Your Doctor Is Using the Wrong Test for PCOS Insulin Resistance
"I had normal blood glucose for 7 years, I had INSULIN RESISTANCE the whole time"
THE IR FILES · PART 1 OF 3
By Dr. Herman Weiss, MD, MBA, FACOG — Board-Certified OB/GYN · 25 Years Clinical Practice
hweissmd · The Metabolic Fix · Free Article · May 2026
She sat across from me in the exam room, 34 years old, exhausted, frustrated, and completely convinced she was losing her mind.
She’d been told for eight years that everything looked “fine.” Her blood sugar was normal. Her A1c was normal. Her thyroid was fine. And yet she couldn’t lose weight no matter what she did, her periods were a disaster, and she felt like she was fighting her own body every single day.
I ran one test her previous physicians hadn’t ordered.
Her fasting insulin was 34 μIU/mL. Her HOMA-IR — a measure of insulin resistance — was 7.8. For context, we start getting concerned above 2.5. She had been metabolically dysregulated for almost a decade. And not one physician had caught it, because not one physician had run the right test.
This is not a rare story in my practice. It is an almost daily one.
The test your OB/GYN almost certainly didn’t order
When a woman comes in with suspected PCOS, the standard metabolic workup most physicians run looks something like this: fasting glucose, HbA1c, maybe a lipid panel. These are useful tests. They’re just not the right tests for catching insulin resistance early in a young woman with PCOS.
Here’s the problem. Fasting glucose and HbA1c are markers of glucose dysregulation — they tell you what your blood sugar is doing. But insulin resistance, the metabolic engine driving most PCOS, is a disorder of insulin — not glucose. And insulin can be dangerously elevated for years before blood sugar ever moves out of the normal range. [1]
By the time your fasting glucose is elevated, you have often already spent years — sometimes a decade — in a state of compensatory hyperinsulinemia. Your pancreas has been working overtime, pumping out excess insulin to keep blood sugar in check, and the entire time, your ovaries have been responding to that insulin by overproducing androgens. Which means irregular periods. Which means acne. Which means the weight that won’t move regardless of what you eat.
The glucose test is measuring the aftermath. It’s not measuring the cause.
What the research says
A 2025 review in Reproductive and Developmental Medicine confirmed that insulin resistance is the predominant metabolic abnormality in PCOS, present in 60–80% of patients — and critically, that IR exists across all PCOS phenotypes, including lean women with normal BMI. [2] The glucose-centric approach to diagnosis misses most of them.
What HOMA-IR actually measures — and why it changes everything
HOMA-IR stands for Homeostatic Model Assessment of Insulin Resistance. It sounds complicated. The calculation is not.
You take a fasting glucose result (in mmol/L) and a fasting insulin result (in μIU/mL), multiply them together, and divide by 22.5. The number you get tells you how hard your body is working to manage its own insulin — and how well it’s succeeding. [3]
In clinical practice, I use these general thresholds:
Below 1.5 — Optimal insulin sensitivity
1.5 to 2.5 — Normal range, monitor over time
2.5 to 3.5 — Early insulin resistance, act now
Above 3.5 — Significant insulin resistance, metabolic intervention needed
The woman I described at the opening had a HOMA-IR of 7.8. That is not borderline. That is a metabolic emergency that had been sitting undetected for almost a decade because everyone was looking at her blood sugar and calling it normal.
“We’ve been measuring the wrong thing in women for 30 years. That’s not a gap in the science — it’s a gap in the standard of care. And it’s correctable.”
Why PCOS insulin resistance is particularly insidious
Insulin resistance in PCOS isn’t just a metabolic inconvenience. It is the engine of the condition. Here is the cycle, as simply as I can put it: excess insulin signals the ovarian theca cells to overproduce androgens. Those androgens disrupt follicular development, prevent normal ovulation, and drive the irregular cycles that bring most women to the clinic. Meanwhile, the insulin-androgen environment promotes visceral fat accumulation, which worsens insulin resistance further, which produces more androgens. [4]
Round and round it goes. And the longer it runs unchecked, the harder it is to interrupt.
This matters enormously for what comes next in a woman’s life. More than half of women with PCOS will develop type 2 diabetes by age 40. [5] The metabolic burden compounds as estrogen levels decline in perimenopause — a transition that tends to accelerate insulin resistance further and amplify cardiovascular risk. The women who enter perimenopause with unaddressed insulin resistance are at significantly higher risk for adverse outcomes. [6]
This is not a conversation we can defer. The window matters.
The lean PCOS reality
One of the most important points I want to make: insulin resistance is not a condition that only affects overweight women. Approximately 30% of PCOS cases occur in women with normal BMI. Many of these women are told they “don’t look like” they have PCOS or that their weight isn’t a problem — and their metabolic dysfunction goes completely unmeasured. HOMA-IR is the test that finds them.
What’s actually happening in your ovaries right now
I want to make this concrete, because I think most women with PCOS have been given a diagnosis without an explanation. So let me give you the explanation.
Your ovaries are not broken. They are responding correctly to an incorrect hormonal environment. When insulin is chronically elevated, the theca cells lining your ovarian follicles receive a signal to make more androgens — primarily testosterone. Those elevated androgens stall the normal growth and maturation of the follicle. The egg gets stuck. The follicle doesn’t rupture. You don’t ovulate. That stalled follicle becomes the “cyst” we see on ultrasound — which is really just an arrested follicle, not a true cyst at all. [4]
Fix the insulin environment, and you fundamentally change what your ovaries are doing. That’s why addressing insulin resistance — not just managing symptoms with birth control pills — is the root-cause approach.
But you cannot fix what you have not measured. And right now, a significant percentage of women with PCOS have never had their fasting insulin tested.
This week: what to do before your next appointment
You don’t have to wait for the medical system to catch up. Here is what I want you to do.
1. Request fasting insulin with your next blood draw. Not just fasting glucose. Not just HbA1c. Specifically ask for “fasting insulin.” It is a standard lab test available at virtually every laboratory. It may require you to explicitly request it, because it is not part of the standard PCOS panel most physicians use. Ask anyway.
2. Calculate your own HOMA-IR. Once you have your fasting glucose (in mmol/L) and fasting insulin (in μIU/mL), use this formula: (fasting glucose × fasting insulin) ÷ 22.5. If you are in the US and your glucose is in mg/dL, divide it by 18 first to convert to mmol/L. A result above 2.5 is clinically significant.
3. Ask for AMH while you’re at it. Anti-Müllerian hormone is no longer just a fertility marker. Recent research has established it as a biomarker of PCOS disease activity — and emerging evidence suggests it plays a role as a neuroactive hormone in PCOS pathogenesis. [1] If you haven’t had it tested, add it to the list.
4. Know your number before you make any treatment decisions. Whether you’re considering metformin, GLP-1 therapy, inositol supplementation, or a dietary approach, your HOMA-IR result will fundamentally shape which intervention is most likely to work for you. These are not interchangeable. The correct path depends on what your insulin is actually doing.
5. If your physician won’t order it, ask why. You are entitled to an explanation. “Your glucose is normal” is not an explanation for why fasting insulin testing is inappropriate in a woman with PCOS symptoms. If you are not getting satisfactory answers, seek a second opinion from a physician with specific PCOS metabolic expertise.
Coming in Part 2 — for paid subscribers
Knowing your HOMA-IR number is the first step. Knowing what to do with it is the second — and it’s where most women (and many physicians) get lost.
Part 2 of The IR Files is for paid subscribers. It covers exactly what I do in the clinic once I have a HOMA-IR result in hand: which interventions I recommend at which thresholds, how I think about the metformin versus inositol versus GLP-1 decision, what the right dietary architecture looks like for the insulin-resistant PCOS phenotype versus the lean phenotype, and the conversation I have with patients about what the next 5 years looks like if we address this now versus if we don’t.
It is the protocol behind the diagnosis. And it is the piece that most women with PCOS have never been given.
→ Subscribe to access Part 2: What To Do When Your Labs Come Back “Normal” But You Still Feel Awful
PCOS is the most common endocrine disorder in women of reproductive age. Up to 70% of affected women remain undiagnosed. And of those who are diagnosed, a substantial percentage have never had their insulin resistance properly measured.
That is not a coincidence. It is a systems failure. And naming it clearly is the first step toward fixing it.
If this post changed how you understand your own labs — or prompted you to finally ask for a test you should have had years ago — share it. The woman in your life who needs to read this probably isn’t going to find it unless you send it to her.
— Dr. Herman Weiss, MD, MBA, FACOG
CEO & Founder, ProvationLife™ | Host, The Metabolic Fix
References
[1] Dokras A et al. “Polycystic ovary syndrome in 2025 — insights and innovations.” Fertility & Sterility. Published online September 22, 2025. PMID: 40992713.
[2] Liu R et al. “Research progress on insulin resistance in polycystic ovary syndrome.” Reprod Dev Med. 2025;9(2):119–128. doi:10.1097/RD9.0000000000000131.
[3] Matthews DR et al. “Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma insulin and glucose concentrations in man.” Diabetologia. 1985;28(7):412–419. doi:10.1007/BF00280883.
[4] StatPearls. “Polycystic Ovarian Syndrome.” Updated July 7, 2025. National Library of Medicine. ncbi.nlm.nih.gov/books/NBK459251/
[5] Office on Women’s Health. “Polycystic Ovary Syndrome.” womenshealth.gov. Reviewed 2023.
[6] Dokras A et al. “PCOS as a cardiovascular disease risk-enhancing factor.” Fertility & Sterility. September 2025. PMID: 40992713.
This article is for educational purposes. It does not constitute medical advice. Please consult a qualified physician before making any changes to your care.
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