PMOS (formerly PCOS): What It Really Is, What Causes It & How to Actually Address It

If you've been told you have PMOS (formerly PCOS) — or if you suspect you might — you've probably left a doctor's appointment with more questions than answers. Maybe you were handed a birth control prescription and sent on your way. Maybe you were told to "lose weight" without any real guidance. Or maybe you got a diagnosis that felt more like a life sentence than a starting point.

I want to change that. PMOS (formerly PCOS) is the most common endocrine and metabolic disorder in women of reproductive age, affecting somewhere between 8 and 13 percent of the global female population — yet it remains one of the most misunderstood and under-addressed conditions in women's health. In May 2026, The Lancet published a formal consensus renaming the condition from Polycystic Ovary Syndrome (PCOS) to Polyendocrine Metabolic Ovarian Syndrome (PMOS), a name that better reflects its true nature. After working with thousands of women over the past two decades, I've seen first-hand how much is possible when you understand what's truly driving PMOS.

This article covers what PMOS actually is, how it's diagnosed, what's driving it at a root cause level, and — most importantly — where to start addressing it.

What PMOS (formerly PCOS) Actually Is

Let's start with the name itself, because "Polycystic Ovary Syndrome" was genuinely misleading — which is exactly why it was officially renamed. In May 2026, The Lancet published a formal consensus renaming it to Polyendocrine Metabolic Ovarian Syndrome (PMOS), a name that better captures the condition's true nature. Despite its former name, PMOS is not actually a condition defined by cysts on the ovaries. In fact, approximately 20 percent of women who don't have PMOS have cysts on their ovaries — and about 30 percent of women who do have PMOS don't have visible cysts at all.

What those "cysts" actually are is a collection of antral follicles — small immature follicles that haven't completed the maturation process needed to trigger ovulation. They're not truly cysts at all. The new name, PMOS, reflects what the condition actually involves: disruption across the endocrine and metabolic systems, centred on the ovaries.

PMOS is not a single condition with a single cause. It's a syndrome — a collection of symptoms that can have different underlying drivers and can present very differently from one person to the next. This is exactly why it's so tricky to diagnose and why a one-size-fits-all treatment approach rarely works.

How It's Diagnosed

Because PMOS (formerly PCOS) presents so differently from person to person, the medical community established the Rotterdam Criteria to standardise diagnosis. Under these criteria, a person needs to meet at least two out of three of the following:

• •Oligoovulation or anovulation — irregular, infrequent, or absent ovulation
• •Hyperandrogenism — clinically elevated androgens or symptoms of androgen excess (acne, hirsutism, hair thinning)
• •Polycystic ovaries — enlarged ovaries with 12 or more small follicles on ultrasound

From there, four PMOS phenotypes have been defined: Phenotype A (all three criteria), Phenotype B (ovulatory dysfunction + hyperandrogenism), Phenotype C (hyperandrogenism + polycystic ovaries with regular ovulation), and Phenotype D (ovulatory dysfunction + polycystic ovaries without hyperandrogenism).

Crucially, PMOS is a diagnosis of exclusion. Your doctor should rule out congenital adrenal hyperplasia, hypothyroidism, elevated prolactin, and hypothalamic amenorrhea before landing on a PMOS diagnosis — because the approach to each is very different.

Symptoms to Know

The symptoms of PMOS (formerly PCOS) are largely driven by excess androgens, disrupted ovulation, and the downstream effects on other hormones. Here's what to look out for:

Signs of androgen excess

• •Excess facial or body hair (hirsutism) — especially on the chin, upper lip, chest, or abdomen
• •Acne, particularly on the chin, jaw, or back
• •Male-pattern hair thinning or loss on the scalp
• •Increased body odour and irritability or aggression

Cycle and ovulation symptoms

• •Irregular periods — cycles longer than 35 days, unpredictable, or absent altogether
• •Very light or very heavy periods
• •Difficulty getting pregnant

Metabolic symptoms

• •Unexplained weight gain, especially around the midsection
• •Difficulty losing weight despite diet and exercise
• •Intense sugar or carbohydrate cravings and energy crashes after meals
• •Skin tags or darkening of skin in body folds (acanthosis nigricans)

The Full Hormone Picture

PMOS (formerly PCOS) doesn't just affect one hormone — it creates a cascading disruption across the entire hormonal system. Understanding this is key to knowing where to intervene.

Insulin: the lynchpin hormone

In most cases, the most important hormone to understand in PMOS is insulin. Insulin resistance affects approximately 65–70% of people with PMOS, even those who aren't overweight. High insulin stimulates excess androgen production, reduces SHBG (the protein that keeps testosterone bound and inactive), and disrupts the feedback loop that governs ovulation.

Androgens

Androgen excess — elevated testosterone, DHT, androstenedione, and/or DHEA — is the hallmark of PMOS. About 20–30% of people with PMOS also have elevated adrenal androgens, particularly DHEA-S, linked to chronic stress and HPA axis dysregulation.

Estrogen and progesterone

Women with PMOS often don't have high estrogen. Because ovulation doesn't happen reliably, progesterone — produced after ovulation — stays chronically low. This creates a state of relative estrogen dominance, contributing to bloating, breast tenderness, and heavy periods.

FSH, LH, and AMH

In PMOS, disrupted GnRH signalling raises LH levels relative to FSH. Without enough FSH to properly prepare follicles, you end up with a collection of half-developed follicles on the ovaries — the "polycystic" appearance — instead of one dominant follicle reaching ovulation.

The Root Causes

To truly address PMOS (formerly PCOS), you need to understand the why behind the hormonal picture. Here are the five main root cause areas:

1. Blood sugar and insulin dysregulation

The modern diet — high in refined carbohydrates, ultra-processed foods, and sugar — is tailor-made to disrupt insulin signalling. Chronic stress also drives up cortisol, which raises blood sugar further. Addressing blood sugar regulation is often the single most effective lever for improving PMOS symptoms.

2. Chronic inflammation

PMOS is fundamentally an inflammatory condition. Research has found elevated inflammatory markers in women with PMOS regardless of weight or body composition. Key drivers include high sugar intake, gut dysbiosis, environmental toxins, and unmanaged chronic stress.

3. Gut health and microbiome disruption

Emerging research shows significant microbiome differences in women with PMOS. The gut "estrobolome" influences estrogen metabolism and clearance — a disrupted microbiome interferes with this, contributing to the hormonal imbalances we see. Healing the gut is a central part of addressing PMOS at the root.

4. HPA axis dysregulation (chronic stress)

In people with PMOS, altered cortisol metabolism over-stimulates the adrenals, driving production of adrenal androgens (primarily DHEA-S) that add to the androgen burden. Chronic low blood sugar also triggers cortisol release — creating a frustrating feedback loop.

5. Environmental toxins and endocrine disruptors

Endocrine-disrupting chemicals (EDCs) found in plastics, pesticides, and personal care products can mimic or interfere with hormones. Research has found elevated levels of BPA and phthalates in women with PMOS, worsening insulin resistance and androgen production.

Where to Start

Step 1: Address blood sugar regulation

• •Eat balanced meals built around protein, healthy fats, and fibre-rich complex carbohydrates
• •Eliminate or significantly reduce refined sugar, ultra-processed foods, and refined grains
• •Consider supplements supporting insulin sensitivity: myo-inositol, berberine, magnesium, chromium, and alpha-lipoic acid all have PMOS-specific research
• •Move your body regularly — even walking after meals significantly improves insulin sensitivity

Step 2: Heal the gut

• •Prioritise a diverse, fibre-rich diet to support a healthy microbiome
• •Consider a quality probiotic with strains like Lactobacillus rhamnosus and Bifidobacterium longum
• •Address underlying gut conditions — SIBO, dysbiosis, and intestinal permeability are common in PMOS

Step 3: Support your nervous system

• •Build consistent stress management practices — breathwork, gentle yoga, and vagal toning exercises
• •Prioritise sleep: poor sleep worsens insulin resistance and drives up cortisol and androgen levels
• •Consider adaptogenic herbs like ashwagandha and rhodiola for HPA axis support

Step 4: Reduce toxin exposure

• •Transition to glass or stainless steel food storage; avoid microwaving food in plastic
• •Choose organic for the most pesticide-heavy crops (the "Dirty Dozen" list is a good guide)
• •Audit your personal care and cleaning products and switch to low-toxin alternatives

Getting the Right Support

PMOS (formerly PCOS) often requires a collaborative approach. While diet and lifestyle interventions are the foundation, many women will also benefit from working with a functional medicine doctor or naturopath who can order comprehensive hormone testing (insulin, androgens, DUTCH hormone metabolites, thyroid, and inflammatory markers).

The most important thing I want you to take away from this article: PMOS is not your destiny. The research is clear that dietary and lifestyle interventions can significantly reduce the hormonal and metabolic features of PMOS. Women do restore regular cycles. Women do get pregnant. Women do see their acne, hair growth, and weight challenges resolve. It takes commitment and the right support — but it is absolutely possible.