PCOS and Insulin Resistance: What You Need to Know

What is insulin resistance?

Insulin is a hormone made by your pancreas that helps move glucose (sugar) from your blood into your body’s cells, where it can be used for energy. When, over time and with increased levels, cells in the muscles, liver, and fat tissue become less responsive to insulin’s signal, your pancreas compensates by releasing more. This is called insulin resistance.

Over time, if insulin levels stay high (known as hyperinsulinaemia), the system becomes strained. This increases the risk of higher blood sugar levels and, in the long term, type 2 diabetes.

The latest international PCOS guidelines highlight that insulin resistance is a common feature of PCOS and recommend assessing blood glucose control with an oral glucose tolerance test (OGTT), rather than measuring insulin directly.

Why insulin resistance happens in women with PCOS

Insulin resistance can affect anyone, but it’s especially common in PCOS due to a mix of genetic, hormonal, and metabolic factors, not simply weight or diet.

Key factors include:

1. Cellular insulin signalling changes
Women with PCOS can have differences in how their cells respond to insulin, even at a healthy weight. The muscles and fat tissue don’t take up glucose efficiently, so the pancreas produces more insulin to compensate.

2. Androgen excess
High androgen levels, one of the defining features of PCOS, can reduce how well the body responds to insulin. Meanwhile, high insulin can also drive-up androgen levels, creating a vicious cycle that reinforces both problems.

3. Visceral fat and inflammation
Fat stored around the abdomen produces inflammatory molecules that interfere with insulin’s action. Even small reductions in waist size can make a measurable difference to insulin sensitivity.

4. Genetic predisposition
Insulin resistance and type 2 diabetes often run in families. Genetic factors linked to PCOS can affect how the body regulates insulin and glucose metabolism.

5. Cellular energy and oxidative stress
Emerging research suggests that reduced mitochondrial efficiency (how cells produce energy) and oxidative stress can also impair insulin function in women with PCOS.

These overlapping mechanisms explain why insulin resistance can occur in both lean and overweight women with PCOS, and why it requires a personalised, whole-body approach.

Why hyperinsulinaemia makes PCOS symptoms worse

Persistently high insulin levels can influence other hormone systems and worsen many PCOS symptoms.

Androgen excess
High insulin stimulates the ovaries to produce more testosterone and lowers sex hormone-binding globulin (SHBG), increasing the amount of active testosterone in circulation. This contributes to acne, oily skin, and excess hair growth.

Ovulation disruption
Elevated insulin and androgens can disrupt the hormonal feedback loop needed for ovulation, leading to irregular or absent periods and difficulty conceiving.

Weight management challenges
Insulin promotes fat storage, especially around the abdomen. This creates a cycle where higher insulin makes weight loss more difficult, and higher fat levels worsen insulin resistance.

Cravings and appetite changes
Fluctuating blood sugar and insulin can disrupt hunger hormones such as leptin and ghrelin, leading to intense sugar cravings and a feeling of never feeling full.

Mood and energy
Blood sugar swings can affect energy and concentration. Many women report fatigue, brain fog, or irritability that improve once blood sugar becomes more stable.

Signs and symptoms of insulin resistance

Insulin resistance develops gradually, so it’s easy to miss. While there is no single symptom, these patterns are common among women with PCOS:

• Strong sugar or carbohydrate cravings
• Feeling tired, shaky, or irritable between meals
• Difficulty losing weight despite a balanced diet
• Weight gain mainly around the middle
• Feeling hungry again soon after eating
• Fatigue after carbohydrate-rich meals
• Darkened, velvety skin patches on the neck or underarms (acanthosis nigricans)
• Acne, oily skin, or unwanted hair growth
• Irregular or missing periods
• Blood tests showing raised triglycerides, low HDL cholesterol, or elevated glucose or HbA1c

Recognising these early signs allows you to take proactive steps through nutrition and lifestyle before complications develop.

Practical next steps if you’re concerned

If several of these symptoms sound familiar, here are steps to support metabolic and hormonal balance – but always seek guidance from your GP or a registered nutrition professional before making major changes.

Request appropriate testing
Ask your GP whether an Oral Glucose Tolerance Test (OGTT) is suitable for you. It’s the most sensitive way to assess glucose handling in PCOS.

Review your wider metabolic picture
Blood pressure, cholesterol, liver function, and waist measurement all contribute to understanding overall metabolic health.

Focus on balanced eating
There is no single “best” diet for PCOS, despite what influencers might try and tell you! It depends on the individual. However, it is best to focus on:

• Protein at every meal to support satiety
• Fibre-rich vegetables to slow glucose release
• Whole-food carbohydrates, such as veggies and legumes, in moderate portions
• Healthy fats to support hormones

Over-restricting carbohydrates can cause fatigue and cravings, so aim for balance rather than extremes.

Move regularly
Regular movement improves insulin sensitivity. A combination of brisk walking, cycling, or swimming along with weight or strength training offers broad benefits. Consistency matters more than intensity.

Prioritise sleep and stress management
Poor sleep and chronic stress raise cortisol, which can worsen insulin resistance. Good sleep hygiene and simple stress-reduction techniques can make a noticeable difference.

Insulin resistance and diabetes risk
Research shows that women with PCOS are at a higher risk of developing impaired glucose tolerance and type 2 diabetes, even at a healthy weight. This happens because insulin resistance often develops earlier and progresses more quickly in PCOS. Studies show that women with PCOS have a four- to eight-fold increased risk of type 2 diabetes compared with women without PCOS.

Over time, if insulin levels stay high, the pancreas may struggle to keep up with demand, leading to rising blood glucose. Early identification and consistent lifestyle changes can significantly reduce this risk.

Regular blood sugar checks and ongoing metabolic monitoring are therefore key parts of long-term PCOS care. The goal isn’t restriction - it’s understanding and prevention.

For a refresher on the fundamentals, see What is PCOS?

If you’d like to understand your blood sugar and hormone balance better, book a consultation to create a tailored, evidence-based nutrition and lifestyle plan designed to support PCOS and insulin sensitivity.

This article is for educational purposes only and does not replace medical advice or diagnosis.