HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) is a simple marker of insulin resistance using just two fasting blood values: glucose and insulin. Introduced by Matthews et al. in 1985.

How is HOMA-IR calculated?

Classic formula: HOMA-IR = (fasting insulin in µU/mL × fasting glucose in mg/dL) / 405. In SI units: (insulin µU/mL × glucose mmol/L) / 22.5. Both produce the same index.

What values are considered abnormal?

Below 1.5: normal. 1.5 to 1.99: mild insulin resistance. 2.0 to 2.89: meaningful insulin resistance. 2.9 and above: severe insulin resistance with a high risk of type 2 diabetes.

Who should measure HOMA-IR?

Useful in PCOS, fatty liver, obesity, a family history of diabetes, or borderline HbA1c. The test is cheap, fast and provides an early signal — before fasting glucose itself becomes abnormal.

What can distort the value?

Acute illness, stress, recent meals, glucocorticoids, pregnancy or too short a fasting window (under 8 hours) can shift both glucose and insulin. Repeat the test in a calm baseline state if in doubt.

How can HOMA-IR be lowered?

Weight loss, regular physical activity — combine resistance and aerobic training — carbohydrate-aware nutrition and adequate sleep measurably improve insulin sensitivity. First effects often appear within a few weeks.

HOMA-IR Calculator Guide: Spot Insulin Resistance Early

Fasting glucose looks fine — yet something is off. HOMA-IR fills that gap. Two simple fasting labs reveal how hard the pancreas is working to keep blood sugar in range.

This guide explains the formula, the risk bands, and what to do about an elevated value — before insulin resistance becomes type 2 diabetes.

The formula: two values, one index

Matthews and colleagues introduced the index in 1985. The idea: an insulin-resistant body secretes more fasting insulin to keep blood sugar stable. The product of both values exposes that extra work.

HOMA-IR = (insulin µU/mL × glucose mg/dL) / 405

In SI units (mmol/L): HOMA-IR = (insulin µU/mL × glucose mmol/L) / 22.5. The two divisors differ only because 22.5 × 18 = 405 — the glucose conversion factor.

Example: glucose 90 mg/dL, insulin 8 µU/mL → (8 × 90) / 405 = 1.78. That sits in the "mild insulin resistance" range.

Risk bands at a glance

HOMA-IR bands

< 1.5Normal

1.5 – 1.99Mild insulin resistance

2.0 – 2.89Insulin resistance

≥ 2.9Severe

Cut-offs come from cross-sectional studies (e.g. Geloneze 2009). They are a useful guide rather than a strict rule — lab, age and ethnicity can shift the interpretation.

Why HOMA-IR beats fasting glucose alone

A fasting glucose of 95 mg/dL still looks "normal". But if it takes 15 µU/mL of insulin to keep it there, the pancreas is already fighting a losing battle. The HbA1c often catches up only years later.

HOMA-IR exposes that silent pre-phase — and that is exactly where lifestyle interventions have the largest leverage.

Who should test?

→Overweight or obesity (BMI ≥ 25)
→Polycystic ovary syndrome (PCOS)
→Non-alcoholic fatty liver disease
→Family history of type 2 diabetes
→Borderline HbA1c or fasting glucose

If any of these apply, an early measurement pays off. The test is inexpensive and gives a clear direction.

What can throw the value off

Before the test

→ Fast fully for 8–12 hours
→ No acute infection or high fever
→ No short-term steroid therapy
→ Get a proper night of sleep beforehand

In pregnancy other reference values apply — HOMA-IR does not replace an oral glucose tolerance test there.

Calculate your HOMA-IR

Enter fasting glucose and fasting insulin — the calculator returns the index and band.

Open the HOMA-IR Calculator

What to do about an elevated HOMA-IR

Insulin resistance is reversible, especially in the early stages. Three levers do most of the work:

1.Activity: 150 minutes of moderate aerobic exercise per week plus two resistance sessions. Muscle cells become much more insulin-sensitive.
2.Weight loss: Even 5–7 % body-weight reduction often lowers HOMA-IR noticeably.
3.Nutrition: Fewer refined carbs, more fiber, adequate protein. Cutting sugary drinks is the biggest single lever.

For markedly elevated values, metformin may be added on medical advice. Lifestyle remains the foundation.

Takeaway

HOMA-IR is a simple but underused marker. Two lab values are enough to expose the silent prelude to type 2 diabetes — often years before glucose rises.

For elevated values the message is rarely dramatic but always clear: move more, lose some weight, eat better. Early action pays off.