A1C went from 7.4 to 5.6 over nine months and my prescriber was more interested in the fasting insulin, which I did not expect.
What I am after is why A1C lags the way it does, and what to look at in the meantime if you want to know sooner.
Practical detail welcome, however dull — the duller the better.
steph_laguna said:A1C went from 7.4 to 5.6 over nine months and my prescriber was more interested in the fasting insulin, which I did not expect.
Fasting insulin is the lab my functional medicine doctor cares about most for glycaemic control: it's a much earlier marker of metabolic dysfunction than glucose or A1C.
My fasting insulin: 23 → 15 → 7 uIU/mL over 9 months. Target is <7. By the time your fasting glucose is elevated, your insulin has been elevated for YEARS trying to compensate.
Ask your doctor to include fasting insulin in your bloodwork panel. It's cheap (~$20) and incredibly informative.
Dr.NateNeph said:Fasting insulin is the lab my functional medicine doctor cares about most for glycaemic control: it's a much earlier marker of metabolic dysfunction…
Patient selection optimization for glycaemic control: emerging predictive biomarkers for GLP-1 agonist response include:
| Biomarker | Association | Evidence Level |
|---|---|---|
| Baseline BMI | Higher BMI → greater absolute weight loss | Strong |
| Fasting insulin | Higher insulin → better response | Moderate |
| GLP1R gene variants | rs6923761 → variable response | Preliminary |
| Baseline hsCRP | Higher CRP → greater CV benefit | Moderate |
| Early weight loss (4 wk) | ≥3% at 4 wks → strong predictor of ≥10% at 68 wks | Strong |
The 4-week early responder criterion is the most clinically actionable: if you haven't lost ≥3% by week 4 at a therapeutic dose, discuss optimization strategies with your provider.
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Shop Reference Standardssteph_laguna said:A1C went from 7.4 to 5.6 over nine months and my prescriber was more interested in the fasting insulin, which I did not expect.
Same experience, arrived at from the opposite direction.
Clinical perspective, offered as context rather than as advice.
Insulin sensitivity test (HOMA-IR) on glycaemic control — arguably the most important metabolic marker most people aren't tracking:
HOMA-IR = (fasting insulin × fasting glucose) ÷ 405
My numbers: Baseline HOMA-IR = 4.9 (insulin resistant) → Current = 1.5 (insulin sensitive)
Anything above 2.0 indicates insulin resistance. The goal is below 1.5. GLP-1 agonists address the root metabolic dysfunction, not just the symptoms. This is why they work so much better than calorie restriction alone.