What is PCOS?

Polycystic Ovary Syndrome (PCOS) affects an estimated 1 in 10 women in the UK, making it one of the most common hormone-related conditions in women of reproductive age and a leading cause of ovulatory infertility. Worldwide, it’s thought to affect over 100 million women.

The name “PCOS” can be misleading. It’s actually a collection of symptoms that may have different underlying drivers – and not everyone with PCOS has cysts on their ovaries. In fact, around 20% of women without PCOS have cysts, while about 30% of women with PCOS do not.

So, what is it?
PCOS is often described as a complex endocrine condition involving hormonal and inflammatory changes that can disrupt the development of ovarian follicles. This can lead to delayed or absent ovulation, resulting in irregular or missed periods. In practice, PCOS may affect menstrual cycles, weight regulation, fertility, and other aspects of health.

Research suggests women with PCOS may also have a higher risk of metabolic complications such as insulin resistance, type 2 diabetes, altered cholesterol (dyslipidaemia), and potentially cardiovascular concerns.

Some of the more common symptoms of PCOS include:

• Insulin resistance
• Elevated androgens (or ‘male hormones’)
• Mid-cycle or ovulatory pain
• Acne or oily skin
• Unwanted hair growth on the face or body (hirsutism)
• Male-pattern hair thinning or hair loss
• Unwanted weight gain or difficulty losing weight
• Mood changes such as low mood, anxiety or irritability
• Sleep issues, including sleep apnoea

What are androgens?

Androgens are hormones such as testosterone, androstenedione, and dehydroepiandrosterone (DHEA). It’s normal to have some androgens – they support mood, libido, and bone health.

In PCOS, higher-than-average androgen levels (hyperandrogenism) are common. This is linked with difficulties ovulating, irregular periods, weight changes, unwanted hair growth, and acne. Hyperandrogenism is therefore considered both a clinical feature and a contributing factor in PCOS.

Factors which may contribute to PCOS

Family history

• PCOS can run in families. If a close female relative has PCOS, your likelihood of developing it may be higher.
• Genes may increase susceptibility, while environment and lifestyle may influence how strongly these genes are expressed.

Insulin and blood sugar balance

• High insulin levels may reduce sex hormone-binding globulin (SHBG), leaving more free testosterone available and contributing to symptoms.
• Insulin can also stimulate the ovaries and pituitary gland, influencing androgen production.
• Diets high in sugar and refined carbohydrates, combined with other factors such as stress, smoking, alcohol, sleep deprivation, some medications, and environmental exposures, may contribute to insulin resistance over time.

Inflammation

• Chronic low-grade inflammation is common in PCOS and may influence ovarian function and androgen production.
• Visceral fat (fat stored around the abdomen) can secrete inflammatory molecules, which in turn may worsen insulin resistance, creating a cycle that fuels symptoms.
• Lifestyle factors such as smoking, alcohol, ultra-processed foods, and chronic stress can add to overall inflammatory load.
• Gut health, infections, autoimmune activity, and food intolerances may also play a role in some cases.

Adrenal androgens and stress

• The adrenal glands produce stress hormones and some androgens. In PCOS, adrenal androgens may account for 20–30% of the elevated hormone levels seen.
• Ongoing stress may therefore play a role in symptom expression, even in women who are not insulin resistant or do not have ovarian cysts.
• Research suggests cortisol regulation may be altered in PCOS, potentially contributing to changes in weight, appetite, menstrual cycles, and immunity.

Exposure to endocrine-disrupting chemicals

• Certain environmental chemicals, sometimes called xenoestrogens (such as BPA in plastics), may mimic or interfere with hormone activity.
• Studies suggest they may contribute to insulin resistance, inflammation, and hormone imbalance, although more research is needed.

Post-pill hormone changes

• Some people notice PCOS-like symptoms after stopping the contraceptive pill. This does not mean the pill causes PCOS, but rather that hormonal shifts can temporarily mimic or unmask symptoms. PCOS itself is a longer-term condition with complex causes.

In reality, PCOS is often the result of a combination of these factors, with different drivers in different individuals.

Next steps

If you’d like to learn more about PCOS and explore nutrition and lifestyle approaches that may support your symptoms, you’re welcome to book a free call here.

Please note: we do not diagnose or treat PCOS. Nutrition and lifestyle support can complement medical care, but it is important to consult your GP for diagnosis, medical advice, and management.