HOMA-IR (insulin resistance)
Homeostasis model assessment of insulin resistance from fasting glucose and insulin
Sources last checked: 2026-10-27
HOMA-IR (insulin resistance)
Homeostasis model assessment of insulin resistance from fasting glucose and insulin
There is no universal cut-off: Matthews scaled the model so that normal-weight young adults average about 1, and published population cut-offs vary with ethnicity, age and the insulin assay. Not valid on insulin treatment or when β-cell function is severely reduced.
What is the HOMA-IR (insulin resistance)?
HOMA-IR is the homeostasis model assessment of insulin resistance, published by Matthews and colleagues in Oxford in 1985. It estimates insulin resistance from a single fasting glucose and insulin value; the constant 22.5 (or 405 with glucose in mg/dL) scales the result so that healthy, normal-weight young adults average about 1.
When to use it
- Research and epidemiology on insulin resistance
- Tracking insulin resistance over time in the same person with the same insulin assay
- Context in metabolic syndrome, PCOS or MASLD work-up where a fasting insulin is already available
When not to use it
- Patients on insulin or with markedly reduced β-cell function (e.g. long-standing type 2 or type 1 diabetes)
- As a diagnostic test for diabetes — that rests on glucose and HbA1c criteria
- Non-fasting samples
How it is calculated
HOMA-IR = fasting glucose (mmol/L) × fasting insulin (µU/mL) / 22.5 HOMA-IR = fasting glucose (mg/dL) × fasting insulin (µU/mL) / 405
Clinical pearls and limitations
- There is no universal cut-off: Matthews scaled the model so that normal-weight young adults average about 1, and published population cut-offs vary with ethnicity, age and the insulin assay. Not valid on insulin treatment or when β-cell function is severely reduced.
- There is no single validated cut-off; published thresholds range roughly from 1.7 to 3.0 depending on population and insulin assay.
- Insulin assays differ substantially between laboratories, so values from different labs are not directly comparable.
- The updated computer model HOMA2 gives different (non-linear) results; this calculator uses the original linear approximation.
- Insulin pmol/L ÷ 6 ≈ µU/mL (some labs use 6.945).
Frequently asked questions
What is a normal HOMA-IR?
By construction, around 1 in healthy normal-weight young adults. Values above roughly 2–3 are often reported as insulin resistance, but the threshold depends on the population and the assay.
What is the HOMA-IR formula in mg/dL?
Fasting glucose (mg/dL) × fasting insulin (µU/mL) / 405.
Does HOMA-IR work in people with diabetes?
Only with caution in early type 2 diabetes not treated with insulin; it is not meaningful on insulin therapy.
Evidence and guidelines
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
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<p><a href="https://medelix.ai/en/calculators/homa-ir-insulin-resistance">HOMA-IR (insulin resistance) calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.