Weight and your health

Weight and polycystic ovary syndrome (PCOS)

PCOS affects around 1 in 10 women in the UK. Insulin resistance makes weight gain more likely and weight loss harder — but even modest loss can make a real difference to symptoms.

Published by Well Medicare, a GPhC-registered pharmacy in Marylebone, London · Last updated October 2026

Key points
  • Many women with PCOS have insulin resistance, which encourages fat storage around the middle.
  • Losing 5% of your body weight can improve periods, symptoms and fertility for many women.
  • Most weight-loss medicines are not suitable if you are pregnant or trying to conceive — always tell the prescriber.

How PCOS affects weight

PCOS is a hormonal condition that can cause irregular or absent periods, excess hair growth, acne, thinning hair and difficulty getting pregnant. Many women with PCOS are insulin resistant: the body needs more insulin to control blood sugar, and higher insulin levels encourage fat storage — especially around the waist — and raise androgen (male hormone) levels, which can worsen symptoms. Excess weight then increases insulin resistance further.

Why losing weight helps

Because weight and insulin resistance feed each other, breaking the cycle helps on several fronts. Losing around 5% of your body weight can lead to more regular periods, improved fertility, less excess hair growth and a lower risk of type 2 diabetes, which is more common in women with PCOS.

What helps day to day

  • Steady blood sugar: base meals on protein, vegetables and high-fibre carbohydrates rather than refined starches and sugary drinks. See our nutrition guide.
  • Strength training: muscle improves insulin sensitivity. Our beginner’s guide is a good place to start.
  • Sleep and stress: poor sleep worsens insulin resistance and appetite.
  • Regular check-ups: your GP may check your blood sugar, cholesterol and blood pressure.

Medical weight-loss support and pregnancy

If your BMI is 30 or more, or 27 or more with a weight-related condition, you may be eligible for a medical weight-loss programme. Weight-loss medicines are generally not used during pregnancy, while breastfeeding, or when trying to conceive, and some need to be stopped well before trying for a baby. Tell the prescriber about your plans so they can advise you safely.

Not sure if medical weight loss is right for you?

Our free online assessment takes about five minutes. A GPhC-registered prescriber reviews it and only recommends treatment if it is safe and suitable for you.

Start the free assessment

Frequently asked questions

Can losing weight cure PCOS?

PCOS is a long-term condition, but losing weight can greatly reduce symptoms and improve fertility for many women.

Why is it so hard to lose weight with PCOS?

Insulin resistance and hormonal changes can increase appetite and make the body store fat more readily. It is harder, not impossible — and support can help.

Should I see my GP about PCOS?

Yes, if you have irregular periods or other symptoms. Your GP can confirm the diagnosis and check for related conditions such as type 2 diabetes.

This page is general health information. It does not replace advice from your GP or another healthcare professional who knows your history. If you have symptoms that worry you, contact your GP or NHS 111; in an emergency call 999. Prescription treatment is only supplied after an assessment by a registered prescriber.