PCOS Explained: Why It’s Not About Ovarian “Cysts” at All

Polycystic ovary syndrome (PCOS) is one of the most misunderstood conditions in women’s health. Despite the name, PCOS is not really about having “polycystic” ovaries. Those small fluid-filled sacs seen on ultrasound aren’t true cysts at all — they’re immature follicles that never developed properly.

The real story? PCOS is driven by hormone imbalances — especially excess androgens (male-type hormones) and insulin resistance. These two factors create a feedback loop that explains why PCOS causes irregular periods, acne, excess hair growth, fertility struggles, and metabolic problems.

Let’s break down the science — and the latest evidence — so you can see what’s really happening in your body and why.

🔍 Myth-busting the name: PCOS isn’t about cysts

• In PCOS, the ovaries contain many small follicles (undeveloped eggs).

• They look like “cysts” on ultrasound, but they’re not dangerous or cancerous.

• These follicles build up because ovulation doesn’t occur regularly.

👉 Key point: The ovaries look “polycystic” because of hormone disruption, not the other way around.

⚖️ Core driver 1: Excess androgens

One of the defining features of PCOS is hyperandrogenism — higher-than-normal levels of hormones like testosterone and androstenedione.

• Androgens disrupt follicle maturation → no dominant egg develops.

• No ovulation = irregular or missed periods.

• High androgen levels also cause acne, hirsutism (unwanted face/body hair), and scalp hair thinning.

Ovarian theca cells (the hormone-producing cells around follicles) are unusually sensitive in PCOS, producing excess androgens even in response to normal signals.

👉 NHS: PCOS symptoms and causes

💉 Core driver 2: Insulin resistance

Here’s where PCOS goes beyond reproductive health into metabolism.

• Insulin resistance means cells don’t respond properly to insulin.

• To compensate, the body makes more insulin (hyperinsulinemia).

• High insulin stimulates the ovaries to produce more androgens.

• High insulin lowers SHBG (sex hormone binding globulin) in the liver → more free testosterone circulates in the blood.

This explains why insulin resistance is linked to so many PCOS symptoms.

👉 Key point: PCOS can affect women of all body types. Many lean women also have insulin resistance, although it’s more common and more severe in those who are overweight.

Sources:

• NIH: PCOS and insulin resistance
• Legro RS, J Clin Endocrinol Metab, 2013 【Retired guideline — see 2023 update below】

🔄 The vicious cycle: insulin ↔ androgens

1. Insulin resistance → high insulin.

2. High insulin → ovaries make more testosterone.

3. More testosterone → ovulation is disrupted → follicles accumulate in ovaries.

4. Disrupted ovulation → worsens hormone imbalance.

5. More androgens + weight changes → worsen insulin resistance.

This loop explains why PCOS symptoms often reinforce one another.

🧠 LH/FSH imbalance adds fuel

Normally, the brain releases LH (luteinising hormone) and FSH (follicle-stimulating hormone) in balance. In PCOS:

• LH levels are often higher relative to FSH.

• High LH → more ovarian androgen production.

• Low FSH → follicles don’t mature properly.

• The result = irregular or absent ovulation.

👉 This is why PCOS is strongly linked to infertility.

🌍 Beyond periods and fertility

Because PCOS affects multiple systems, its impact goes well beyond the ovaries:

• Metabolic health: 50–70% of women with PCOS have insulin resistance. Over half will develop prediabetes or type 2 diabetes by age 40.

• Heart health: Higher rates of cholesterol problems, high blood pressure, and metabolic syndrome.

• Endometrial cancer risk: Irregular ovulation means unopposed estrogen, which can cause endometrial thickening.

• Mental health: Higher rates of anxiety and depression, often linked to symptoms like weight changes, infertility, and hirsutism.

👉 Mayo Clinic: PCOS overview

📖 Guideline update: what’s changed in 2023

The 2013 Endocrine Society Guideline is now retired. In 2023, a new International Evidence-Based PCOS Guideline was released, endorsed by the Endocrine Society, ASRM, ESHRE, and others.

Key updates:

• Diagnosis now requires two of three:

  1. Clinical or biochemical androgen excess

  2. Ovulatory dysfunction

  3. Polycystic ovaries on ultrasound or elevated Anti-Mullerian hormone, AMH levels (in adults, AMH can replace ultrasound).

• The guideline recognises PCOS as a lifelong condition with metabolic, reproductive, and psychological implications.

• Care should include screening for metabolic and mental health risks, lifestyle support, and shared decision-making.

Sources:

• 2023 International PCOS Guideline summary – Monash University

• ASRM guideline statement

• European Journal of Endocrinology – Guideline overview

✨ The takeaway

• The exact cause of PCOS is still unknown.

• PCOS isn’t really about cysts — it’s about hormone disruption.

• Excess androgens and insulin resistance drive most of the symptoms, feeding into each other in a cycle.

• The 2023 guideline recognises PCOS as a systemic, lifelong condition.

• Treatments focus on:

  • Improving insulin sensitivity (lifestyle, metformin, inositol).

  • Reducing androgens (hormonal contraceptives, anti-androgens, weight management).

  • Supporting ovulation for fertility.

💬 Final word from TribElle

PCOS is common, complex, and often misunderstood. By breaking the silence and explaining the science, we can give women clarity and confidence. Your symptoms are not your fault. With the right support — clinical care, nutrition, and sometimes medication — PCOS is manageable, and your health and goals are still within reach.

👉 Explore our next blog on evidence-based vitamins for PCOS

👉 Discover nutritional support strategies for PCOS