Fasting insulin
Shows how hard your body is working to keep blood sugar normal - often flagging insulin resistance years before glucose or HbA1c rise.
TypeBlood test
HowStandard blood draw after an overnight fast.
How oftenBaseline if you have metabolic risk; repeat to track change.
BeforeFast 8–12 hours. Water is fine.
WhoPeople with excess weight around the waist, PCOS, high triglycerides, fatty liver or family history of diabetes.
Why normal blood sugar can hide a problem
When cells stop responding well to insulin, the pancreas simply makes more. Blood sugar stays normal - but insulin climbs. That can go on quietly for years before glucose finally rises and diabetes is diagnosed.
Stage 1
“My glucose is normal — am I fine?”
Insulin rises to compensate. Glucose and HbA1c still look normal. Fasting insulin can catch this.
Earliest signal
Stage 2
“My HbA1c is creeping up.”
The pancreas can’t fully keep up. Glucose starts rising into the prediabetes range.
Prediabetes
Why it matters
“What does it actually do?”
High insulin is linked to belly fat, high triglycerides, fatty liver, high blood pressure and heart risk.
Reversible early
If your insulin is high
This is the stage where lifestyle changes work best.
01
Build muscle
Strength training makes muscle soak up glucose with less insulin.
02
Move after meals
A 10–15 minute walk blunts the glucose and insulin spike.
03
Sleep and stress
Short sleep alone raises insulin resistance.
04
Retest
Recheck in 3–6 months to see change.
Is it right for you?
Worth considering if…
- You carry weight around your waist, even if your weight is “normal”.
- You have high triglycerides, fatty liver, PCOS or high blood pressure.
- Type 2 diabetes runs in your family.
- Your HbA1c is at the high end of normal.
How it’s measured
Fasting insulin
A single morning blood value.
HOMA-IR
Calculated from fasting insulin and glucose - a simple insulin-resistance score.
Insulin with a glucose tolerance test
Measures insulin response over 2 hours - more detail, rarely needed.
The full picture
What is it?
A test of how much insulin is in your blood after an overnight fast.
What type of test is it?
A blood biomarker.
What does it measure?
Insulin concentration (µIU/mL). Combined with glucose, it gives HOMA-IR.
Why might someone consider it?
It can reveal insulin resistance long before glucose or HbA1c change - when it’s most reversible.
Who is it most relevant for?
People with metabolic risk factors or a family history of type 2 diabetes.
How is it performed?
A morning blood draw after fasting.
How often might it be considered?
Once as a baseline, then every 6–12 months if you’re working on it.
What can the result help you understand?
Whether your body needs more insulin than it should to keep glucose normal.
What are its limitations?
No standard reference range, results vary between labs, and it isn’t part of routine screening guidelines.
What should it be viewed with?
Fasting glucose, HbA1c, triglycerides and HDL, waist size, liver enzymes and blood pressure.
Where to get it
Through your provider
The simplest route - often covered when there’s a clear reason.
Lab services
e.g. Quest Diagnostics, Labcorp.
Direct-to-consumer panels
e.g. Function Health, InsideTracker.
Names are examples only, not endorsements. Your provider can often order the same test - and help interpret it.
Connected to
Questions to ask your provider
- Could I have early insulin resistance even with normal HbA1c?
- Should we calculate my HOMA-IR?
- What’s the most effective change for me?
Ziva Health
One test is a snapshot. Ziva shows the whole story.
Ziva brings your lab results, wearables and daily readings together - and Isabella tells you what’s changing and what to ask your provider next.
Refer Ziva to my provider / care team
Is your provider not on Ziva yet? Send them a link in under a minute - once they join, they’ll see your Fasting insulin result alongside your other trends and get alerts directly.
Refer my providerAlready seeing your provider?
Bring your Ziva 30-day report to your next appointment - your Fasting insulin result and daily trends in one view, so the conversation starts with the full picture.
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Being listed doesn’t mean everyone needs this test. Educational only — not medical advice. Results should be interpreted with a qualified clinician. ← Back to Know What to Test