Fasting insulin
Insulin is a hormone from the pancreas that opens the door for cells to take up glucose from the blood. The fasting level shows how much insulin the body needs to maintain normal sugar — an indirect indicator of insulin sensitivity.
| Rating | Range | What it means |
|---|---|---|
| Good | below 8 mIU/L | Your pancreas is working with ease — good insulin sensitivity. |
| Worth improving | 8 – 12 mIU/L | Slightly elevated — an early sign of insulin resistance. |
| Talk to a doctor | 12 mIU/L and above | Elevated — likely insulin resistance; take action + seek advice. |
Why it matters
There is no diagnostic threshold; it is used to assess insulin resistance (e.g. HOMA-IR). A higher fasting level suggests resistance.
If it’s low
Low insulin is usually favorable in healthy people (good sensitivity); a very low value with high blood sugar suggests a deficiency (type 1 diabetes).
If it’s high
Elevated insulin means your body has to secrete more of the hormone for the same effect — the beginning of insulin resistance. It is accompanied by excess weight, high triglycerides and low HDL.
What to do
High insulin is an opportunity: movement, loss of visceral fat and fewer fast carbohydrates often improve sensitivity within weeks.
When to see a doctor
High insulin with high blood sugar/HbA1c or metabolic syndrome — a consultation
Read together with
Fasting glucose · HbA1c · Triglycerides · HDL cholesterol
Part of the guide: Blood sugar & insulin →
Articles about this marker
- Blood biomarkers of metabolic health: what to measure and whyMetabolic health
- Blood sugar and HbA1c: what they mean and how to calm themMarker explained
- How to steady your blood sugar: an action planHow to improve
- Prediabetes: what HbA1c 5.7–6.4 means and how to reverse itMetabolism
- Unexplained weight gain: what to really check in your bloodSymptom → test
This content is for information only and is not a substitute for medical advice. Talk to your doctor about your results.
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