PCOS and Insulin Resistance: What You Need to Know

If you have been reading about PCOS, you have almost certainly come across insulin resistance. It is one of the most discussed aspects of the condition, and for good reason: an estimated 50 to 70% of women with PCOS have some degree of insulin resistance, and it plays a central role in driving many PCOS symptoms. But what exactly is it, and what can you do about it?

What is insulin resistance?

Insulin is a hormone produced by your pancreas. Its main job is to help cells absorb glucose (sugar) from your blood to use as energy. When your cells become resistant to insulin, they stop responding to it effectively. Your pancreas compensates by producing more and more insulin, trying to force the glucose into cells that are not cooperating.

This creates a state of chronically elevated insulin (hyperinsulinaemia), and that excess insulin has downstream effects throughout your body.

How insulin resistance drives PCOS symptoms

Elevated insulin does not just affect blood sugar. It acts as a hormonal signal that disrupts multiple systems.

Androgen production. Excess insulin stimulates the ovaries to produce more testosterone. This is the direct mechanism linking insulin resistance to many of the most visible PCOS symptoms: acne, hirsutism, and hair loss.

SHBG suppression. Insulin suppresses the liver's production of SHBG (sex hormone binding globulin), the protein that binds testosterone and keeps it inactive. Lower SHBG means more free, active testosterone circulating in your body, amplifying androgen symptoms.

Ovulation disruption. The combination of elevated androgens and disrupted hormonal signalling interferes with the normal follicular development process, leading to irregular or absent ovulation, which in turn causes irregular periods.

Weight gain. Insulin is a storage hormone. Chronically elevated insulin promotes fat storage, particularly around the abdomen, and makes it harder to lose weight even with genuine effort. This is why so many women with insulin-resistant PCOS describe doing “everything right” and still struggling with their weight.

Cravings and hunger. Blood sugar instability caused by insulin resistance can trigger intense sugar and carbohydrate cravings, energy crashes (particularly in the afternoon), and a sense of hunger that feels disproportionate to what you have eaten.

Inflammation. Insulin resistance is associated with chronic low-grade inflammation, which may further worsen androgen production and metabolic dysfunction.

Not all PCOS involves insulin resistance

This is an important point. While insulin resistance is the most common metabolic feature of PCOS, it is not universal. Women with phenotype D (normoandrogenic PCOS) and some women with phenotype C (ovulatory PCOS) may have little or no insulin resistance. PCOS can also be driven primarily by adrenal factors, inflammation, or other mechanisms.

Framing all PCOS management around blood sugar control can be misleading if insulin resistance is not your primary driver. Testing is the only way to know.

How to test for insulin resistance

Standard glucose tests alone can miss insulin resistance entirely. Your fasting glucose can appear completely normal while your insulin levels are significantly elevated because your pancreas is working overtime to keep glucose in check.

The key tests are fasting insulin (the most direct measure of how much insulin your body is producing), fasting glucose (to pair with insulin for the HOMA-IR calculation), HOMA-IR (calculated from fasting insulin and glucose; values above approximately 2.5 suggest insulin resistance), and HbA1c (reflects average blood sugar over 2 to 3 months; useful for diabetes screening but less sensitive for early insulin resistance).

If your doctor only orders fasting glucose and HbA1c, you may want to specifically request fasting insulin and HOMA-IR. For a full breakdown of all PCOS-relevant blood tests, see our guide to PCOS blood tests.

Managing insulin resistance

The good news is that insulin resistance is one of the most responsive aspects of PCOS to intervention. Both lifestyle and medication approaches have strong evidence.

Nutrition. Low glycaemic index eating has the strongest evidence for improving insulin sensitivity in PCOS. The practical application: pair carbohydrates with protein, healthy fat, or fibre at every meal. Prioritise whole grains, vegetables, legumes, and lean proteins. Reduce added sugars and highly processed foods. Eat regularly rather than skipping meals, as blood sugar crashes can worsen the cycle.

Movement. Resistance training (weights, bodyweight exercises, resistance bands) is particularly effective for improving insulin sensitivity because muscle tissue is a major consumer of glucose. Combined aerobic and resistance exercise is recommended by clinical guidelines. A modest weight loss of 5 to 10% in women who are overweight can produce significant improvements in insulin sensitivity and ovulation rates.

Sleep. Poor sleep directly worsens insulin resistance. Prioritising 7 to 9 hours of consistent sleep supports metabolic health.

Stress management. Chronic stress elevates cortisol, which promotes insulin resistance. Stress management is not a luxury; it is a metabolic intervention.

Metformin. Guideline-endorsed by the Endocrine Society and ESHRE for improving insulin sensitivity in PCOS. Metformin works by reducing glucose production in the liver and improving cellular insulin sensitivity. It may also help restore ovulation. Common side effects include digestive discomfort, which often improves over time or with extended-release formulations. Discuss with your doctor.

Inositol. Myo-inositol and D-chiro-inositol (in a 40:1 ratio reflecting the physiological plasma ratio) have strong randomised controlled trial evidence for improving insulin sensitivity, reducing androgens, and supporting ovulation in PCOS. Not yet in all major international guidelines but widely used and studied. Discuss with your doctor before starting.

Monitoring over time

Insulin resistance is not a fixed state. It can improve with the right interventions and worsen with inactivity, poor sleep, stress, or weight gain. Regular monitoring (fasting insulin, glucose, HbA1c, and lipid panel) helps you and your doctor assess whether your management approach is working and adjust as needed.

Tracking how you feel alongside your lab results provides additional context. If your energy is improving, your cravings are reducing, and your cycles are becoming more regular, those are meaningful signals, even before your next blood draw.

This content is for informational purposes only. Always consult your healthcare provider before starting medications or supplements.