What Causes PCOS? Unpacking the Root Factors

Polycystic Ovary Syndrome (PCOS) is one of the most common hormonal conditions affecting women of reproductive age—but despite how widespread it is, the causes are still not fully understood. What we do know is that PCOS isn’t caused by one single thing. Instead, it results from a combination of hormonal, metabolic, genetic, and even environmental factors.

In this post, we’re diving into the root causes of PCOS to help you understand what might be going on underneath the surface. Whether you’ve just been diagnosed or you’ve known for a while, understanding the “why” behind PCOS can help you make more empowered decisions about how to manage it.

1. Hormonal Imbalances

One of the hallmark features of PCOS is an imbalance in reproductive hormones. Most commonly, women with PCOS have higher-than-normal levels of androgens (often called "male" hormones like testosterone).

These elevated androgens can:

• Disrupt the monthly ovulation cycle

• Prevent the release of eggs (leading to irregular periods)

• Cause symptoms like acne, excess hair growth (hirsutism), and scalp hair thinning

Other hormones often affected in PCOS include:

• LH (Luteinizing Hormone): Often elevated, which may further stimulate androgen production.

• SHBG (Sex Hormone-Binding Globulin): Typically, lower in PCOS, which leaves more free (active) testosterone circulating in the body.

These hormonal shifts create a cycle that makes ovulation irregular and leads to many of the symptoms commonly associated with PCOS.

2. Insulin Resistance

Many women with PCOS (including those who are not overweight) have some degree of insulin resistance. This means the body’s cells aren’t responding well to insulin, a hormone that helps regulate blood sugar.

When the body becomes resistant, it compensates by producing more insulin. This extra insulin can cause the ovaries to produce more androgens (like testosterone), which worsens hormonal imbalance and further disrupts ovulation.

Insulin resistance also:

• Makes it easier to gain weight (especially around the belly)

• Makes it harder to lose weight

• Increases the risk of type 2 diabetes and other metabolic issues

  
  

This is why improving insulin sensitivity through food, movement, and other lifestyle strategies is often a key part of PCOS management.

3. Genetic Factors

PCOS tends to run in families, which suggests a genetic predisposition. While there’s no single "PCOS gene," research suggests that multiple genes may influence your risk.

If your mother, sister, or even aunt has PCOS, your chances of developing it are higher.

That doesn’t mean it’s inevitable—but it does mean your body may be more sensitive to the hormonal or metabolic triggers that lead to PCOS. Knowing your family history can help you be proactive in recognising and managing early signs.

4. Inflammation and Environmental Factors

Chronic, low-grade inflammation is another piece of the puzzle. Women with PCOS often have slightly elevated markers of inflammation, which may trigger the ovaries to produce more androgens.

In addition, lifestyle and environmental exposures can influence how PCOS shows up. Things like:

• A diet high in processed foods or sugar

• Sedentary behaviour

• Exposure to endocrine-disrupting chemicals (like BPA)

  
  

...can all play a role in how strongly PCOS symptoms manifest.

It’s important to remember that obesity does not cause PCOS, but it can make symptoms worse by increasing insulin resistance and inflammation. Conversely, PCOS itself can make weight gain easier, which is why it’s often a frustrating cycle.

PCOS is a multifactorial condition. Hormones, insulin, genes, inflammation, and environment all interact to shape how it presents in your body. That’s why it can look different for every woman.

The good news? Understanding the underlying causes gives us clear starting points for managing symptoms. By addressing things like insulin resistance and inflammation, many women see significant improvements in energy, mood, skin, cycles, and fertility.

In the next blog post, we’ll take a closer look at the wide range of symptoms PCOS can cause—including some lesser-known ones you might not expect.