MikeKY_noInsulin 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.

Glycemic variability as the key metric for glycaemic control success: my coefficient of variation (CV) on CGM dropped from 40% to 21%. 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.

DataDave said:

Glycemic variability as the key metric for glycaemic control success: my coefficient of variation (CV) on CGM dropped from 40% to 21%.

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: 28 → 14 → 6 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.

MikeKY_noInsulin 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.

Can confirm. Same sequence, different timescale. The detail I would add is minor and it is already implied above.

Adding the clinical framing, because it changes how the question reads.

My labs after 12 months on glycaemic control: A1C 5.6%, fasting glucose 86 mg/dL, fasting insulin 7 uIU/mL. My endo says these are "textbook perfect."

For context, my baseline A1C was 6.7% and fasting glucose was 131 mg/dL. The improvement has been dramatic and consistent.