PCOS and Insulin Resistance: Symptoms, Weight, Testing and Diet

Polycystic ovary syndrome (PCOS) and insulin resistance often occur together, but they are not the same condition. PCOS, recently renamed polyendocrine metabolic ovarian syndrome (PMOS) through a 2026 global consensus process, can affect periods, ovulation, androgen-related symptoms and metabolic health. Insulin resistance is common in PCOS, but not everyone with PCOS has it, and you cannot judge it from body size alone. Assessment usually looks at menstrual patterns, symptoms, glucose regulation, fertility goals and overall health.

What is PCOS, and why is it now called PMOS?

If you have PCOS, someone may have told you that every symptom comes back to insulin or weight. The reality is more complex. PCOS can affect periods, ovulation, androgen-related symptoms, fertility, metabolic health and emotional wellbeing, and different people can have very different combinations of symptoms. In 2026, a global consensus process led by Teede and colleagues selected polyendocrine metabolic ovarian syndrome (PMOS) as the new name for polycystic ovary syndrome (PCOS). The change reflects the condition’s broader endocrine and metabolic effects and avoids the misleading idea that ovarian “cysts” are required. Implementation is still underway, so PCOS remains widely used and is the term used throughout this article.

The World Health Organization (WHO) estimates that PCOS affects about 10–13% of women of reproductive age, and many remain undiagnosed. In adults, diagnosis generally requires at least two of three features after other possible causes have been excluded: irregular or absent ovulation, clinical or blood-test evidence of higher androgen levels, and polycystic ovarian morphology on ultrasound. The 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome also allows anti-Müllerian hormone (AMH) to be used instead of ultrasound in appropriate adults. You do not need ovarian “cysts” to have PCOS.

How are PCOS and insulin resistance connected?

Insulin is a hormone that helps glucose move from the bloodstream into cells, where it can be used or stored. With insulin resistance, cells respond less effectively to insulin. The pancreas may compensate by producing more insulin, which can keep blood glucose within the normal range for a time. This means insulin resistance can be present before blood glucose reaches the range used to diagnose prediabetes or type 2 diabetes. Insulin resistance is an important feature of PCOS, but it is not the only process involved. Genetics, androgen regulation, body-fat distribution and other endocrine and environmental factors can also contribute. In some people, higher insulin levels can increase active androgen levels and contribute to irregular ovulation, acne or excess facial and body hair. The relationship can work in both directions: PCOS can increase the likelihood of insulin resistance, while insulin resistance can worsen some metabolic and androgen-related features. But not everyone with PCOS has insulin resistance, and you can have insulin resistance without PCOS. “Lean PCOS” is a description rather than a separate diagnosis. Body size can influence metabolic risk, but it cannot tell you how well someone is handling glucose.

What are the symptoms of PCOS and insulin resistance?

Symptoms vary widely, and no single symptom confirms PCOS or insulin resistance. Common PCOS features can include:

• Irregular, infrequent or absent periods

• Heavy or prolonged bleeding in some people

• Acne or oily skin

• Excess facial or body hair, known as hirsutism

• Scalp hair thinning

• Difficulty conceiving because of irregular ovulation

• Weight gain or difficulty managing weight in some people

• Sleep problems, anxiety or low mood

Some people with insulin resistance develop acanthosis nigricans, which causes darker, thicker or velvety patches of skin, often around the neck, armpits or groin. It can be a clue, but its absence does not rule out insulin resistance. Fatigue can occur, but it is not specific to either condition. Poor sleep, heavy bleeding, iron deficiency, thyroid problems and other conditions can cause similar tiredness.

How do doctors test for insulin resistance in PCOS?

There is no single routine blood test that perfectly measures insulin resistance in everyday clinical care. The 2023 international guideline notes that clinically available insulin assays have limited value for routine management and should not be used on their own to diagnose insulin resistance. Doctors usually assess glycaemic status, meaning how well the body is managing glucose. The guideline identifies the 75 g oral glucose tolerance test (OGTT) as the most accurate test for assessing glucose regulation in PCOS, regardless of body mass index (BMI). If an OGTT cannot be performed, fasting plasma glucose or glycated haemoglobin (HbA1c) may be considered, although they are less accurate in this setting. An OGTT is particularly important when planning pregnancy or seeking fertility treatment because PCOS is associated with a higher risk of abnormal glucose regulation during pregnancy. A normal fasting glucose result does not necessarily mean insulin resistance is absent, and a fasting insulin result can be difficult to interpret because there is no single accepted cut-off for routine diagnosis.

Does insulin resistance cause weight gain in PCOS?

Insulin resistance may make weight management more difficult for some people, but it does not explain every change in body weight. Genetics, sleep, stress, medicines, food access, physical activity and the wider environment all matter. Higher levels of body fat, particularly around the abdomen, can also worsen insulin resistance. Lifestyle changes can improve insulin sensitivity, cardiovascular health and reproductive health even when the number on the scale changes only a little. Weight is one part of the picture, not a test for insulin resistance.

What is the best diet for PCOS and insulin resistance?

There is no single “best” diet for everyone with PCOS. The international guideline does not identify one dietary pattern as clearly superior, and you do not need to remove all carbohydrates, avoid gluten without another reason or follow a ketogenic diet simply because you have PCOS. A practical meal can include a suitable carbohydrate source, protein, vegetables or other fibre-rich foods, and healthy fats. Dal with vegetables and rice, roti with paneer or chana, or curd with fruit, seeds and nuts are simple examples. Pairing carbohydrate foods with protein and fibre can make meals more satisfying and may help moderate the glucose response. Insulin normally rises after eating, so carbohydrates do not need to be eliminated.

What about exercise?

Physical activity can improve insulin sensitivity, cardiovascular health, strength, mood and sleep even without major weight loss. Walking, resistance training, cycling, swimming and dancing can all count. Choose activities you can do consistently and safely.

Does sleep matter?

Yes. The international guideline reports that people with PCOS have a higher prevalence of obstructive sleep apnoea even after body mass index is taken into account. Loud snoring, gasping during sleep, waking unrefreshed or excessive daytime sleepiness deserves medical assessment.

What treatments can help?

Lifestyle support is an important part of PCOS care, but it is not a substitute for medical treatment when medicine, fertility support or treatment for specific symptoms is needed. Treatment may include hormonal medicines for irregular periods, acne or excess hair; metformin for metabolic features in some people; dermatological treatment; or fertility treatment when pregnancy is the goal. If pregnancy is not currently a goal, protecting the lining of the uterus also matters when periods are very infrequent. Going several months without a period should not simply be ignored.

When should you see a doctor?

Arrange a medical assessment if you frequently miss periods, go several months without one, develop new or worsening facial hair, acne or scalp hair thinning, or are trying to conceive and your periods are irregular. Persistent thirst, frequent urination or unexplained weight loss also need assessment because they can be signs of abnormal glucose regulation. Seek medical advice if you snore loudly, gasp during sleep or feel excessively sleepy during the day. Seek prompt medical care for very heavy bleeding, severe pelvic pain or rapidly developing signs of androgen excess, such as a deepening voice or marked changes over a short period.

Also read

• Hair Loss in Women: Causes, Shedding and What to Check

• Collagen for Acne Scars: What Skin Nutrition Can and Cannot Do

Medical Disclaimer

This article is for general educational purposes only and should not replace professional medical advice, diagnosis or treatment. If you have irregular periods, signs of higher androgen levels, concerns about blood glucose, fertility problems or other symptoms linked with PCOS or insulin resistance, speak to a qualified healthcare professional for individual assessment and appropriate testing.