Insulin
The hormone that regulates blood sugar — often elevated long before fasting glucose changes.
What is it
Fasting insulin measures circulating insulin after an overnight fast. It is one of the earliest markers to change when insulin resistance begins to develop.
Why it's measured
Elevated fasting insulin has been associated with insulin resistance and metabolic syndrome features in research literature, often years before fasting glucose rises.
Reference range
Standard laboratory reference
< 10 μIU/mL
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
Where does your number land?
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Drag to your own Fasting Insulin result.
Educational only, not a diagnosis. Ranges vary by laboratory. See which panel includes Fasting Insulin.
What results may indicate
Elevated
Has been associated with insulin resistance and elevated cardiometabolic risk in published research.
Lower
Is generally considered favorable in research on metabolic health.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Not routinely included in standard physicals — often ordered when investigating metabolic dysfunction.
Related markers
Common questions
Fasting insulin measures circulating insulin after an overnight fast. It is one of the earliest markers to change when insulin resistance begins to develop.
It's one of the markers used to build a fuller picture of your health. On its own it tells you very little, so it's most informative when reviewed alongside related markers.
It's measured from a standard blood draw at Quest or LabCorp. Fasting Insulin is one of the markers included in the OPTML Apex Panel, where your results are read across systems and reviewed by a U.S.-licensed physician.
Reference ranges vary by laboratory, and a single value rarely tells the whole story. Review your result with a physician in the context of your other markers, symptoms, and history.
Fasting Insulin is one signal among many. Answer a few quick questions and we’ll point you to the panel that fits.
Related symptoms
A symptom is a signal, not a diagnosis. These guides explain what the evidence shows and the blood markers, including this one, that help find the cause.
Fasting insulin is one of the markers most responsive to training. Resistance work improves how sensitive your tissues are to insulin, so the same glucose control needs less insulin. It often moves before fasting glucose does, which makes it a useful early signal. If you want a structured place to start, the training library lists every programme we publish by days per week and equipment.
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Find the right panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.
OPTML offers compounded semaglutide and tirzepatide, prescribed and overseen by U.S.-licensed physicians. Compounded drug products are not approved or evaluated for safety, effectiveness, or quality by the FDA. OPTML is not associated with, endorsed by, or affiliated with the manufacturers of FDA-approved branded weight-loss medications, and does not sell or supply those branded products. Anyone interested in an FDA-approved branded medication should consult a licensed healthcare provider or pharmacist. Individual results vary; no specific result is promised, and weight management requires ongoing medical guidance.
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