Metabolic panel
Fasting insulin
Measured in µIU/mL
What it measures
Circulating insulin after an overnight fast.
Why it is tracked
Insulin resistance develops well before glucose becomes abnormal. Fasting insulin can reveal a metabolic problem years earlier than glucose or HbA1c would, which is why it appears in longevity panels more often than in routine care.
What a provider considers
- Often normal-glucose but high-insulin in early insulin resistance
- Used to calculate HOMA-IR alongside fasting glucose
- Affected by recent carbohydrate intake
Reference ranges vary between laboratories and a single result rarely means much on its own. Interpretation depends on your symptoms, your other markers and the trend over time — which is what your provider reviews.