JennaRN 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…

Glycemic variability as the key metric for glycaemic control success: my coefficient of variation (CV) on CGM dropped from 42% to 20%. Target is <36%, with <30% being ideal.

Why this matters more than average glucose: large glucose swings cause oxidative stress, endothelial damage, and promote advanced glycation end-products (AGEs). A flat glucose line at 95 mg/dL is metabolically healthier than oscillating between 60 and 160, even if the average is the same.

WendyG_ATL 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.

My labs after 9 months on glycaemic control: A1C 5.9%, fasting glucose 89 mg/dL, fasting insulin 4 uIU/mL. My endo says these are "textbook perfect."

For context, my baseline A1C was 7.3% and fasting glucose was 134 mg/dL. The improvement has been dramatic and consistent.

PurityPaulOR said:

Glycemic variability as the key metric for glycaemic control success: my coefficient of variation (CV) on CGM dropped from 42% to 20%.

Complete metabolic panel trending on glycaemic control — sharing because comprehensive data helps everyone:

The insulin resistance improvement (HOMA-IR) is what my endo focuses on most. Going from 5.5 to near 1.0 is a metabolic transformation.

One thing that is still open after kim_atl_prep’s answer:

How would you tell the difference between that and the alternative explanation?

hans_munich said:

Complete metabolic panel trending on glycaemic control — sharing because comprehensive data helps everyone: Test Baseline Month 3 Month 6 Month 12…

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 = 5.0 (insulin resistant) → Current = 1.0 (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.