Insulin resistance means your body has to work harder to keep blood sugar steady. Here's how it develops, the signs, and how it's checked.
Insulin resistance is when the cells in your muscles, liver and fat don't respond as well as they should to insulin, the hormone that moves sugar from your blood into your cells. To compensate, your body makes more insulin to keep blood sugar steady. It often causes no obvious symptoms for years, but over time it raises the risk of prediabetes, type 2 diabetes and heart disease, which is why it's worth knowing about.
What insulin normally does
When you eat, carbohydrates are broken down into glucose, a type of sugar that enters your bloodstream. Your pancreas responds by releasing insulin. Insulin acts like a key, signalling your muscle, liver and fat cells to take glucose in, either to use for energy straight away or to store for later.
When this system works well, blood sugar rises a bit after a meal and then settles back down. Your body does this all day without you noticing.
What happens with insulin resistance
With insulin resistance, the cells don't respond to that signal as readily. The pancreas makes up for it by producing more insulin, and for a while, that works. Blood sugar stays in the normal range, but only because insulin levels are running higher than usual.
Over time, the pancreas may struggle to keep up. Blood sugar starts to creep higher, first into the prediabetes range and, for some people, eventually into type 2 diabetes. Insulin resistance is also linked with high blood pressure, unhealthy blood fats, fatty liver and heart disease. The good news is that this progression isn't inevitable, and it tends to happen slowly enough to be picked up.
Who's more likely to develop it
Insulin resistance is common, and several factors raise the chances.
- Carrying extra weight around the waist, which is more closely linked to insulin resistance than weight elsewhere.
- Low physical activity, since active muscles are one of the main places glucose is used.
- A family history of type 2 diabetes.
- Getting older, as insulin sensitivity tends to fall with age.
- Polycystic ovary syndrome (PCOS) or a history of diabetes in pregnancy.
- Short or poor sleep and ongoing stress.
- Certain backgrounds, including Aboriginal and Torres Strait Islander, Pacific Islander, South Asian and some other communities, who have a higher risk of type 2 diabetes.
You can have insulin resistance without being overweight, and many people who carry extra weight don't have it. It's a metabolic pattern, not something you can always see.
Signs you might notice
Often there are none, which is why it's easy to miss. When signs do appear, they can include a growing waistline, darker, velvety patches of skin in folds such as the neck or armpits, and skin tags.
Some people also describe feeling tired or sleepy after meals, or feeling shaky and hungry when they go too long without eating. These symptoms are common and have many other causes, so they're a reason to get checked rather than a diagnosis in themselves. If an afternoon energy crash sounds familiar, you might also find why do I crash in the afternoon useful.
How it's checked
There isn't one standard test for insulin resistance in everyday practice. Instead, doctors usually look at a group of markers that together show how your body is handling glucose and fats. These commonly include fasting glucose, HbA1c (which reflects average blood sugar over roughly the past few months) and a lipid profile, along with your waist measurement and blood pressure.
Sometimes an oral glucose tolerance test is used, where blood sugar is measured before and after a sugary drink. Fasting insulin can also be measured, but results vary between labs and aren't always straightforward to interpret, so they should be read by a doctor alongside everything else. There's a fuller explanation in metabolic blood tests explained.
What influences insulin sensitivity
Insulin sensitivity responds to everyday habits. Regular physical activity, including both aerobic exercise and strength training, helps muscles take up glucose. Breaking up long periods of sitting helps too.
Sleep and stress matter more than many people realise, as short sleep can make the body less responsive to insulin. Eating patterns built around vegetables, fibre, protein and minimally processed foods, and keeping alcohol moderate, are all part of the picture. What's realistic and appropriate is different for everyone, which is where an individual assessment helps.
When to talk to a doctor
It's worth getting checked if you have a family history of type 2 diabetes, carry weight around your middle, have PCOS, had diabetes in pregnancy or have noticed darker patches of skin in body folds. See a doctor promptly if you have increased thirst, are passing more urine, have blurred vision, unexplained weight loss or sores that are slow to get better. If you have chest pain, trouble breathing or feel faint, call 000.
How UHD BioHealth can help
UHD BioHealth is a doctor-led telehealth service available across Australia. You start with a detailed online questionnaire, and an AHPRA-registered doctor reviews it within 24 hours. Where it's useful, your doctor will recommend bloodwork you can do locally, then you receive a written personalised plan with every cost listed before you pay anything, checked by a second, independent doctor, with follow-up care along the way. See what a doctor looks at for metabolic health.
Common questions
Can you have insulin resistance with normal blood sugar?
Yes. In the early stages, your pancreas makes extra insulin to keep blood sugar in the normal range. That's why insulin resistance can go unnoticed for years before blood sugar tests start to change.
Is insulin resistance the same as diabetes?
No. Insulin resistance is a state where your body responds less well to insulin. It can lead to prediabetes and type 2 diabetes over time, but many people with insulin resistance don't have diabetes.
Can insulin resistance improve?
Insulin sensitivity isn't set in stone. Regular physical activity, sleep, eating patterns and body composition all influence it, and it can change over time. A doctor can help you understand where you stand and what's worth focusing on.
Doing the right things. Nothing moves.
An in-depth health questionnaire covering your history, symptoms, medications and lifestyle, read by an AHPRA-registered doctor within 24 hours. Bloodwork where it's needed, and a written plan before you pay anything.
General health information only, not medical advice. Complete our questionnaire and a doctor will assess whether a consult is right for you. Individual needs and outcomes vary. In an emergency, call 000.
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