Why fasting glucose isn't enough
Glucose only drifts up once the pancreas can no longer compensate. By that point, insulin has often been twice or three times optimal for years, quietly damaging cardiovascular and brain tissue. Fasting insulin catches the problem early; HbA1c adds 3-month average context; HOMA-IR (calculated from glucose × insulin) quantifies the relationship.
What to test
Fasting insulin (12-hour fast), fasting glucose, HbA1c, the triglyceride/HDL ratio (a simple metabolic-health proxy), SHBG (insulin suppresses it), and — in women under 40 with cycle issues — testosterone and DHEA-S to rule in or out PCOS.
Optimal vs 'normal' ranges
Lab 'normal' for fasting insulin often stretches to 25 mIU/L. Most metabolic-health doctors aim for under 7. HbA1c 'normal' is under 5.7% but optimal is closer to 5.0–5.3. Low SHBG (under ~40 nmol/L in cycling women) is an early insulin red flag.
What to do
Protein-forward meals, fewer snacks, daily walking (especially post-meal), strength training 2–3x weekly, prioritise sleep, treat any thyroid issue in parallel. Re-test fasting insulin and HbA1c at 3–4 months — both move meaningfully with consistent work. Inositol, berberine and (where indicated) metformin can support, but they don't replace the lifestyle base.
The metabolic engine behind PCOS, perimenopausal weight gain, brain fog and stubborn cravings.
Frequently asked
Fasting insulin combined with HbA1c, ideally with a HOMA-IR calculation. Fasting glucose alone misses years of early insulin dysfunction.
Yes — that's the early stage. Insulin climbs for years before fasting glucose moves. Catching it then makes reversal much easier.
Lab 'normal' often goes up to 25 mIU/L but metabolic-health doctors aim for under 7 fasting.
Yes — especially when caught early. Most women see meaningful change in fasting insulin within 12 weeks of consistent diet, strength training and sleep work.
It's the dominant driver in the most common PCOS subtype. Treating insulin often restores ovulation and lifts androgens without medication.
Myo- + d-chiro-inositol (40:1) improves insulin sensitivity in women in trials, particularly those with PCOS. It's cheap, low-risk and a reasonable adjunct to lifestyle work.