What is the HOMA-IR score?
HOMA-IR is a number that estimates how resistant your body is to insulin, using only a fasting glucose and a fasting insulin taken from the same blood draw. It comes from the homeostasis model assessment, published in 1985, which treats glucose and insulin as two sides of a feedback loop: when cells resist insulin, the pancreas releases more to hold glucose steady, and both numbers drift up together.
In the original Diabetologia paper, the HOMA estimate of insulin resistance correlated strongly with the euglycemic clamp, the laborious research method that measures insulin sensitivity directly. That is why HOMA-IR became a common shortcut in studies. The same paper also flagged its limits, which come up below.
How do you calculate HOMA-IR?
Multiply fasting glucose by fasting insulin, then divide by a constant that depends on your glucose units:
- U.S. units: fasting glucose (mg/dL) × fasting insulin (µIU/mL) ÷ 405
- International units: fasting glucose (mmol/L) × fasting insulin (µIU/mL) ÷ 22.5
The two constants say the same thing: 405 is 22.5 multiplied by 18, the factor that converts glucose from mmol/L to mg/dL. The Spanish EPIRCE study uses the mmol/L version.
Here are worked examples:
| Fasting glucose | Fasting insulin | Calculation | HOMA-IR |
|---|---|---|---|
| 88 mg/dL | 5 µIU/mL | 88 × 5 ÷ 405 | 1.09 |
| 90 mg/dL | 10 µIU/mL | 90 × 10 ÷ 405 | 2.22 |
| 95 mg/dL | 12 µIU/mL | 95 × 12 ÷ 405 | 2.81 |
| 108 mg/dL | 20 µIU/mL | 108 × 20 ÷ 405 | 5.33 |
| 5.0 mmol/L | 10 µIU/mL | 5.0 × 10 ÷ 22.5 | 2.22 |
Notice the second and third rows. Both glucose values are normal, yet the insulin needed to hold them there differs, and the score captures that. Our page on the fasting insulin test explains why insulin often climbs first, and the fasting glucose test page covers the other input.
What score bands are used to flag insulin resistance?
There is no single agreed cutoff, and the bands used in research shift with the population studied. The EPIRCE study of 2,459 Spanish adults is a useful example because it reports several:
| Population and method | HOMA-IR cutoff |
|---|---|
| Spanish men without diabetes, optimal match for metabolic syndrome (ATP III criteria) | 1.85 |
| Spanish adults, match for metabolic syndrome (IDF criteria) | 2.05 |
| Spanish adults, 90th percentile of the population | 3.46 |
| Other published populations reviewed by the study, including the U.S., Japan and Iran | about 1.55 to 3.8 |
The authors note that cutoffs differ by ethnicity and by how insulin is measured, which is one reason a number from a study in one country does not transfer neatly to a man in San Gabriel. Ultimate Male has not published a clinic threshold; your provider reads the score in context rather than against one line.
In practice, a score near the bottom of that range with normal glucose, triglycerides and waist size is reassuring. A score well above 3 alongside a large waist, high triglycerides or low HDL points to insulin resistance worth acting on. Our page on metabolic syndrome in men explains how those markers cluster.
Why is HOMA-IR an estimate, not a diagnosis?
HOMA-IR rests on a single fasting sample and a lab insulin assay, and both add noise. The 1985 paper reported a coefficient of variation of about 31% for the insulin resistance estimate, meaning repeat calculations on the same person can differ noticeably. MedlinePlus adds that insulin reference ranges vary between labs and that some insulin tests measure injected insulin differently.
The NIDDK is direct about this: insulin resistance testing is primarily used in research, and prediabetes is diagnosed with glucose-based tests. HOMA-IR works as an early-warning signal and a way to track change in the same person, not as a label.
What moves the score?
Anything that improves insulin sensitivity lowers HOMA-IR, and anything that worsens it pushes the score up. The NIDDK lists excess weight or a large waist, inactivity, smoking, a family history of diabetes, sleep apnea and some medicines such as glucocorticoids among the factors that raise insulin resistance.
The score also tends to move well before glucose does. In the Whitehall II study, HOMA insulin sensitivity fell steeply during the five years before people were diagnosed with diabetes, while fasting glucose only rose sharply in the final three. That makes a rising HOMA-IR a useful prompt to act while there is still time. High triglycerides often rise in step with it.
Getting a HOMA-IR score at Ultimate Male
A HOMA-IR score needs a fasting insulin and a fasting glucose from the same morning draw. Glucose is part of the comprehensive metabolic panel, but fasting insulin is not on the clinic’s published panel lists, so ask on the free phone call whether adding it makes sense for you.
Draws happen on site at San Gabriel and Downey, with results in 24 to 48 hours. Your provider calculates the score, reads it with your waist, lipids, A1c and history, and explains whether it supports lifestyle changes, a repeat in a few months, or a supervised medical weight loss program. For the full clinical picture, see our page on insulin resistance in men.
