How Insulin Resistance Is Measured
| Test | Formula / Method | Normal | Notes |
|---|---|---|---|
| Fasting insulin | Blood test (mIU/L) | <15 mIU/L | Rises before glucose — early marker |
| Fasting glucose | Blood test (mmol/L) | <6.1 mmol/L | Often normal in early IR |
| HOMA-IR | Fasting insulin × fasting glucose / 22.5 | <2.0 | Best single measure of IR in clinical practice |
| HbA1c | % of glycated Hb | <42 mmol/mol (<6%) | Reflects last 2–3 months average glucose |
| OGTT | Glucose at 0 and 2 hours | <6.1 / <7.8 mmol/L | Gold standard for pre-diabetes staging |
Conditions Associated with Insulin Resistance
Type 2 diabetes, PCOS, non-alcoholic fatty liver disease (NAFLD), metabolic syndrome, hypertension, dyslipidaemia, and polycystic ovary syndrome. Central obesity is the most powerful predictor.
Improving Insulin Sensitivity
- Weight loss (even 5–10% significantly reduces insulin resistance)
- Aerobic and resistance exercise — both independently improve insulin sensitivity
- Low-glycaemic index diet — reduces glucose spikes and insulin demand
- Reducing visceral fat (waist circumference <94 cm men; <80 cm women targets)
- Metformin — first-line medication that reduces hepatic glucose output and improves sensitivity
- GLP-1 receptor agonists (liraglutide, semaglutide) — reduce IR and promote weight loss
Waist Measurement Matters MostWaist circumference is a better predictor of insulin resistance than BMI. Measure at the level of the navel — >94 cm (men) or >80 cm (women) indicates increased risk.
Can you have insulin resistance with normal glucose?
Yes. Fasting glucose may be normal for years while insulin levels rise compensatorily. HOMA-IR and fasting insulin are more sensitive early markers than glucose alone.
Is insulin resistance reversible?
Yes, in many people. Weight loss, exercise, and dietary change can dramatically improve insulin sensitivity. Early intervention prevents progression to type 2 diabetes.
What is metabolic syndrome?
A cluster of metabolic risk factors including central obesity, insulin resistance, hypertension, dyslipidaemia (high triglycerides, low HDL), and raised fasting glucose. Presence of 3 or more of the 5 criteria confirms the diagnosis.
Does PCOS cause insulin resistance?
Yes. Insulin resistance is present in 50–70% of women with PCOS, regardless of weight. It drives excess androgen production, anovulation, and the metabolic complications of PCOS.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.