Insulin resistance is estimated to affect somewhere between 35% and 80% of people with PCOS — and a standard "your bloods are normal" panel often does not test for it at all.
A routine panel usually checks fasting glucose. Insulin resistance means your body is working harder to keep that glucose normal — so for years the glucose can look fine while the insulin doing the work is climbing.
By the time fasting glucose is abnormal, the picture has already moved on. To see insulin resistance itself, you have to measure insulin.
All of these need an 8 to 12 hour fast. Book a morning slot and do not have breakfast first — a non-fasting fasting insulin is a wasted appointment.
Reference ranges vary between labs, and your doctor interprets these in the context of everything else about you. As a rough orientation:
Treat these as conversation-starters with your doctor, not as a self-diagnosis. A single number slightly over a threshold is not a verdict.
Acanthosis nigricans is a velvety darkening of the skin, usually at the back and sides of the neck, in the armpits or in the groin. It is frequently mistaken for dirt that will not scrub off. It is associated with insulin resistance, and it is worth showing your doctor rather than covering up.
Its absence does not rule anything out. Plenty of people with insulin resistance have no visible sign at all.
Insulin resistance is part of why PCOS behaves the way it does — it is bound up with the higher androgen levels that drive irregular cycles, acne and unwanted hair. It also matters for long-term health: the CDC lists PCOS as a risk factor for type 2 diabetes.
Knowing where you stand changes what is worth your effort. It is the difference between guessing at a diet and having a reason for one.
Bloods are a snapshot every six or twelve months. What happens between them is where you actually live.
Logging what you eat alongside how you feel is how you find out which foods reliably precede a bad day for you — which is not the same as the list on a generic PCOS diet page. PCOS Ai does this correlation on your phone and can hold your lab results next to it, so a follow-up appointment starts with evidence instead of recollection.
If you are preparing for that appointment, our endocrinologist appointment guide covers how to make a short slot count.
Fasting insulin is sometimes declined as not routinely indicated, and that is a legitimate clinical position rather than a brush-off. Reasonable things to ask: what would need to be true for it to be worth testing, and whether HbA1c or an oral glucose tolerance test would be a better fit for your situation. Both are useful answers.
General wellness information, not medical or dietetic advice. Nothing here diagnoses, treats or cures PCOS. Nutrition figures are per-serving estimates. Check with your doctor or a registered dietitian before making significant changes — especially if you are pregnant, breastfeeding, diabetic or managing a food allergy.