Fasting Insulin: normal range and what it means
How hard your pancreas works to keep glucose stable — an early insulin-resistance marker.
Normal range
Adult reference range.
- Optimal< 5 µIU/mL
- Elevated5 – 10 µIU/mL
- High≥ 10 µIU/mL
What it measures
The level of insulin circulating while fasting. High values mean your body needs lots of insulin to manage blood sugar — an early warning long before glucose rises.
What moves it
Body composition, refined-carb intake, activity, sleep and stress.
How to bring it into range
Fat loss, Zone-2 cardio, strength training and reducing refined carbs.
How fast it responds
Weeks to months.
Also reported as: insulin fasting
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Common questions
- What is a normal Fasting Insulin level?
- Optimal: < 5 µIU/mL. Adult reference range.
- What does a high Fasting Insulin mean?
- A value above the reference band means Fasting Insulin is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my Fasting Insulin?
- Fat loss, Zone-2 cardio, strength training and reducing refined carbs.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.