Fasting Insulin
A measure of how much insulin your body needs at rest to keep blood sugar steady.
This is educational information, not a diagnosis. Only a doctor reviewing your full report and history can properly interpret your result.
What It Is
Fasting insulin measures the level of insulin circulating in your blood after an overnight fast, when blood sugar is not actively being pushed up by a recent meal.
Why It Matters
Insulin resistance often shows up as rising fasting insulin years before fasting glucose or HbA1c move out of range, which makes this marker useful for catching metabolic changes earlier.
Typical Reference Range
There's less international consensus on a single reference range for fasting insulin than for glucose, and labs vary in how they report it — it's generally interpreted alongside fasting glucose rather than as a standalone number.
What Can Affect Your Results
- Recent food intake (testing requires a genuine fast)
- Body weight and visceral fat
- PCOS and other hormonal conditions
- Physical activity levels
- Sleep quality and chronic stress
When It's Typically Checked
Fasting insulin isn't part of every routine panel, but is often added when insulin resistance, PCOS, or unexplained weight gain is being investigated.
Related Tests
Medical Disclaimer
This page is provided for general educational purposes only and does not diagnose, treat, or interpret your individual results. Reference ranges vary between laboratories and testing methods, and a result outside a ‘typical’ range does not necessarily indicate a health problem, just as a result inside it doesn’t rule one out. Only a qualified physician reviewing your complete health picture can properly interpret your lab results — please discuss your reports with Dr Naturals or your treating doctor rather than relying on this page alone.