called MASLD, is often seen as the hepatic part of metabolic syndrome and is strongly linked to insulin resistance. A person can therefore have slightly elevated liver values or detect fatty liver on ultrasound without their blood sugar having yet reached the prediabetes threshold.
This is a common patient question: “Can I have insulin resistance even though my HbA1c is normal?” Yes, you can. HbA1c and fasting glucose do not always capture the early compensation phase, as the body can keep glucose normal for a while by producing more insulin.
Who is at higher risk of developing insulin resistance?
The strongest risk link is with overweight, especially central obesity. But insulin resistance does not only affect people with a high BMI. Heredity, low physical activity, previous gestational diabetes, polycystic ovary syndrome and certain blood lipid disorders also increase the risk.
This also applies to younger people. In children and adolescents, signs such as acanthosis nigricans, high blood pressure, blood lipid disorders and PCOS are used as markers for risk-based screening, which shows that insulin resistance can be present before classic hyperglycemia becomes apparent.
In everyday life, the risk profile often looks like this:
- Waist circumference increases faster than weight in general
- Type 2 diabetes is present in a parent or sibling
- Blood pressure or triglycerides have begun to rise
- You have had gestational diabetes or have been told that you have PCOS
- Liver values are slightly elevated or fatty liver has been discovered
- You move little and sit a lot during the workday
No single point is sufficient for diagnosis, but the more that are correct, the more reasonable it is to check your metabolic values.
How can test insulin resistance before diabetes develops?
In healthcare and research, there are different ways to estimate insulin resistance. The most accurate method is a so-called hyperinsulinemic-euglycemic clamp, but it is not used in general practice. In practice, blood tests and a risk profile are used.
The three established tests for identifying prediabetes are fasting glucose, HbA1c and glucose tolerance, also called OGTT. Different tests can capture different people, and someone may have normal fasting glucose but at the same time an HbA1c in the prediabetes range or an abnormal value during glucose load.
Fasting insulin and calculations such as HOMA-IR are sometimes used to estimate insulin resistance, but they are not standardized diagnostic tests in the same way as HbA1c or glucose load. They can still be valuable for understanding the early metabolic picture, especially together with blood lipids, waist circumference and liver samples. HOMA-IR is based on fasting glucose and fasting insulin and above all reflects the basal situation.
If you wonder when it is wise to test yourself, the answer is often: before you get clear symptoms of diabetes. If you wait until thirst, large amounts of urine and pronounced fatigue occur, the process has often been going on for a long time. Early testing is therefore less about “proving disease” and more about capturing a pattern while it is still possible to influence it effectively.
What can you do if several signs match?
There is good evidence that lifestyle measures can reduce the risk of insulin resistance progressing to prediabetes and type 2 diabetes. Weight treatment for overweight or obesity, medical nutrition therapy and physical activity as central interventions. Sleep is also now more clearly highlighted as part of the treatment for those at risk of diabetes.
It is often most helpful to start concretely. Change the focus from “perfect diet” to regularity: more movement during the week, less prolonged sitting, protein and fiber that fill you up better, and habits that make it easier to maintain a steady energy level. If liver values, blood fats or blood pressure have already started to deviate, it may be a sign that the body would benefit from early change.
Normal blood sugar is not always the end point of the assessment. Sometimes it is just a snapshot of whether the pancreas is still managing to compensate. The more crucial question is whether the rest of the body is already showing signs that the system is working under high load.
Detecting insulin resistance early is therefore not just about preventing diabetes. It may also provide a chance to catch the risk of fatty liver, lipid metabolism disorders and cardiovascular disease at a stage where small changes often have a greater effect than you think.
