HOMA-IR: how to calculate it, the normal range and what a high score means
HOMA-IR (insulin resistance index) (HOMA-IR) · Calculated from fasting insulin and fasting glucose (often ordered with a metabolic or diabetes panel) · reported in Unitless ratio (calculated from insulin in uIU/mL or mIU/L and glucose in mg/dL or mmol/L)
HOMA-IR (homeostatic model assessment of insulin resistance) is a number calculated from two fasting blood tests, insulin and glucose, that estimates how hard your pancreas has to work to keep your blood sugar normal. The formula in US units is fasting insulin (uIU/mL) multiplied by fasting glucose (mg/dL), divided by 405. A lean, insulin-sensitive adult typically scores around 1.0; a score of 2.0 to 2.9 is borderline and a score of 3.0 or more is the cut-off most US studies use for insulin resistance, although labs and research groups set the line anywhere from 1.7 to 3.8.
The point of the test is that insulin resistance shows up years before blood sugar does. When muscle, liver and fat cells stop responding well to insulin, the pancreas compensates by making more of it, so fasting insulin climbs while glucose stays normal. A fasting glucose of 92 mg/dL with an insulin of 5 gives a HOMA-IR of 1.1; the same glucose with an insulin of 18 gives 4.1. Both people have a normal glucose and a normal A1C, but the second is well along the road to prediabetes, fatty liver and metabolic syndrome.
HOMA-IR is a research tool that has moved into clinical practice, and it has real limits. It depends on a fasting insulin assay that is not standardized between laboratories, it is invalid in anyone who takes insulin or has lost most of their insulin-producing cells (type 1 diabetes, long-standing type 2), and a single result can swing by 20 to 30 percent from day to day. It is best read as a trend alongside triglycerides, HDL, waist size, ALT and A1C rather than as a diagnosis on its own.
HOMA-IR at a glance
- Formula (US units): fasting insulin (uIU/mL) x fasting glucose (mg/dL) / 405. In SI units: insulin (uIU/mL) x glucose (mmol/L) / 22.5.
- Optimal: below 1.0. Normal in healthy adults: roughly 0.5-1.9. Borderline: 2.0-2.9. Insulin resistant: 3.0 and above (some labs use 2.0 or 2.5, some studies 3.8).
- A high HOMA-IR usually comes from excess abdominal fat, inactivity, poor sleep, PCOS or fatty liver; it often precedes prediabetes by 5 to 10 years.
- A low HOMA-IR (under 0.5) is normal in lean, active people; it only matters if insulin is low because the pancreas is failing, which shows up as a high glucose.
- Not valid in people on insulin, in type 1 diabetes, or when fasting glucose is above about 250 mg/dL.
- Next step: weight loss, exercise and sleep lower it within weeks to months; recheck fasting insulin and glucose after 3 to 6 months of changes.
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What HOMA-IR measures
HOMA-IR models the feedback loop between the liver and the pancreas during an overnight fast. In a fasting state, the liver releases glucose and the pancreas releases just enough insulin to hold it steady. If the liver and muscles are resistant to insulin, more insulin is needed to achieve the same glucose, so the product of the two numbers rises. The constant 405 (or 22.5 in SI units) is simply the product for an idealised, insulin-sensitive young adult, which sets the normal value at 1.0.
The model was published by Matthews and colleagues in Oxford in 1985 and validated against the hyperinsulinemic-euglycemic clamp, the gold-standard research test, with a correlation of about 0.7 to 0.9. An updated computer version, HOMA2, accounts for glucose loss through the kidneys and the liver's own glucose output and gives somewhat lower numbers, so HOMA1 and HOMA2 results and their cut-offs are not interchangeable. Most consumer and clinic reports use the original formula.
Because insulin has a half-life of only a few minutes and is secreted in pulses, a single fasting insulin varies by 20 to 30 percent from day to day in the same person, and insulin assays from different manufacturers can differ by a similar amount. The sample must be a true 8 to 12 hour fast with no coffee, nicotine or exercise beforehand, and it should not be taken during acute illness or within a few days of a steroid injection. Averaging two or three results gives a far more reliable picture than one.
Normal range for HOMA-IR
Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.
| Group | Typical range (Unitless ratio (calculated from insulin in uIU/mL or mIU/L and glucose in mg/dL or mmol/L)) | Notes |
|---|---|---|
| Optimal insulin sensitivity | Below 1.0 | Typical of lean, active adults with fasting insulin under 5 uIU/mL. The original model defines 1.0 as normal. |
| Normal, healthy adults | About 0.5-1.9 | Most non-diabetic adults with a healthy waist size. Labs differ; some print a cut-off of 2.0, 2.5 or 3.0 as the upper limit of normal. |
| Borderline / early insulin resistance | 2.0-2.9 | Common in people with excess abdominal fat, PCOS or fatty liver and still-normal glucose. In US population data (NHANES) a value of about 2.7-2.9 marks the top quarter of non-diabetic adults. |
| Insulin resistant | 3.0 and above | The cut-off used in most US studies; a value of 3.8 was proposed for Mexican-American adults and lower values (1.7-2.5) in some European and Asian populations. |
| Marked insulin resistance | Above 5 | Usually with obesity, metabolic syndrome, severe fatty liver, prediabetes or early type 2 diabetes; fasting insulin is typically over 20 uIU/mL. |
| Adolescents (puberty) | Normal up to about 3.2 | Insulin resistance rises physiologically in puberty and falls again by late adolescence; adult cut-offs over-diagnose teenagers. |
| Pregnancy | Rises through pregnancy, often 2-3 in the third trimester | Placental hormones cause physiological insulin resistance; HOMA-IR is not used to diagnose gestational diabetes. |
| Not valid | Type 1 diabetes, insulin treatment, fasting glucose above about 250 mg/dL | The model assumes a functioning pancreas; when insulin output is failing a low HOMA-IR is misleading. |
High HOMA-IR
A high HOMA-IR means your pancreas is producing more insulin than normal to keep your fasting glucose in range: your cells are responding to insulin less well than they should. At 2 to 3 this is usually a lifestyle signal and is reversible; at 3 to 5 it typically comes with other features of metabolic syndrome (a waist over 40 inches in men or 35 in women, triglycerides over 150 mg/dL, HDL under 40 or 50, blood pressure over 130/85) and a raised ALT from fat in the liver; above 5 the pancreas is under heavy strain and prediabetes or diabetes is often already present or close.
The main consequences of insulin resistance are not the number itself but what it drives: a two to four fold higher risk of type 2 diabetes over the following decade, fatty liver disease, higher triglycerides and lower HDL, higher blood pressure, PCOS in women, and a higher long-term risk of heart disease. High fasting insulin also makes it harder to lose weight because insulin promotes fat storage and blocks fat release.
A single high value should be confirmed. Insulin rises with a short or broken fast, caffeine, stress, poor sleep the night before, acute illness, steroid medication and some antipsychotics, and the insulin assay itself varies between labs. Two fasting measurements a few weeks apart, read with triglycerides, HDL, A1C and ALT, give a much more dependable answer than one.
Common causes
Excess abdominal (visceral) fat
Fat inside the abdomen releases free fatty acids and inflammatory signals that block insulin signalling in the liver and muscle. Waist circumference tracks HOMA-IR more closely than BMI; a 10 percent weight loss typically lowers HOMA-IR by 30 to 50 percent.
Physical inactivity
Muscle takes up about 80 percent of the glucose cleared after a meal, and inactive muscle is insulin resistant within days. Even a week of bed rest raises HOMA-IR measurably; regular training reverses it.
Polycystic ovary syndrome (PCOS)
About 70 percent of women with PCOS are insulin resistant regardless of weight, and high insulin in turn drives the ovaries to make more testosterone. HOMA-IR of 2 to 4 is typical.
Non-alcoholic fatty liver disease
Fat in the liver makes it resistant to insulin's signal to stop releasing glucose, so fasting insulin climbs. A high HOMA-IR with a raised ALT or GGT should prompt a liver ultrasound.
Prediabetes and type 2 diabetes
Insulin resistance precedes and underlies most type 2 diabetes. As fasting glucose creeps above 100 mg/dL with insulin still high, HOMA-IR climbs above 4 or 5; once the pancreas tires and insulin falls, the number paradoxically drops while glucose rises.
Short or poor-quality sleep and sleep apnea
Restricting sleep to 4 to 5 hours for a few nights reduces insulin sensitivity by 20 to 25 percent in healthy volunteers. Untreated obstructive sleep apnea has a similar effect through intermittent low oxygen and cortisol release.
Medications
Glucocorticoids (prednisone, dexamethasone, high-dose inhaled or injected steroids), atypical antipsychotics (olanzapine, clozapine), some HIV protease inhibitors, thiazide diuretics, beta-blockers and tacrolimus all raise insulin resistance. Steroids can double HOMA-IR within days.
Diet high in refined carbohydrate, sugar-sweetened drinks and excess calories
Sustained calorie surplus, fructose-rich drinks and high-glycemic eating promote liver fat and raise fasting insulin; the effect is mostly through weight gain and liver fat rather than carbohydrate itself.
Hormonal conditions
Cushing's syndrome (excess cortisol), acromegaly (excess growth hormone), untreated hypothyroidism, and high testosterone in women raise insulin resistance; pregnancy and puberty do so physiologically.
Chronic inflammation, smoking and genetic forms
Rheumatoid arthritis, psoriasis, chronic kidney disease and smoking modestly raise HOMA-IR. Rare inherited lipodystrophies and insulin-receptor mutations cause extreme values (often over 10) with a lean body.
Symptoms that can go with it
- Often none; most people with a HOMA-IR of 2 to 4 feel well, which is why it is measured
- Weight gain around the waist that is hard to shift, and strong hunger or cravings for carbohydrate, especially mid-afternoon or after meals
- Energy dips, drowsiness or brain fog an hour or two after eating
- Acanthosis nigricans: velvety darkened skin on the back of the neck, armpits or groin, and skin tags
- In women, irregular periods, acne, excess facial hair or difficulty conceiving (PCOS)
- Raised blood pressure, high triglycerides and low HDL on other tests
- Fatty liver on ultrasound or a mildly raised ALT
Low HOMA-IR
A low HOMA-IR, under 0.5 or so, almost always means a low fasting insulin in someone with a normal glucose, and in a lean or active person that is simply very good insulin sensitivity. Endurance athletes and people on low-carbohydrate or calorie-restricted diets routinely score 0.3 to 0.7. There is no value that is too low in itself.
The exception is when insulin is low because the pancreas cannot make enough. In early type 1 diabetes, latent autoimmune diabetes in adults (LADA), long-standing type 2 diabetes, chronic pancreatitis or after pancreatic surgery, a low insulin comes with a high fasting glucose. The formula multiplies the two, so the result can look normal or low even though something is seriously wrong. That is why HOMA-IR must never be read without looking at the glucose and, where there is doubt, a C-peptide.
Common causes
Good insulin sensitivity
Lean body composition, regular aerobic and resistance exercise and adequate sleep keep fasting insulin under 5 uIU/mL and HOMA-IR around 0.5 to 1.0. This is the expected result in healthy younger adults.
Low-carbohydrate or ketogenic eating, fasting or recent weight loss
Fasting insulin falls within days of cutting carbohydrate or calories, lowering the score; the effect is real but partly reflects what you ate in the preceding days rather than a permanent change.
Type 1 diabetes and LADA
Autoimmune destruction of beta cells leaves insulin low while glucose rises; the HOMA-IR may be 1 to 2 despite overt diabetes. Glucose, A1C, C-peptide and GAD antibodies, not HOMA-IR, make the diagnosis.
Long-standing type 2 diabetes with beta-cell exhaustion
After years of compensating, the pancreas's insulin output falls and HOMA-IR drops back toward normal as glucose climbs, a pattern that signals the need for insulin treatment rather than reassurance.
Chronic pancreatitis, cystic fibrosis or pancreatic surgery
Loss of pancreatic tissue reduces insulin production; glucose is high and insulin and C-peptide are low.
Laboratory and sampling issues
Insulin degrades if the sample sits unspun for hours, and hemolysed samples read low. A result that does not fit the clinical picture should be repeated.
Symptoms that can go with it
- None when the cause is good insulin sensitivity
- If insulin is low because the pancreas is failing: thirst, frequent urination, unintended weight loss, blurred vision or fatigue, with a high glucose
- Nausea, abdominal pain or rapid breathing with a very high glucose is diabetic ketoacidosis and is an emergency
Read it alongside
- Fasting insulin — the driver of the number; a fasting insulin above 10-15 uIU/mL is itself a marker of insulin resistance whatever the glucose.
- Fasting glucose — confirms the pancreas is still compensating (glucose under 100 mg/dL) or starting to fail (100-125 prediabetes, 126 or more diabetes).
- A1C — the 3-month average of blood sugar; a normal A1C with a high HOMA-IR is the classic early picture, well before prediabetes.
- Triglycerides and HDL cholesterol — a triglyceride-to-HDL ratio above 3 (in mg/dL) is a rough proxy for insulin resistance when insulin was not measured.
- ALT and GGT — a mild rise suggests fatty liver, the most common organ consequence of insulin resistance.
- C-peptide — distinguishes high insulin from the pancreas from a low-output pancreas when HOMA-IR is unexpectedly low with a high glucose.
- Uric acid — rises with insulin resistance because insulin reduces urate excretion by the kidney.
- SHBG — low sex hormone binding globulin is an independent marker of insulin resistance and is often ordered with HOMA-IR in PCOS.
What usually happens next
- If the result is 2 or higher, repeat fasting insulin and glucose in a few weeks after a strict 10 to 12 hour fast, and ask for triglycerides, HDL, A1C and ALT if they were not done, so the full metabolic picture is clear.
- Measure your waist and blood pressure; three or more of waist over 40/35 inches, triglycerides over 150, HDL under 40/50, blood pressure over 130/85 and glucose over 100 is metabolic syndrome and sharpens the priority of lifestyle change.
- If ALT or GGT is raised, or HOMA-IR is above 3 with obesity, ask about a liver ultrasound or FibroScan for fatty liver.
- Women with irregular periods, acne or hirsutism and a high HOMA-IR should be evaluated for PCOS (testosterone, SHBG, LH/FSH, ultrasound).
- Review medications that raise insulin resistance (steroids, antipsychotics, thiazides) with your prescriber; do not stop any of them on your own.
- Recheck after 3 to 6 months of changes to weight, activity and sleep; a fall of 30 percent or more is typical when they are sustained.
Diet, lifestyle and natural levers with evidence
What can move HOMA-IR once the cause is known. Nothing here replaces finding the cause.
Weight loss of 5 to 10 percent, especially abdominal fat
Strong evidenceIn the Diabetes Prevention Program, an average 7 percent weight loss with 150 minutes a week of activity cut progression to diabetes by 58 percent over about 3 years, and HOMA-IR fell in step with weight. Across trials, each kilogram lost lowers fasting insulin by roughly 3 to 5 percent, so a 10 kg loss commonly moves HOMA-IR from 3.5 to around 2.
Aerobic plus resistance exercise
Strong evidenceA meta-analysis of randomised trials in people with type 2 diabetes found exercise training lowered HOMA-IR by about 1.0 unit, with combined aerobic and resistance programs outperforming either alone. A single session improves insulin sensitivity for 24 to 48 hours, so the effect depends on consistency; 150 minutes a week of brisk activity plus two strength sessions is the dose most guidelines use.
Mediterranean or low-glycemic eating pattern
Moderate evidenceMeta-analyses of dietary trials show Mediterranean-style and low-glycemic-index diets lower HOMA-IR by about 0.5 to 1.0 compared with usual Western eating, with most of the benefit from replacing refined grains and sugary drinks with vegetables, legumes, nuts, olive oil, fish and whole grains. Low-carbohydrate diets produce similar or larger short-term falls in fasting insulin, mainly through weight and liver-fat loss.
Sleep of 7 to 8 hours and treatment of sleep apnea
Moderate evidenceExperimental sleep restriction to 4 to 5 hours a night reduces insulin sensitivity by 20 to 25 percent within a week in healthy adults, and extending sleep in habitually short sleepers improves it. In people with obstructive sleep apnea, meta-analyses of CPAP trials show modest improvements in HOMA-IR (around 0.4 to 0.6) with regular use.
Berberine
Moderate evidenceA meta-analysis of 27 randomised trials in type 2 diabetes found berberine (usually 500 mg two to three times a day for 2 to 3 months) lowered HOMA-IR by about 0.9 to 1.0 and A1C by about 0.7 percentage points, comparable to metformin in head-to-head trials. Trials are mostly small and from China, so the evidence tier is moderate rather than strong.
Can cause constipation or nausea, lowers glucose further with diabetes drugs, inhibits liver enzymes that clear many medications (including some statins and cyclosporine), and should not be used in pregnancy or breastfeeding or given to newborns.
Myo-inositol (particularly in PCOS)
Moderate evidenceMeta-analyses of randomised trials in women with PCOS found myo-inositol (2 g twice a day for 12 to 24 weeks) lowered HOMA-IR by about 1.0 and fasting insulin by 2 to 3 uIU/mL compared with placebo, with improvements in ovulation. Evidence in people without PCOS is thinner.
Mild nausea or loose stools at higher doses; limited data in pregnancy beyond gestational diabetes trials.
When to see a clinician promptly
- A fasting glucose above 250 mg/dL, or any glucose with thirst, frequent urination, vomiting, abdominal pain or rapid breathing: possible diabetic ketoacidosis or hyperglycemic crisis, needs same-day care.
- A high HOMA-IR together with a fasting glucose of 126 mg/dL or more or an A1C of 6.5 percent or more, which is diabetes and needs a confirmed diagnosis and a plan.
- A low HOMA-IR with a high glucose, unintended weight loss or ketones, which suggests the pancreas is failing (type 1, LADA or exhausted type 2) rather than insulin resistance.
- A HOMA-IR above 3 with raised ALT, so fatty liver can be assessed and staged.
- Women with a high HOMA-IR and irregular periods, hirsutism or infertility, for PCOS evaluation.
- A HOMA-IR that is rising despite weight loss and exercise, or above 5 with a normal weight, which raises the possibility of a hormonal or genetic cause.
Frequently asked questions
How do I calculate HOMA-IR?
Multiply your fasting insulin (in uIU/mL, the same as mIU/L) by your fasting glucose (in mg/dL) and divide by 405. For example, insulin 8 and glucose 95: 8 x 95 = 760, divided by 405 = 1.9. If your glucose is in mmol/L, divide the product by 22.5 instead. Both numbers must come from the same fasting sample. Online calculators do the same arithmetic; the HOMA2 calculator from the University of Oxford uses an updated model and gives lower values with different cut-offs.
What is a normal HOMA-IR?
About 1.0 is the textbook normal, most healthy lean adults fall between 0.5 and 1.9, and 2.0 to 2.9 is borderline. There is no single agreed upper limit: many US laboratories and clinicians use 2.0 or 2.5, most US research uses about 2.9 or 3.0, and the right cut-off varies with ethnicity, age and the insulin assay. A result of 1.5 is reassuring; 2.5 means insulin resistance is probably present and worth acting on; 3.5 or more is clear insulin resistance.
Is a HOMA-IR of 2.5 or 3 bad?
A HOMA-IR of 2.5 to 3 sits at the threshold most labs use for insulin resistance. It does not mean you have diabetes, and your glucose and A1C may be entirely normal, but it indicates your pancreas is working two to three times harder than it should and your risk of prediabetes, fatty liver and metabolic syndrome is raised. It is also the range that responds best to weight loss, exercise and sleep, often falling below 2 within 3 to 6 months.
Can I have insulin resistance with a normal glucose and A1C?
Yes, and that is the usual situation. The pancreas compensates for insulin resistance by making more insulin, which keeps glucose normal for years. Glucose and A1C only rise once that compensation starts to fail. A fasting insulin above 10 to 15 uIU/mL or a HOMA-IR above 2 to 3 with normal glucose is the earliest detectable stage, which is exactly why some clinicians measure it.
How fast can HOMA-IR go down?
Fasting insulin responds within days to a lower-calorie or lower-carbohydrate diet, and within one to two weeks to regular exercise, so a HOMA-IR can fall 20 to 30 percent in a month. Durable change tracks fat loss, particularly around the waist and in the liver; a 7 to 10 percent weight loss over 3 to 6 months typically lowers HOMA-IR by a third to a half. Because the number is noisy, judge progress on two or three measurements, not one.
Does a low HOMA-IR mean anything?
In a lean, active person a HOMA-IR of 0.3 to 0.8 just reflects excellent insulin sensitivity or a low-carbohydrate diet and needs nothing. The one situation to take seriously is a low HOMA-IR alongside a high fasting glucose (over 100 mg/dL), weight loss or thirst, because that pattern means the pancreas is producing too little insulin, as in type 1 diabetes, LADA or exhausted type 2 diabetes. A C-peptide and diabetes antibodies sort this out.
Does metformin or other medication change HOMA-IR?
Yes. Metformin lowers fasting insulin and HOMA-IR by roughly 20 to 30 percent, GLP-1 agonists and SGLT2 inhibitors by a similar or larger amount mainly through weight loss, and pioglitazone directly improves insulin sensitivity. In the other direction, steroids, some antipsychotics, thiazides and beta-blockers raise it. Tell whoever interprets the test what you take; a result on medication reflects treated, not untreated, insulin resistance.
Why do doctors not routinely order HOMA-IR?
Because fasting insulin assays are not standardised between labs, a single value varies by 20 to 30 percent day to day, there is no universally agreed cut-off, and it rarely changes management: the advice for a HOMA-IR of 3 (weight, activity, sleep, diet) is the same as for a large waist with high triglycerides and low HDL. Guidelines therefore recommend glucose and A1C for diagnosing prediabetes and diabetes. HOMA-IR is still a useful early-warning and tracking number, particularly in PCOS, fatty liver and people with a strong family history of diabetes.
References
- Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia (1985)View source
- Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care (2004)View source
- Gayoso-Diz P, Otero-Gonzalez A, Rodriguez-Alvarez MX, et al.. Insulin resistance (HOMA-IR) cut-off values and the metabolic syndrome in a general adult population: effect of gender and age (EPIRCE cross-sectional study). BMC Endocrine Disorders (2013)View source
- Qu HQ, Li Q, Rentfro AR, Fisher-Hoch SP, McCormick JB. Definition of insulin resistance using the homeostasis model assessment (HOMA-IR) in a population of Americans of Mexican descent. PLoS ONE (2011)
- Knowler WC, Barrett-Connor E, Fowler SE, et al.; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine (2002)View source
- Sampath Kumar A, Maiya AG, Shastry BA, et al.. Exercise and insulin resistance in type 2 diabetes mellitus: a systematic review and meta-analysis. Annals of Physical and Rehabilitation Medicine (2019)
- Lan J, Zhao Y, Dong F, et al.. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. Journal of Ethnopharmacology (2015)
- Unfer V, Facchinetti F, Orru B, Giordani B, Nestler J. Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials. Endocrine Connections (2017)
- Insulin resistance and prediabetes. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (2018)View source
- Insulin in blood. MedlinePlus, US National Library of Medicine (2022)View source
- American Diabetes Association Professional Practice Committee. Diagnosis and classification of diabetes: Standards of Care in Diabetes - 2025. Diabetes Care (2025)
- Van Cauter E, Spiegel K, Tasali E, Leproult R. Impact of sleep and sleep loss on glucose homeostasis and appetite regulation. Sleep Medicine (2008)
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