Nobody explained this to me for years — and honestly, it's one of the things I wish every woman knew before her next blood draw.
Your doctor orders blood work. Fasting glucose: normal. A1C: normal. Everything looks fine on paper. But there's a test most standard panels don't include that tells a completely different story. It's called fasting insulin — and it might be the most important number you've never been given.
Here's the thing about glucose
Think of your fasting glucose as the score at the end of the game. Fasting insulin is how hard your body had to work to achieve that score.
You can have a perfectly normal fasting glucose of 88 — and a fasting insulin of 22, which means your pancreas is working overtime just to keep that number in range. The score looks great. The effort behind it tells another story entirely.
By the time glucose starts climbing, the problem has often been building for years. Fasting insulin is the earlier signal.
So why isn't it on your standard panel?
This is the part that frustrated me when I learned it.
Standard metabolic panels were designed around glucose because glucose is the number that changes last. By the time glucose is elevated, the diagnosis is clear and the path forward is straightforward.
Fasting insulin can catch changes in insulin sensitivity years before glucose starts to climb. But earlier detection means more ambiguity and more follow-up — and the current system isn't really built for that.
The test itself costs around $35 if you order it directly through labs like Ulta Lab Tests or Walk-In Lab. It requires fasting — nothing but water for at least 8 hours before the draw.
What the numbers mean
Standard lab ranges flag fasting insulin above 25 uIU/mL as high. But functional medicine practitioners often work with a much tighter range:
| 2–5 uIU/mL | Optimal |
| 6–9 uIU/mL | Acceptable, worth monitoring |
| 10–16 uIU/mL | Elevated, worth a conversation |
| 17+ uIU/mL | Above functional optimal range, worth discussing with your doctor |
These are reference ranges, not diagnoses. One number never tells the whole story — your symptoms, your history, your full picture all matter.
The number that unlocks even more: HOMA-IR
When you have both your fasting glucose and your fasting insulin, you can calculate something called HOMA-IR — a research-validated estimate of insulin sensitivity.
(fasting glucose × fasting insulin) ÷ 405
A HOMA-IR below 1.0 is considered optimal. Above 3.0 is associated with reduced insulin sensitivity in research literature.
ThriveIQ calculates your estimated HOMA-IR automatically when you've logged both values — and reminds you when fasting insulin is missing so you know exactly what to ask for at your next appointment.
What I'd ask at my next appointment
- Can we add fasting insulin to my next blood draw?
- Can we calculate my HOMA-IR together?
- What does my fasting insulin trend mean in the context of my other markers?
Your glucose being normal is good news. It's just not the whole story. Fasting insulin is the chapter most standard panels skip entirely.
If you're ready to start tracking your full picture, ThriveIQ was built for exactly this.
Start tracking at thriveiq.app