Polycystic ovary syndrome (PCOS) is one of the most common hormonal conditions affecting women in the UK, yet it is often misunderstood or diagnosed late, sometimes years after symptoms first appear. Because it can affect periods, skin, hair, weight and fertility all at once, many women see several different clinicians before the pieces are joined together into a single diagnosis. This guide explains what PCOS is, how it is recognised and diagnosed, the treatment options a UK clinician may discuss with you, and when it is worth seeing a doctor.
What is PCOS and what causes it
PCOS is a common hormonal condition thought to affect around 1 in 10 women of reproductive age in the UK. It involves a combination of higher-than-typical androgen (male-type hormone) levels, irregular or absent ovulation, and, in many but not all cases, ovaries that appear to contain a higher number of small follicles on ultrasound. Despite the name, having "polycystic" ovaries on a scan does not necessarily mean a person has the syndrome, and someone can have PCOS without this ovarian appearance at all.
The exact cause of PCOS is not fully understood, but it tends to run in families and is closely linked with insulin resistance, where the body's cells respond less well to insulin. This can cause the body to produce more insulin, which in turn encourages the ovaries to produce more androgens, feeding into the pattern of symptoms described below. PCOS is not caused by anything a person has done, and it is not the result of poor diet or lack of exercise, although lifestyle factors can influence how symptoms are managed.
Recognising the symptoms
PCOS symptoms vary considerably from person to person, both in which symptoms appear and how noticeable they are. The most common include:
- Irregular, infrequent or absent periods, often the first sign that prompts someone to seek advice
- Excess hair growth on the face, chest or back (hirsutism), linked to higher androgen levels
- Acne or oily skin that persists beyond the teenage years or develops in adulthood
- Thinning hair or male-pattern hair loss on the scalp
- Weight gain, particularly around the waist, or difficulty losing weight
- Difficulty conceiving, due to irregular or absent ovulation
- Skin tags or darkened patches of skin, particularly around the neck or armpits
Not everyone with PCOS experiences every symptom, and severity differs widely. Some women are diagnosed only when investigating fertility, while others notice skin and hair changes years before any period irregularity becomes obvious. It is also worth knowing that PCOS is associated with a higher likelihood of low mood and anxiety, which is thought to relate both to the hormonal changes involved and to the day-to-day impact of visible symptoms such as acne or excess hair growth; this is a recognised part of the condition and one that is reasonable to raise with your clinician alongside the physical symptoms.
How PCOS is diagnosed
There is no single test for PCOS. In the UK, diagnosis is usually based on having at least two of three features, once other possible causes have been ruled out: irregular or absent ovulation, clinical or biochemical signs of higher androgen levels (such as acne, excess hair growth or blood test results), and polycystic ovaries seen on a pelvic ultrasound.
A typical assessment involves a discussion of your periods and any symptoms, a blood test to check hormone levels and rule out other conditions with similar features (such as thyroid problems), and sometimes a pelvic ultrasound scan. This can usually be arranged by a GP, though referral to a gynaecologist or endocrinologist is sometimes needed, particularly if symptoms are complex or fertility is a concern.
It can take time to reach a firm diagnosis, partly because symptoms overlap with other conditions and partly because the diagnostic process itself has several steps. If you feel your symptoms are not being taken seriously, it is reasonable to ask directly whether PCOS is being considered and what tests would help confirm or rule it out; taking a note of your cycle length and any skin or hair changes over a few months can also help your clinician build a clearer picture.
Treatment options for periods, skin and hair, and fertility
There is no cure for PCOS, so treatment focuses on managing the symptoms that matter most to you, which can change over time depending on whether you are trying to conceive. NICE published its first dedicated UK guidance on PCOS in 2026, with final guidance expected later in the year, and it sets out a clearer treatment pathway than existed previously.
For irregular or absent periods, a clinician may discuss progestogens or a combined contraceptive pill such as Microgynon, which can help regulate the cycle and protect the lining of the womb. For excess hair growth and acne, options include the combined pill or a medicine called spironolactone, which reduces the effect of androgens on the skin and hair follicles; hair removal methods such as laser or electrolysis are also commonly used alongside medical treatment. For those with signs of insulin resistance, metformin may be considered to support metabolic health, although it is used off-label for this purpose and your clinician will explain what this means for you.
For those trying to conceive, clomifene is usually the first fertility medicine considered, as it encourages the monthly release of an egg from the ovaries. If this alone is not effective, other options, including metformin alongside it or, less commonly, a minor surgical procedure called laparoscopic ovarian drilling, may be discussed with a fertility specialist. Lifestyle measures, covered next, are often recommended alongside medical treatment rather than instead of it.
PCOS, weight and insulin resistance
Insulin resistance is common in PCOS and can make weight gain more likely and weight loss more difficult than for someone without the condition, which can be frustrating for people who feel they are doing everything right. This is a genuine physiological effect of the condition, not a lack of willpower.
Even so, evidence suggests that a modest reduction in weight, in the region of 5 to 10 percent of body weight for those who are above a healthy weight, can meaningfully improve symptoms such as irregular periods and improve the chances of ovulation and conception for some women. Where lifestyle measures alone are not enough, and other criteria are met, a clinician may discuss whether a structured weight management programme is appropriate; our guide on who is eligible for medical weight management in the UK explains how these pathways generally work.
When to see a doctor
It is worth seeing a GP if your periods are absent or very irregular for more than three months, if you notice new or worsening acne, excess hair growth or scalp hair thinning, or if you have been trying to conceive for 12 months (or 6 months if you are over 35) without success. It is also worth seeking advice if you are concerned about your risk of conditions linked with PCOS, such as type 2 diabetes, high blood pressure and, for those with very infrequent periods, changes to the lining of the womb, since your clinician can arrange appropriate monitoring and advise on how often this should be reviewed.
A PCOS diagnosis is not a single event but the start of an ongoing relationship with your GP or a specialist, since which symptoms matter most to you is likely to change over the years, for example moving from managing acne in your twenties to focusing on fertility later on, and then to metabolic health beyond that. Regular check-ins allow your treatment plan to be adjusted as your priorities and circumstances change.
PCOS is a long-term condition, but with the right combination of lifestyle measures and, where appropriate, medical treatment, most of its symptoms can be managed effectively. Our Women's Health library also covers related topics including combined vs progestogen-only contraception, hair loss in women, and the acne treatment ladder, all of which can be relevant to managing PCOS symptoms day to day.