What are the main symptoms of PCOS?

The most common symptoms include irregular or infrequent periods, excess hair growth (hirsutism), persistent acne, scalp hair thinning, and difficulty losing weight. Many people with PCOS also experience insulin resistance, fatigue, mood changes, and subfertility. PCOS presents differently in different people — you may have some but not all of these symptoms.

Do you need polycystic ovaries on ultrasound to be diagnosed with PCOS?

No. PCOS is diagnosed using the Rotterdam criteria, which requires at least two of three features: irregular or absent ovulation, clinical or biochemical signs of elevated androgens, or polycystic-looking ovaries on ultrasound. You can be diagnosed with PCOS without the characteristic ovarian appearance if you meet the other two criteria.

Can lifestyle changes improve PCOS symptoms?

Yes, significantly. A low-glycaemic diet, regular exercise (especially resistance training), quality sleep, and stress management can meaningfully improve insulin resistance, reduce androgen levels, and restore more regular cycles. These lifestyle changes are often recommended as first-line treatment alongside or before medication, as they address the underlying metabolic drivers of PCOS.

Can you have PCOS if you are not overweight?

Yes. Lean PCOS affects people with a normal BMI. Insulin resistance and elevated androgens can occur regardless of body weight, and thin people with PCOS sometimes face longer diagnostic delays because providers may not consider PCOS without visible weight issues. If you have irregular periods and signs of androgen excess, it is worth asking about PCOS regardless of your weight.

PCOS: Understanding Symptoms, Causes, and Management Strategies

Polycystic ovary syndrome (PCOS) is one of the most common hormonal disorders affecting people with ovaries — estimated to affect 8–13% of reproductive-age women globally, with up to 70% undiagnosed. It's associated with irregular periods, excess androgens, and characteristic ovarian appearance on ultrasound, but it's actually a metabolic condition that affects the whole body, not just the reproductive system.

What Is PCOS?

PCOS is a complex hormonal and metabolic disorder characterised by a cluster of symptoms — not a single disease. Its name is a bit misleading: "polycystic ovaries" describes a specific ultrasound appearance (many small follicles), but you don't need polycystic ovaries to have PCOS, and having polycystic-looking ovaries doesn't mean you have PCOS.

At its core, PCOS involves disrupted ovulation, often driven by insulin resistance and elevated androgen (male hormone) levels. These hormonal imbalances create a cascade of effects throughout the body.

How Is PCOS Diagnosed? The Rotterdam Criteria

PCOS is diagnosed using the internationally accepted Rotterdam criteria: a diagnosis requires at least 2 of the following 3 features:

Irregular or absent ovulation (often presenting as irregular, infrequent, or absent periods)
Clinical or biochemical signs of hyperandrogenism (elevated testosterone or androgen markers on blood tests, or physical signs like excess hair growth, acne, or scalp hair thinning)
Polycystic ovarian morphology on ultrasound (12 or more small follicles in each ovary, and/or increased ovarian volume)

Other conditions must first be ruled out before a PCOS diagnosis is made — including thyroid disorders, elevated prolactin, and congenital adrenal hyperplasia.

PCOS has four phenotypes: Depending on which combination of Rotterdam criteria you meet, PCOS can look quite different from person to person — ranging from classic PCOS (all three criteria) to ovulatory PCOS (hyperandrogenism + polycystic ovaries but regular cycles) to lean PCOS (no weight issues but other features present).

Common Symptoms

Irregular Periods

Cycles longer than 35 days, fewer than 8 periods per year, or absent periods are hallmarks of PCOS. This happens because without regular ovulation, the hormonal cycle doesn't complete properly — oestrogen builds up without the progesterone that normally follows ovulation, eventually leading to unpredictable or irregular cycles.

Excess Androgens

Elevated androgens are responsible for many of the more distressing symptoms of PCOS:

Hirsutism: Excess dark or coarse hair on the face, chest, abdomen, or back
Acne: Persistent hormonal acne, often along the jaw, chin, and chest
Androgenic alopecia: Scalp hair thinning at the crown or hairline (while having excess body hair)

Insulin Resistance and Weight

Up to 70% of people with PCOS have some degree of insulin resistance — meaning cells don't respond effectively to insulin. This causes the pancreas to overproduce insulin, which in turn stimulates the ovaries to produce more androgens. This creates the core hormonal loop of PCOS.

Insulin resistance is associated with difficulty losing weight, weight gain (particularly around the abdomen), fatigue, and sugar cravings. Importantly, thin people can also have PCOS and insulin resistance — it doesn't only present in those who are overweight.

Other Common Features

Mood changes, depression, and anxiety (significantly higher rates than the general population)
Sleep disturbances, including sleep apnoea
Subfertility or difficulty conceiving due to irregular ovulation
Long-term metabolic risks if unmanaged: type 2 diabetes, elevated cholesterol, and cardiovascular disease

Management Strategies

PCOS has no cure, but its symptoms can be effectively managed through lifestyle and medical approaches. Management is highly individual — what works depends on your symptoms, goals (fertility vs. symptom management), and overall health.

Diet: Low GI and Anti-Inflammatory

The most evidence-backed dietary approach for PCOS addresses insulin resistance directly:

Low glycaemic index (GI) eating: Prioritise complex carbohydrates that release glucose slowly — oats, legumes, sweet potatoes, most fruits, and non-starchy vegetables. Reduce refined carbohydrates, white bread, sugary drinks, and processed snacks.
Anti-inflammatory foods: Oily fish, olive oil, turmeric, berries, leafy greens, and nuts reduce systemic inflammation that contributes to hormonal disruption.
Adequate protein: Protein at each meal helps stabilise blood sugar. Aim for lean proteins, legumes, and fish.

Exercise

Regular physical activity is one of the most effective interventions for PCOS — it improves insulin sensitivity, supports weight management, and directly reduces androgen levels. A combination of:

150 minutes per week of moderate aerobic exercise (walking, cycling, swimming)
2–3 sessions per week of resistance training (which is particularly effective at improving insulin sensitivity)

Sleep and Stress

Chronic sleep deprivation and high stress elevate cortisol, which worsens insulin resistance. Prioritising 7–9 hours of quality sleep and regular stress-reduction practices (exercise, mindfulness, time in nature) can meaningfully improve PCOS symptoms.

Supplements with Evidence

Inositol (myo-inositol and D-chiro-inositol): The most studied supplement for PCOS. Multiple trials show it improves insulin sensitivity, reduces androgen levels, and may restore ovulation in some people. The evidence is strongest for a 40:1 ratio of myo-inositol to D-chiro-inositol.
Vitamin D: Deficiency is extremely common in PCOS and associated with worsened insulin resistance. Supplementing where deficient can improve metabolic and hormonal markers.
Omega-3 fatty acids: Anti-inflammatory effects and some evidence for reducing testosterone levels.

Medical Treatments

Depending on your goals, a doctor may recommend:

Combined oral contraceptive pill: Regulates periods, reduces androgen effects, improves acne and hirsutism. Does not treat the underlying causes of PCOS.
Metformin: An insulin-sensitising medication that can improve cycle regularity and metabolic markers. Increasingly used in PCOS management alongside lifestyle measures.
Letrozole or clomiphene: Ovulation-inducing medications for people with PCOS trying to conceive.
Spironolactone: An anti-androgen medication used to manage hirsutism and acne.

Tracking Irregular Cycles with PCOS

Standard cycle tracking apps assume regular cycles — which makes them unhelpful (and potentially misleading) for people with PCOS. Mozi's irregular cycle mode focuses on symptom logging and pattern observation rather than generating predictive dates based on an assumed 28-day cycle. This makes tracking more honest and useful for understanding your cycle even when periods are unpredictable.

Medical disclaimer: PCOS is a medical diagnosis. This article is for educational purposes only. If you suspect you may have PCOS, or if you've been diagnosed and are managing it, please work with a qualified healthcare professional to develop a personalised treatment plan.