Risk guide
HOMA-IR: measuring insulin resistance before diabetes appears
HOMA-IR estimates insulin resistance from a single fasting blood draw. It often turns abnormal years before fasting glucose or HbA1c drift out of range, which makes it a useful early-warning number.
What it needs
- • Fasting plasma glucose
- • Fasting insulin
- • Optionally fasting triglycerides, for the TyG index
How it is calculated
HOMA-IR is fasting insulin (µU/mL) multiplied by fasting glucose (mg/dL), divided by 405 — or divided by 22.5 when glucose is in mmol/L. Vitals handles the unit conversion and logs which units you entered.
How to read the result
Values around 1.0 are typical of good insulin sensitivity. Above roughly 2.0 suggests emerging resistance and above 2.9 is commonly used as a cut-off for significant resistance, though thresholds vary between populations and assays. Because assays differ, the trend in your own results matters more than a single absolute figure.
The companion indices
HOMA-B estimates beta-cell function, QUICKI is a sensitivity index that behaves more stably at extremes, and TyG uses triglycerides and glucose when an insulin result is unavailable. Vitals reports all four side by side.
What changes it
Weight loss, resistance training, sleep and reduced refined-carbohydrate intake all move insulin sensitivity. The what-if simulator lets you recalculate against hypothetical values without touching your official record.
Source
Matthews DR et al., Diabetologia 1985;28:412-419
This guide is educational. It is not a diagnosis and does not replace a conversation with a qualified clinician.
Know your risk, take action
Create a free account and get your first risk assessment in under ten minutes. No card required.