Test for insulin resistance with blood tests: fasting glucose and fasting insulin (used to calculate HOMA‑IR), HbA1c, and an oral glucose tolerance test (OGTT)—sometimes with insulin measurements. Lipids and C‑peptide help assess metabolic risk. The gold‑standard euglycemic hyperinsulinemic clamp is reserved for research. Discuss results and next steps with your clinician.

Insulin resistance may be suspected with abdominal obesity, fatigue, skin darkening (acanthosis nigricans), irregular periods or PCOS, high blood pressure, and abnormal lipid levels. Confirm with blood tests: fasting glucose and insulin, HOMA‑IR calculation, HbA1c, and an oral glucose tolerance test. Your clinician may also check triglycerides and HDL. Early detection needs medical evaluation and lifestyle changes.

The HbA1c test measures average blood glucose over the past 2–3 months by detecting glycosylated hemoglobin. It’s used to diagnose and monitor diabetes and prediabetes (normal <5.7%, prediabetes 5.7–6.4%, diabetes ≥6.5%). It doesn’t directly measure insulin resistance, but an elevated HbA1c often reflects chronic hyperglycaemia that can result from or indicate insulin resistance; other tests assess sensitivity directly.

Insulin resistance is commonly assessed with HOMA‑IR. A normal HOMA‑IR is generally <1.0. Values of about 1.0–1.9 suggest borderline/early insulin resistance; 2.0–2.9 indicate moderate insulin resistance; and ≥3.0 is considered significant insulin resistance. Fasting insulin typically falls roughly between 2–20 μIU/mL, but cutoffs vary by lab and population. Discuss results with your clinician for personalised interpretation.

Symptoms of high insulin resistance include increased hunger, fatigue, difficulty losing weight and central (abdominal) weight gain, dark velvety skin patches (acanthosis nigricans) or skin tags. Women may have irregular periods and excess facial or body hair (PCOS features). It often causes high blood sugar signs—frequent urination and excessive thirst—and is commonly linked with high blood pressure and abnormal lipids.

The best test depends on context: the hyperinsulinemic-euglycemic clamp is the research gold standard for quantifying insulin resistance but is impractical clinically. For routine practice, fasting glucose and insulin used to calculate HOMA‑IR is the most practical and widely used screening test. An oral glucose tolerance test (OGTT) can provide additional information on post-load insulin response when needed.