Fasting Serum Insulin— Normal Range & What Your Result Means

Normal Fasting Serum Insulin range (Fasting Insulin, μIU/mL)

  • Adults2–25 μIU/mL

Ranges are typical adult values and vary between labs. Use the range on your own report.

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What is Fasting Serum Insulin (Fasting Insulin)?

Fasting Serum Insulin is measured as part of a diabetes & blood sugar panel. Your fasting insulin is in a healthy range.

What does a high Fasting Serum Insulin mean?

Your fasting insulin is elevated, which often signals insulin resistance — the body producing extra insulin to keep glucose normal. This is common before type 2 diabetes and is interpreted alongside glucose (and HOMA-IR).

What does a low Fasting Serum Insulin mean?

Your fasting insulin is low. In a non-diabetic this is usually not a concern; in diabetes it can reflect reduced insulin production.

Understand your whole report, not just one number

A single value rarely tells the full story — Fasting Serum Insulin is best read alongside the rest of your panel. Paste your values or upload your report and get a plain-English explanation of every marker, with the important results flagged.

Fasting Serum Insulin: frequently asked questions

What is a normal Fasting Serum Insulin level?

A normal Fasting Serum Insulin (Fasting Insulin) level is 2–25 μIU/mL for adults. Reference ranges vary slightly between laboratories, so always compare against the range printed on your own report.

What does a high Fasting Serum Insulin mean?

Your fasting insulin is elevated, which often signals insulin resistance — the body producing extra insulin to keep glucose normal. This is common before type 2 diabetes and is interpreted alongside glucose (and HOMA-IR).

What does a low Fasting Serum Insulin mean?

Your fasting insulin is low. In a non-diabetic this is usually not a concern; in diabetes it can reflect reduced insulin production.

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