What does it measure?
HOMA-IR combines fasting insulin and fasting glucose in a mathematical model. It estimates insulin resistance under fasting conditions and is widely used in research. The original HOMA1 equation and the later HOMA2 model are different, so a report should identify which calculation it uses. [1] [3] [4]
Before reading the calculation
- Inputs
- Fasting glucose and fasting insulin collected together.
- HOMA1 formula
- Insulin (µU/mL) × glucose (mmol/L) ÷ 22.5; with glucose in mg/dL, divide by 405 instead.
- Version
- HOMA2 is a different computer model; its results are not interchangeable with this simple equation.
- Model limits
- The simple HOMA1 formula is a historical approximation, not HOMA2. For HOMA2, the intended inputs are simultaneous plasma glucose and insulin; serum insulin needs a laboratory-validated conversion or an explicit limitation.
What can the result mean?
A higher HOMA-IR usually suggests more insulin resistance within the model. A lower result usually suggests less, but low insulin production can also make the number misleading. It does not diagnose diabetes and cannot describe every aspect of how muscles, liver, and other tissues respond to insulin. [1]
Fasting glucose and fasting insulin collected together.
- HOMA1 formula
- Insulin (µU/mL) × glucose (mmol/L) ÷ 22.5; with glucose in mg/dL, divide by 405 instead.
- Version
- HOMA2 is a different computer model; its results are not interchangeable with this simple equation.
- Model limits
- The simple HOMA1 formula is a historical approximation, not HOMA2. For HOMA2, the intended inputs are simultaneous plasma glucose and insulin; serum insulin needs a laboratory-validated conversion or an explicit limitation.
When is it useful, and how is it read?
HOMA-IR is most meaningful within a defined research or clinical assessment using fasting glucose and insulin together. It estimates a process rather than diagnosing diabetes. Unexpected results should send the discussion back to the input measurements, medicines, and established glucose tests. [1] [2]
Reading the results together
| Marker | What it adds |
|---|---|
| Glucose (Fasting) | The fasting glucose concentration. |
| Insulin | The matching fasting hormone concentration. |
| HOMA-IR | A model using both inputs. |
A change in the model can come from either input. Review those values and the sampling conditions before reading the score. [1] [6]
What can affect it?
The sample must meet the intended fasting conditions, and glucose and insulin should be taken together. Units, laboratory insulin methods, illness, and glucose-lowering treatment influence interpretation. Published thresholds vary by population and method; a universal optimal cutoff is not established. Injected insulin can make this insulin-based estimate inappropriate; a clinician must check whether the model applies. [1] [3] [5]
HOMA1 and HOMA2 are different calculations
The simple HOMA1 equation and the updated HOMA2 computer model are not interchangeable. Results should state which method was used; a change between methods is not automatically a change in your physiology. [3] [4]
Questions you might have
Can I use an insulin result from a different day?
That would not match the intended fasting glucose–insulin pair. The model describes the two values under the same fasting conditions. [1]
Does HOMA-IR have one universal ideal number?
No. Insulin assays, model version and the studied population affect interpretation. The result is an estimate, not a stand-alone diabetes diagnosis. [6]
What comes next?
Review the underlying glucose and insulin, HbA1c, blood pressure, lipids, and clinical history. Ask whether the estimate changes a practical decision. Routine insulin-resistance testing is not necessary for everyone, and no supplement should be prescribed solely to reach a HOMA-IR score. [2]
Which HOMA model was used, and does it change what we should do next?
The reference interval and units on your report are part of understanding your result. Understand units, reference intervals, and treatment targets.
Sources & references
Medical references & original research
- Matthews et al. — Homeostasis model assessment (original study, 1985)
- NIDDK — Insulin resistance and prediabetes
- University of Oxford — History of the HOMA models
- Levy et al. — Correct HOMA evaluation uses the computer program (PubMed, 1998)
- Wallace, Levy and Matthews — Use and Abuse of HOMA Modeling (2004)
- University of Oxford — HOMA model frequently asked questions
- Karnieli E, et al. Insulin stimulates glucose transport in isolated human adipose cells through a translocation of intracellular glucose transporters to the plasma membrane: a preliminary report. Hormone and Metabolic Research. 1986;18:867–868.
- Lopez JA, et al. Identification of a distal GLUT4 trafficking event controlled by actin polymerization. Molecular Biology of the Cell. 2009;20:3918–3929.
- Kanzaki M. Insulin receptor signals regulating GLUT4 translocation and actin dynamics (review). Endocrine Journal. 2006;53:267–293.
- MedlinePlus. Insulin in Blood.
- MedlinePlus. Blood Glucose Test.
- Cleveland Clinic. Insulin Resistance.
Books we consulted
References that informed our explanations of the test and its context.
- Pagana KD, Pagana TJ, Pagana TN. Mosby’s Diagnostic and Laboratory Test Reference. 14th ed. Elsevier; 2019.
Practical-section sources accessed: .
For general health education. Interpreting your result and deciding on tests or treatment requires your health context and a qualified clinician.
