What is PCOS? Symptoms, causes and a functional medicine approach

PCOS, now also referred to as polyendocrine metabolic ovarian syndrome (PMOS) following a 2026 international consensus on renaming, is a hormonal condition in which the ovaries produce too much testosterone and other androgens. This interferes with ovulation and produces a wide range of symptoms, many of which have nothing to do with periods or fertility, including skin, weight, mood, and metabolic health.

In Australia, it affects up to one in ten women of reproductive age, and up to 21 per cent of Aboriginal and Torres Strait Islander people. Because symptoms vary so widely, up to 70 per cent of people with PCOS go undiagnosed or receive a partial picture that does not fully explain what is happening in their body.

Why the name changed from PCOS to PMOS

For decades, the name polycystic ovary syndrome pointed to the wrong thing. The “polycystic” in PCOS implied the condition was defined by cysts on the ovaries. In reality, the spots visible on ultrasound are follicles, not cysts, and many people with the condition show no ovarian changes on imaging at all. The name led to missed diagnoses, gaps in care, and a clinical focus that overlooked the metabolic and hormonal complexity of what was actually happening.

The rename followed an eleven-year global consensus process involving over 22,000 patients, researchers, and clinicians across more than 56 organisations, culminating in a paper published in The Lancet in May 2026. The new name was chosen to reflect what the condition actually is. Polyendocrine acknowledges that multiple hormonal systems are involved, not just the ovaries. Metabolic recognises the central role of insulin resistance, weight, cardiovascular risk, and blood glucose. Ovarian keeps the link to ovulatory function and fertility, which remain central to the condition.

In simple terms:

• P is for polyendocrine, meaning multiple hormones are involved
• M is for metabolic, as there’s an increased risk of developing health conditions, like type 2 diabetes and cardiovascular disease, in the long term
• O is for ovarian, as multiple immature follicles (small fluid-filled sacs) in the ovaries can be seen on an ultrasound, but not in everyone
• S is for syndrome, reflecting that multiple symptoms are involved, affecting women’s physical and mental health

Both terms are currently in use. The full transition to PMOS in clinical guidelines, medical education, and disease classification is expected to be complete by 2028. Throughout this article, PCOS and PMOS are used interchangeably to reflect that transition period.

Symptoms of PCOS

The most common symptoms of PCOS are irregular or absent periods, acne, and unwanted hair growth on the face or body, often accompanied by difficulty managing weight, regardless of diet or exercise.

Elevated androgens contribute to most of these symptoms, but insulin resistance compounds them by increasing androgen production further. For many people, mood changes, fatigue, and sleep difficulties are also part of the picture.

Common symptoms include:

• Irregular, infrequent, or absent menstrual cycles or heavy bleeding when periods do occur
• Elevated blood glucose, insulin resistance, high blood pressure, or high cholesterol
• Difficulty losing weight or unexplained weight gain, particularly around the abdomen
• Acne, particularly along the jaw, chin, and chest
• Excess hair on the face, abdomen, or back (hirsutism)
• Thinning of the scalp hair
• Fatigue and low energy
• Low mood, anxiety, or mood instability
• Fertility difficulties related to irregular ovulation
• Sleep disturbance, sometimes related to sleep apnoea
• Many women also experience pain or abdominal discomfort with their period

Not everyone experiences all of these. Some people have a few pronounced symptoms; others have a more subtle presentation. On average, it takes three to five years to receive a diagnosis.

For those who notice symptoms in their teenage years, the overlap with normal puberty can make it harder to identify. Symptoms started early in life may also be masked if oral contraceptives are prescribed before a diagnosis is made.

Despite its name, PCOS does not involve cysts. What appear as dots or spots on ultrasound are follicles containing underdeveloped eggs. Because of this, Australian-led clinical guidelines confirm that ultrasound is not required for diagnosis in adult women. Elevated androgens (hyperandrogenism) and ovulatory dysfunction together are sufficient.

Some people receive a PCOS diagnosis when they have hypothalamic amenorrhoea, a condition where menstruation stops due to disrupted signalling between the brain and ovaries. The two conditions can look similar on ultrasound, but they are clinically distinct: PCOS typically involves elevated androgens and a higher ratio of LH to FSH, two hormones that regulate ovulation, while hypothalamic amenorrhoea presents with low or normal LH, low oestrogen, and no signs of hyperandrogenism. The treatment approach differs considerably as a result.

Listen to Melbourne Functional Medicine practitioner Rebecca Hughes talk about the common signs and symptoms of PCOS below.

What causes PCOS?

The exact cause of PCOS is still debated, but insulin resistance and elevated androgens are the two most consistently identified features, each making the other worse.

Insulin resistance causes the body to produce higher levels of insulin, which then signals the ovaries to produce more testosterone than they should. Up to 70 per cent of people with PCOS experience some degree of insulin resistance, and people with PCOS face a significantly higher risk of developing type 2 diabetes, particularly before the age of 40. Importantly, insulin resistance is present even in people with PCOS who are not overweight; weight alone does not determine whether it develops.

This rise in testosterone interferes with normal follicle development. Eggs begin to mature but do not release as they should, leaving multiple small follicles on the ovaries, which is what an ultrasound often detects.

Genetics also play a role. Studies find PCOS in around 35 to 40 per cent of close female relatives of people with the condition, and it is more than twice as prevalent among Aboriginal and Torres Strait Islander women. Genetics increase the likelihood of developing PCOS, but diet, movement, stress, sleep, gut health, and ongoing inflammation all affect how severely symptoms develop.

Thyroid function and the stress response both affect how PCOS presents. An underactive thyroid can worsen insulin resistance and make cycles more irregular. Chronic stress raises cortisol, which signals the adrenal glands to produce more androgens, adding to what the ovaries are already producing. An underactive thyroid can worsen insulin resistance and hormonal irregularity.

Gut health is also emerging as a contributing factor. Research using genetic analysis methods has found evidence that the mix of bacteria in the gut may influence PCOS risk rather than simply being affected by it.

Complications of PCOS

Without active management, PCOS raises the risk of several serious conditions over the longer term, including type 2 diabetes, heart disease, and endometrial cancer. People with PCOS are around three times more likely to develop high blood pressure and have a significantly elevated risk of cardiovascular events, including coronary artery disease, heart attack, and stroke. The risk of type 2 diabetes is also substantially higher, with more than half of people with PCOS developing it by age 40. Endometrial cancer risk is increased because irregular or absent ovulation means the uterine lining is not shed regularly, meaning the uterine lining thickens rather than being shed, which raises the risk of endometrial cancer.

Liver health is an area that receives less attention but is clinically relevant. A meta-analysis of 23 studies found that people with PCOS have more than twice the risk of a condition called non-alcoholic fatty liver disease, where fat builds up in the liver unrelated to alcohol, linked to the combination of insulin resistance and elevated androgens. Mental health is also affected. People with PCOS have a 30 per cent higher likelihood of clinically significant anxiety and over 15 per cent higher likelihood of depression, independent of other factors. Addressing the metabolic picture early reduces risk across all of these areas.

How is PCOS diagnosed and assessed?

In Australia, PCOS diagnosis typically begins with a GP, using clinical criteria, blood results, and sometimes imaging.

Current Australian guidelines apply the Rotterdam criteria, which require at least two of the following three to be present:

• Irregular or absent ovulation
• Elevated androgens, either on bloodwork or through clinical signs such as acne or hirsutism
• Polycystic-appearing ovaries on ultrasound

Ultrasound is not required for diagnosis in adult women. If the first two criteria are met, that is sufficient.

Standard blood testing typically includes:

• Testosterone and other androgens
• LH and FSH
• Anti-Mullerian Hormone
• Thyroid hormones
• Fasting glucose and insulin
• Sometimes prolactin, to rule out other causes of cycle irregularity

One limitation of standard assessment is that PCOS is sometimes confused with hypothalamic amenorrhoea, a condition where menstruation stops due to low energy availability or significant stress affecting communication between the brain and ovaries. Ovarian appearance on ultrasound can be similar in both, but distinguishing features include the LH:FSH ratio, oestrogen levels, and whether androgens are elevated. The causes and appropriate responses differ considerably.

A functional assessment looks at what is contributing to your symptoms specifically, examining insulin levels, adrenal hormones, thyroid function, and inflammation together, rather than testing each one and treating it separately.

Fasting insulin is particularly important. A standard fasting glucose test can miss this; insulin may be significantly elevated even when glucose looks normal. A person can have normal glucose but significantly elevated insulin, indicating the pancreas is working harder than it should to keep blood sugar stable.

Functional testing may include:

• Advanced hormone profile: measures testosterone and other androgens, DHEA, LH, FSH, and oestrogen to identify which androgens are elevated, whether ovulation is occurring regularly, and how the LH to FSH ratio is presenting
• Advanced thyroid panel: free T3, free T4, and thyroid antibodies alongside TSH, given that low thyroid function can produce symptoms that closely overlap with PCOS and worsen insulin sensitivity
• Blood glucose and insulin monitoring: fasting insulin, glucose, and HbA1c, and HOMA-IR to identify insulin resistance and assess how significantly it may be contributing to androgen production and cycle irregularity
• Nutrient deficiency testing: vitamin D, magnesium, zinc, and iodine, which are commonly low in PCOS and don’t always correct with diet change alone
• Additional assessment where relevant: inflammatory markers, full lipid panel, cortisol and adrenal hormones where stress is a prominent feature, and gut microbiome assessment where digestive symptoms or significant inflammation are present

Why PCOS symptoms often persist after treatment

PCOS symptoms often persist because conventional treatments target individual symptoms, including cycles, fertility, skin, weight, and mood, without changing the metabolic conditions producing them.

Conventional treatments include:

• Combined oral contraceptive pill, to regulate cycles and reduce androgen effects
• Metformin, an insulin-sensitising medication used to manage blood glucose and insulin resistance
• Letrozole, considered first-line treatment for ovulation induction, replacing clomiphene citrate as the preferred option due to better outcomes and lower risk of multiple pregnancies
• Anti-androgens, used as second-line agents for people who have not responded to first-line ovulation induction
• Hormone injections (gonadotrophins), used as second-line therapy for infertility related to absent or irregular ovulation where oral treatments have not been effective
• Laparoscopic ovarian drilling, a minor surgical procedure, a second-line option for people who have not responded to oral ovulation induction
• Weight loss medications such as GLP-1, which can improve symptoms in people where insulin resistance is contributing to weight gain
• Antidepressants and anti-anxiety medications, given that people with PCOS experience higher rates of depression and anxiety
• Acne treatments, including pharmaceutical and topical options for PCOS-associated acne

The oral contraceptive pill regulates cycles and reduces androgen effects while it is being taken. When it is stopped, cycles and symptoms often return as they were, because the insulin resistance and androgen output have not changed. The pill works by overriding the body’s hormonal cycle, not by correcting what was producing the problem.

Metformin can reduce androgen production and support more regular cycles by improving insulin sensitivity. But if the dietary patterns, activity levels, sleep quality, and stress that maintain insulin resistance remain unchanged, the condition continues regardless.

For many people, symptoms ease during periods of reduced stress, better sleep, and consistent movement, then return when those conditions change. This pattern reflects how responsive PCOS is to what is happening at a whole-body level, and points to why addressing those contributors directly often produces more lasting change.

Treating PCOS: a functional medicine approach

A functional medicine approach to PCOS begins with a question that standard care often doesn’t ask: what is actually producing your symptoms, and why?

For most people, that means looking closely at insulin resistance, thyroid function, adrenal hormones, gut health, and inflammation, not as separate problems, but as part of the same picture. The goal is to address what is producing your symptoms directly, rather than managing each one as it appears.

Depending on your presentation, treatment may include:

• Insulin and metabolic support: Diet and exercise changes that reduce your body’s need for insulin, which may help lower androgen levels and support more regular cycles
• Nutritional support: Nutrients such as inositol, magnesium, and berberine may help regulate your blood glucose and insulin sensitivity alongside dietary change
• Herbal medicine: Herbal medicine may help regulate the androgen levels behind acne, excess hair growth, or cycle irregularity
• Thyroid assessment: Thyroid function is checked alongside your reproductive hormones, since low thyroid function can worsen PCOS symptoms
• Stress and nervous system support: Addressing cortisol and stress may ease the androgen and cycle changes that diet alone doesn’t resolve
• Sleep quality: Improving sleep may help lower cortisol and support healthier blood glucose and androgen levels
• Gut health: Supporting your gut microbiome may help with oestrogen clearance and inflammation, both linked to PCOS symptoms

When to seek support

PCOS is a long-term condition, and getting a thorough assessment early makes it easier to understand what’s contributing to your symptoms, support fertility, and reduce the risk of complications, including type 2 diabetes and cardiovascular disease.

See a practitioner if:

• Your periods are consistently irregular, absent, or unpredictable
• You have been managing symptoms with the pill and want to understand what is happening underneath
• You are planning a pregnancy or having difficulty conceiving
• You have persistent acne, unwanted hair growth, or scalp hair thinning that has not responded to standard treatment
• You are experiencing significant mood changes, fatigue, or unexplained weight changes
• You have been diagnosed with PCOS but have not had a metabolic assessment including fasting insulin

Frequently asked questions

What is the difference between PCOS and PMOS?

PMOS (polyendocrine metabolic ovarian syndrome) is the new name for PCOS, adopted through a 2026 international consensus process led by researchers at Monash University. The name change reflects that the condition involves hormonal, metabolic, and reproductive systems together, not ovarian cysts. Diagnosis criteria remain the same.

Can you get pregnant with PCOS?

Yes. PCOS affects ovulation, which can make conception harder, but many people with the condition conceive naturally or with support. Irregular ovulation is the primary fertility barrier, and addressing insulin resistance through diet, movement, and targeted nutritional support can improve cycle regularity and ovulation without medication in some cases.

Is the pill the best treatment for PCOS?

The oral contraceptive pill reduces androgen effects and regulates cycles while it is being taken, but it does not address insulin resistance or the hormonal contributors producing the condition. Whether it is the right choice depends on a person’s symptoms, goals, and overall picture.

What is the best diet for PCOS?

A low-GI diet built around whole foods is the most consistently supported dietary approach for PCOS. It reduces the body’s demand for insulin, which can lower androgen levels and support more regular cycles. Reducing processed carbohydrates, sugar, and inflammatory foods, while prioritising protein and fibre, produces the most consistent results.

Does PCOS cause weight gain, or does weight gain cause PCOS?

The relationship runs in both directions. Insulin resistance, present in the majority of people with PCOS, promotes fat storage around the abdomen and makes weight loss harder. Excess body fat also affects hormone production, which can make symptoms worse. Addressing insulin sensitivity directly tends to be more effective than weight loss alone.

Does PCOS go away on its own?

PCOS does not resolve without active management, but symptoms can improve significantly with dietary change, movement, and support for the underlying metabolic picture. For some people, cycle regularity improves, and androgen symptoms ease considerably. The metabolic underpinnings, particularly insulin resistance, remain without targeted intervention.

What blood tests are most useful for PCOS?

Fasting insulin is the most informative test beyond the standard reproductive hormone panel. Many people with PCOS have normal fasting glucose but significantly elevated insulin, meaning standard metabolic screening misses insulin resistance entirely. Anti-Mullerian Hormone AMH and a comprehensive thyroid panel including free T3 and T4 add useful context depending on how the condition is presenting.

Can PCOS improve after menopause?

Cycle irregularity resolves after menopause because ovulation stops. The metabolic aspects, particularly insulin resistance and the associated cardiovascular risks, do not disappear. The risk of type 2 diabetes and cardiovascular disease remains elevated, which is why addressing the metabolic picture matters at any age.