Irregular periods. Chin hairs that seem to multiply overnight. Acne you thought you'd left behind in high school. Hair thinning in places you'd very much like it to stay.
On their own, these things can have many explanations. Together, they can sometimes point to PMOS—polyendocrine metabolic ovarian syndrome, formerly known as PCOS.
PMOS affects approximately one in eight women, yet getting a diagnosis isn't always straightforward. That's partly because PMOS doesn't look the same for everyone—and despite what its former name suggested, you don't need ovarian cysts to have it.
So, what should you actually be looking for?
Here are five signs associated with PMOS—and what they might be telling you.
New to PMOS? Start with our complete guide to PMOS (formerly PCOS), including what it is, what causes it and how it's diagnosed.
1. Irregular or infrequent periods
One of the most recognizable signs of PMOS is a menstrual cycle that doesn't exactly respect your calendar.
That might mean:
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cycles that are unusually long
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fewer periods throughout the year
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periods that disappear for months
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cycles that vary considerably in length
The reason often comes down to ovulatory dysfunction. PMOS can interfere with regular ovulation, which in turn affects when—and whether—you get a period.
Irregular cycles are also one of the key features healthcare providers consider when assessing someone for PMOS.
That doesn't mean one late period equals PMOS. Menstrual cycles can change for plenty of reasons. It's a pattern of irregular or infrequent cycles that deserves attention.
And yes, it's possible to have PMOS and relatively regular periods. The international guideline notes that ovulatory dysfunction can occur even with regular cycles.
Read: PMOS and Your Period: What to Expect With an Unpredictable Cycle
2. Excess facial or body hair
If you're suddenly spending significantly more quality time with your tweezers, PMOS could be one possible reason.
Hirsutism is excessive coarse or dark hair growth in areas where hair growth is typically influenced by androgens. That can include the face, chin, neck, chest, abdomen, back or thighs.
PMOS is associated with hyperandrogenism, meaning higher levels or effects of androgens such as testosterone.
And hirsutism isn't merely cosmetic. In adults, the current international PMOS guideline says the presence of hirsutism alone should be considered predictive of biochemical hyperandrogenism and PMOS. It also emphasizes that self-reported unwanted excess hair growth matters, regardless of how clinically severe it appears.
In other words: if it's significant to you, it's significant enough to mention to your healthcare provider.
3. Persistent acne
Hormonal acne isn't exclusive to PMOS, but it can be another piece of the picture.
Higher androgen activity can contribute to increased oil production and acne, particularly when acne is persistent or appears alongside other PMOS features.
There's an important caveat here, though: acne on its own isn't a particularly strong predictor of PMOS. The international guideline specifically notes that acne without hirsutism is a relatively weak predictor of biochemical hyperandrogenism.
That's an important distinction because having acne doesn't mean you have PMOS.
But acne plus irregular periods, excess hair growth or other signs?
That's useful information to bring to your healthcare provider.
4. Thinning hair on your scalp
Here's one of the particularly unfair tricks androgen activity can play:
More hair where you don't necessarily want it. Less where you do.
Female-pattern hair loss or noticeable scalp hair thinning can occur with PMOS and is another potential sign of clinical hyperandrogenism.
You might notice a widening part, reduced hair density or gradual thinning, particularly around the crown.
Like acne, hair thinning by itself isn't a strong predictor of biochemical hyperandrogenism, so it shouldn't be treated as proof of PMOS.
But if you're noticing changes to your hair alongside menstrual irregularities, hirsutism or other symptoms, it's worth mentioning the whole picture rather than treating each symptom as an unrelated problem.
5. Signs of insulin resistance or metabolic changes
This is where our understanding of the condition has expanded considerably—and one reason metabolic is now right there in its name.
Insulin resistance is an important feature of PMOS, and people with the condition have an increased risk of impaired glucose tolerance and type 2 diabetes regardless of age and BMI. Current guidelines recommend assessing glycemic status when PMOS is diagnosed and periodically thereafter based on individual risk factors.
Some people with PMOS experience weight gain or find weight management difficult, but this needs a giant asterisk:
You do not have to live in a larger body to have PMOS.
PMOS occurs across body sizes, and body weight isn't a diagnostic criterion.
That's important because focusing too heavily on weight can mean symptoms in people with lower BMIs are overlooked—and can contribute to weight stigma for people in larger bodies. The international guideline explicitly calls for healthcare professionals to recognize and minimize weight stigma in PMOS care.
So rather than treating weight gain as the metabolic sign of PMOS, it's more accurate to understand metabolic health as one part of a much bigger picture.
What about painful or heavy periods?
This deserves its own mention because painful periods appeared on our original version of this list.
Period pain can absolutely be real, severe and worthy of medical attention.
But severe period pain isn't considered a defining diagnostic feature of PMOS, so we don't think it's accurate to include it among the five primary signs.
Heavy or irregular bleeding can occur alongside ovulatory dysfunction, but significant pelvic or menstrual pain can also be associated with other conditions.
Translation: don't assume terrible period pain is “just PMOS.”
If you're experiencing severe or worsening pelvic pain, very heavy bleeding or symptoms that interfere with your daily life, talk to a healthcare provider about what's happening.
Other symptoms and health concerns associated with PMOS
The five signs above aren't an exhaustive PMOS checklist.
PMOS is a multisystem condition and is associated with reproductive, metabolic and psychological health concerns. People with PMOS can also experience fertility challenges related to irregular ovulation, sleep concerns and reduced quality of life. Anxiety and depression are also more prevalent in people with PMOS, and current guidelines recommend healthcare professionals screen for both.
That's part of why the 2026 change from polycystic ovary syndrome (PCOS) to polyendocrine metabolic ovarian syndrome (PMOS) matters.
The condition was always bigger than the ovaries.
Now the name finally reflects it.
PCOS Is Now PMOS: What the New Name Means and Why It Matters
How do you know if you have PMOS?
Here's what not to do: count how many symptoms you have and diagnose yourself from an internet checklist.
We know. Slightly ironic coming from an article with a numbered list.
But these signs are meant to help you recognize when it might be worth having a conversation with a healthcare professional—not diagnose PMOS yourself.
In adults, PMOS is generally diagnosed when at least two of three features are present after other potential causes have been excluded:
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ovulatory dysfunction
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clinical or biochemical hyperandrogenism
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polycystic ovarian morphology, assessed through ultrasound or, in adults, AMH as an alternative for defining ovarian morphology
If irregular cycles and hyperandrogenism are already present, an ultrasound or AMH isn't necessarily required for diagnosis. Diagnostic criteria are different for adolescents.
And despite the condition's former name, you do not need ovarian cysts to be diagnosed with PMOS.
Learn more in What Is PMOS (Formerly PCOS)? Symptoms, Diagnosis and What to Know.
Think you might have PMOS? Start with the whole picture.
If several things in this article sound familiar, consider keeping track of what you're experiencing before talking with your healthcare provider.
Your menstrual cycle is useful information, but don't stop there. Changes in facial or body hair, acne, scalp hair, metabolic health and family history can all help build a fuller picture.
And don't dismiss something simply because it seems cosmetic.
Periods, chin hair, acne and thinning hair can feel like four completely unrelated complaints.
Sometimes they're not.
That's the point of recognizing the signs.
Originally published September 10, 2024. Fully updated September 4, 2026 to reflect current PMOS terminology and guidance.
Resources:
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International Evidence-Based Guideline for the Assessment and Management of PMOS — Monash University
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Recommendations from the 2023 International Evidence-Based Guideline