TirzTom said:

HbA1c reflects roughly three months of average glycaemia weighted toward the most recent weeks, which is why repeating it at six weeks tells you very…

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 → 13 → 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.

One thing that is still open after Dr.LipidDallas’s answer:

Was that from a primary source or from a summary of one?

DataDave 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…

PCOS success story with glycaemic control: as someone with polycystic ovary syndrome, this medication has been transformative beyond weight loss.

After 9 months: periods became regular for the first time in ever, testosterone levels normalized, acne cleared significantly, and — unexpectedly — my hormonal symptoms have almost completely resolved.

GLP-1 agonists address the insulin resistance at the root of PCOS. For PCOS patients, this isn't "just" a weight loss drug — it's treating our underlying metabolic dysfunction.

DataDave 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 39% 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.

Dr.KarenChen said:

PCOS success story with glycaemic control: as someone with polycystic ovary syndrome, this medication has been transformative beyond weight loss.

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 = 5.5 (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.