AIS Health Check · Insulin resistance testing
HOMA-IR vs HOMA2-IR: what is the difference?
Similar names. Different calculations. Here is what that means for your results.
Both estimate insulin resistance using fasting blood measurements. HOMA2-IR is Oxford’s updated model, with a more detailed calculation.
AIS Health Check uses HOMA2-IR. Explore our insulin resistance test with doctor interpretation.
HOMA-IR vs HOMA2-IR: the short answer
HOMA stands for Homeostasis Model Assessment. The letters IR mean insulin resistance.
Insulin helps move glucose, or sugar, from your blood into cells. Insulin resistance means your cells respond less effectively to insulin.
HOMA-IR
Usually means the original HOMA1-IR estimate. It uses a simple formula with fasting glucose and fasting insulin.
HOMA2-IR
Uses an updated computer model developed by the University of Oxford. It represents the relationship between glucose and insulin in greater detail.
Both are calculated estimates, rather than direct measurements of insulin resistance. Their numbers and interpretation thresholds are not interchangeable. [1] [2]
New to the subject? Start with our guide to insulin resistance, symptoms and testing.
HOMA-IR and HOMA2-IR compared
| Feature | HOMA-IR / HOMA1-IR | HOMA2-IR |
|---|---|---|
| Calculation | A simple mathematical formula | A more detailed computer model |
| Blood measurements | Fasting glucose and insulin | Fasting glucose with insulin or C-peptide |
| How the body is represented | A simplified approximation | Accounts for additional physiological relationships |
| Fasting needed? | Yes | Yes |
| Universal normal range? | No | No |
| Can it diagnose diabetes alone? | No | No |
| Can results be directly compared? | No. Always identify the model used. | |
Based on Oxford’s model documentation and the authors’ methodological review. [1] [2] [3]
How does a HOMA-IR calculator work?
Many online HOMA-IR calculators use the original formula:
Fasting glucose (mmol/L) × fasting insulin (mIU/L) ÷ 22.5
For example, glucose of 5.0 and insulin of 10 give approximately 2.22. This is a HOMA1-IR result, not a HOMA2-IR result.
That example only demonstrates the arithmetic. It does not provide a diagnosis or a normal-range comparison.
How is HOMA2-IR calculated?
HOMA2-IR requires the updated computer model rather than that simple formula. Your glucose and insulin-related measurements are entered using the correct units.
The model can use insulin or C-peptide with glucose. Your report should identify which measurement was used. [1]
You cannot reliably convert HOMA1-IR into HOMA2-IR by dividing by one number. The original blood measurements need recalculating using the correct model.
Is HOMA2-IR more accurate than HOMA-IR?
HOMA2 is a more detailed representation of the body’s glucose–insulin relationship. Oxford’s update accounts for features omitted from the simplified HOMA1 formula. These include differences between the liver’s response and other tissues’ responses. [2]
However, “updated” does not mean a perfect measurement for every patient. Fasting conditions, laboratory methods and clinical circumstances still affect interpretation.
HOMA estimates are useful in research and can support clinical assessment. They do not replace a full assessment of your metabolic health. [1]
Use the correct model consistently and interpret it with your other results. A more sophisticated calculation still needs a clinician’s judgement.
HOMA-IR and HOMA2-IR ranges: what does my result mean?
Higher results generally suggest your body responds less effectively to insulin. However, there is no universal “normal range” for either calculation. Laboratory methods and the population studied affect the comparison numbers. [3]
Our insulin resistance test uses the updated HOMA2-IR calculation. We interpret it alongside your other blood results and clinical information.
A general guide to your HOMA2-IR result
| HOMA2-IR result | What this may mean |
|---|---|
| 2.0 or below | Insulin resistance is still possible. Some studies identified it at lower levels. This is not automatically a normal result. |
| Above 2.0 | Your result may suggest insulin resistance. Your clinician checks your other blood results before drawing conclusions. |
This general guide reflects the research comparisons below. The number 2.0 is not a universal diagnostic threshold. It does not define mild, moderate or severe insulin resistance.
How do the original and updated ranges compare?
One Brazilian study calculated both HOMA1-IR and HOMA2-IR. Its insulin resistance thresholds differed between the two models. [4]
| Calculation | Not above this study’s threshold | Above this study’s insulin resistance threshold |
|---|---|---|
| Original HOMA-IR / HOMA1-IR | 2.7 or below | Above 2.7 |
| Updated HOMA2-IR | 1.8 or below | Above 1.8 |
These thresholds came from the study’s healthy reference group. They are not universal diagnostic rules or validated “normal” ranges. A result below them cannot reliably rule out insulin resistance.
HOMA2-IR comparison numbers in different populations
Researchers chose a comparison number, called a cut-off, for each study. Results above it were considered potentially consistent with insulin resistance.
| People studied | Comparison number used | Study |
|---|---|---|
| European rural population | 1.21 | Radikova, 2006 [5] |
| Brazilian adults | Above 1.8 | BRAMS, 2009 [4] |
| Adults in Maracaibo, Venezuela | 1.95 | Bermúdez, 2014 [6] |
| Qatari adults: calculation using insulin | 1.128 or above | Qatar Biobank, 2025 [7] |
| Qatari adults: calculation using C-peptide | 1.307 or above | Qatar Biobank, 2025 [7] |
Your nationality alone does not determine which comparison applies. Studies used different laboratory methods and definitions of insulin resistance. Your clinician considers whether a study’s findings fit your circumstances.
These comparisons must not be combined into a universal severity scale. Read our full HOMA2-IR interpretation guide for further explanation.
Does a lower HOMA2-IR result mean improvement?
Not necessarily, if your previous result used HOMA1-IR. The change may reflect the calculation method rather than improved insulin sensitivity.
Compare repeat results using the same model and similar fasting conditions. Using the same laboratory also helps reduce differences between measurements.
What does an insulin resistance blood test include?
An assessment can combine several measurements, each answering a different question:
Fasting glucose
How much sugar is in your blood after fasting?
Fasting insulin
How much insulin is circulating alongside that glucose level?
C-peptide
What does the result suggest about your own insulin production?
HbA1c
What has your average blood sugar been over recent months?
HOMA2-IR adds an estimate calculated from suitable fasting measurements. HbA1c is not an input into either HOMA-IR calculation.
Do I need to fast?
Yes. Follow your provider’s instructions, usually fasting for eight to twelve hours. Plain water is generally allowed.
Tell your provider about medicines, supplements and recent illness. Do not stop prescribed medicines without advice. Seek individual fasting advice if you take medicines that lower blood sugar.
HbA1c alone does not require fasting. The fasting requirement relates to glucose, insulin and the HOMA calculation.
Looking for a HOMA-IR test in the UK?
AIS Health Check uses the updated HOMA2-IR calculation for its insulin resistance assessment. Your blood results are considered together, with a doctor’s interpretation.
Explore the panel, available locations and preparation details before booking.
View the insulin resistance testFrequently asked questions
Are HOMA-IR and HOMA2-IR different blood tests?
They are different calculations using fasting blood measurements. The blood sampling may be similar, but the calculation method differs.
Can I calculate HOMA2-IR with the standard HOMA-IR formula?
No. The standard formula produces HOMA1-IR. HOMA2-IR requires the updated model.
Is HOMA2-IR always lower than HOMA-IR?
Do not assume a fixed relationship between the results. The difference depends on the underlying blood measurements and calculation inputs.
Can either test diagnose pre-diabetes or diabetes?
No. Glucose and HbA1c have separate clinical diagnostic criteria. Your clinician may need further testing to confirm a diagnosis.
Can normal HbA1c exclude insulin resistance?
No. HbA1c measures average blood sugar, rather than insulin sensitivity. Insulin production can increase while blood sugar remains controlled.
Should insulin and C-peptide calculations be treated as identical?
No. Always identify the input used. Kidney function and other clinical factors can affect interpretation, particularly with C-peptide.
Is HOMA2-IR appropriate for everyone?
No. Pregnancy, insulin treatment and some illnesses need different assessment. Your clinician should decide whether the calculation is suitable.
Keep exploring your metabolic health
References
- Wallace TM, Levy JC, Matthews DR. Use and Abuse of HOMA Modeling. Diabetes Care. 2004;27:1487–1495.
- University of Oxford: history of the HOMA model.
- University of Oxford: HOMA calculator frequently asked questions.
- Geloneze et al. HOMA1-IR and HOMA2-IR: Brazilian Metabolic Syndrome Study. 2009.
- Radikova et al. Insulin sensitivity indices: proposed cut-off points. 2006.
- Bermúdez et al. HOMA2-IR in a Venezuelan population. 2014.
- Aliyu et al. Insulin resistance indices in Qatar Biobank. 2025.
General patient information. Interpretation should reflect your individual circumstances.