Fasting insulin is the earliest measurable signal of insulin resistance — often elevated for years before blood glucose rises above normal. Most people have never had it tested.
The Stack Analyzer maps your goals and current data to the right measurement path, protocol, and stack — in order.
When cells begin to resist insulin's signal, the pancreas compensates by producing more insulin to maintain normal blood glucose. This compensation can succeed for years — glucose stays "normal" while insulin climbs steadily higher. By the time glucose rises, insulin resistance is already well-established.[1]
Fasting insulin captures this compensatory phase early. It is one of the most powerful early-warning metabolic markers available, and it is absent from nearly every standard blood panel.
Most US laboratory reference ranges flag fasting insulin as normal up to 24–25 µIU/mL. Research consistently shows that optimal fasting insulin is under 7 µIU/mL and that values above 10 µIU/mL are associated with meaningful metabolic risk — even when glucose is completely normal.[2]
µIU/mL (micro-international units per milliliter)
Under 7 µIU/mL
Above 10 µIU/mL (warrants attention even with normal glucose)
Fasting — 8–12 hours, no food or caloric drinks
Every 90 days if above optimal during active intervention
| Fasting Insulin | Interpretation |
|---|---|
| Under 5 µIU/mL | Optimal insulin sensitivity |
| 5–7 µIU/mL | Good — within optimal range |
| 7–10 µIU/mL | Borderline — early compensation signal |
| 10–15 µIU/mL | Elevated — likely early insulin resistance |
| Over 15 µIU/mL | High — significant insulin resistance, clinical conversation warranted |
Reference ranges vary by lab, age, sex, medication status, and clinical context. Use these as discussion prompts with your clinician — not as diagnosis.
Fasting insulin is not in standard panels — request it specifically. Quest and Function Health both include it.
See: Interpreting high fasting insulin →
For cardiometabolic risk, the highest-value home measurements are blood pressure, glucose response, and rhythm awareness.
The Stack Analyzer uses your measurements to build a personalized protocol, supplement stack, and 30-day plan.