PCOS is one of the most common hormone conditions in women of reproductive age. It is also one of the most misunderstood — the name suggests cysts on the ovaries, which is misleading. This page explains what PCOS actually is, how it is diagnosed, and what genuinely helps.

What PCOS is — and what the name gets wrong

PCOS is a hormonal condition in which the ovaries do not release eggs regularly, and the body produces slightly more male-type hormones (androgens) than usual.

The "cysts" in the name are not cysts at all. They are simply the normal small follicles of the ovary, present in larger numbers than usual and visible on a scan. They are harmless, they do not need removing, and they are not the cause of the problem.

Symptoms

PCOS shows itself differently in different women. You may have all of these, or only one or two:

  • Irregular or absent periods — the most common feature
  • Difficulty conceiving, because ovulation is irregular
  • Excess hair growth on the face, chest or abdomen
  • Acne that persists beyond the teenage years
  • Thinning hair on the scalp
  • Weight gain, or difficulty losing weight
  • Darkened patches of skin at the neck, armpits or groin

Symptoms often begin in the late teens or early twenties, though many women are only diagnosed later, when they have trouble conceiving.

How PCOS is diagnosed

The diagnosis is made when two out of three of the following are present, and other conditions that can look similar have been excluded:1

  1. Irregular or absent ovulation — usually shown by irregular or absent periods
  2. Raised androgens — either on a blood test, or clearly visible as excess hair growth or persistent acne
  3. Typical appearance of the ovaries on ultrasound — many small follicles

Two practical points worth knowing:

  • In adult women, an AMH blood test can now be used instead of the ultrasound scan.1
  • In adolescents, the ultrasound appearance is not used at all, because many normal teenage ovaries look this way. Diagnosis in this age group is based on symptoms alone, and is sometimes deliberately deferred.1

Your doctor will also check thyroid function and prolactin, since both can produce a similar picture.

What matters most: lifestyle and a healthy weight

This is the foundation of PCOS management, and it is worth saying plainly: there is no medicine that works as well as getting your weight into a healthy range if it is currently above it.

  • Even a modest weight loss — a few kilograms — can restore regular periods and ovulation in many women.1
  • Regular physical activity improves how your body handles insulin, whether or not you lose weight.
  • No single diet is proven better than another in PCOS. What works is one you can maintain: less refined sugar and refined carbohydrate, more vegetables and fibre, sensible portions.1

If your weight is already in the healthy range, the goal is to keep it there — weight gain tends to worsen PCOS symptoms.

None of this is a criticism. PCOS makes weight harder to lose, not easier, and that is a feature of the condition rather than a failure of effort. But it is also the single most effective lever you have.

Medicines

For irregular periods and excess hair or acne

The combined oral contraceptive pill is the usual first treatment. It regulates periods, protects the lining of the womb, and improves acne and excess hair over several months.1

Protecting the womb lining matters. If periods are very infrequent, the lining can become too thick over time — see our article on endometrial hyperplasia.

Metformin

Metformin is used in selected patients — particularly those with a high BMI and those with impaired glucose tolerance. It works on the metabolic side of PCOS rather than on the ovaries directly.1

It is not needed by every woman with PCOS, and it is not a weight-loss drug. Whether it is right for you is a decision to make individually.

When you are trying to conceive

Letrozole is the first-line treatment for women with PCOS who are not ovulating and want to conceive. Clomifene is used in selected patients, and gonadotrophin injections are the second-line option.1 There is more detail in our article on ovulation induction.

Long-term health

PCOS is not only about periods and fertility. Over the longer term it carries a higher risk of:

  • Type 2 diabetes — which is why blood sugar should be checked periodically3
  • High blood pressure and raised cholesterol
  • Thickening of the womb lining, if periods are very infrequent for years
  • Low mood and anxiety, which are commoner in PCOS and worth mentioning to your doctor1

The good news is that these risks are largely modifiable. The same lifestyle measures that improve your periods also reduce these long-term risks — which is why they are worth the effort even in years when you are not trying to conceive.

Living with PCOS

  • Aim for regular meals rather than long gaps followed by large meals.
  • Build in activity you will actually keep doing — walking counts.
  • Ask about cosmetic options for excess hair if it bothers you; it is a legitimate concern, not a vanity.
  • Say so if you are struggling emotionally. PCOS affects mood and self-image, and that deserves attention alongside the physical symptoms.
  • Have your blood pressure and blood sugar checked at intervals, even when you feel well.

When to see a doctor

Please make an appointment if you have:

  • Fewer than four periods a year, or periods that have stopped
  • Difficulty conceiving after a year of trying, or six months if you are over 35
  • Rapidly increasing hair growth, or a deepening voice — these need a different assessment
  • Very heavy or prolonged bleeding when a period does come
  • Symptoms affecting your mood or confidence

The takeaway

PCOS is common, manageable and does not stop most women having children. Lifestyle and a healthy weight do more than any tablet. Medicines have a clear role — the pill for cycle control, metformin for selected women with metabolic features, letrozole when you are trying to conceive — and long-term health checks matter as much as the day-to-day symptoms.

References

  1. Teede HJ, Tay CT, Laven J, Dokras A, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Hum Reprod. 2023;38(9):1655–79. Available from: https://pubmed.ncbi.nlm.nih.gov/37580037/
  2. NHS. Polycystic ovary syndrome (PCOS) [Internet]. London: NHS; [cited 2026 Jul 22]. Available from: https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/
  3. Royal College of Obstetricians and Gynaecologists. Polycystic ovary syndrome (PCOS): what it means for your long-term health [Internet]. London: RCOG; [cited 2026 Jul 22]. Available from: https://www.rcog.org.uk/for-the-public/browse-our-patient-information/polycystic-ovary-syndrome-pcos-what-it-means-for-your-long-term-health/