Polycystic ovary syndrome (PCOS) is a common hormonal condition that affects how the ovaries work. The most recognizable PCOS symptoms are irregular or missed periods, excess facial or body hair, acne, and difficulty losing weight, often driven by higher-than-usual levels of androgens ("male" hormones) and insulin resistance. PCOS is treatable but not curable.
What is PCOS?
PCOS is a hormonal and metabolic disorder in which the ovaries may not release eggs regularly and the body produces higher levels of androgens than usual. Despite the name, you do not need to have visible ovarian cysts to have PCOS; the "cysts" are actually small fluid-filled sacs (immature follicles) that can show on an ultrasound.
It is one of the most common causes of irregular periods and reduced fertility in people of reproductive age. According to the World Health Organization, an estimated 10–13% of women globally have PCOS, and around 70% of those affected remain undiagnosed.
PCOS symptoms
Symptoms vary widely from person to person and often begin in the late teens or early 20s. You do not need every symptom to have PCOS. Common signs include:
- Irregular periods — infrequent, prolonged, or absent menstrual periods
- Excess hair growth (hirsutism) — coarse hair on the face, chest, or back
- Acne and oily skin
- Thinning hair or hair loss on the scalp (male-pattern baldness)
- Weight gain or difficulty losing weight
- Difficulty getting pregnant due to irregular ovulation
- Skin changes such as dark, velvety patches (acanthosis nigricans)
PCOS can also affect mental health, with higher rates of anxiety and depression reported. If your periods are unpredictable, it helps to understand the basics first; see our guides on irregular periods and why your period may be late.
What causes PCOS?
The exact cause of PCOS is unknown, but research points to several interacting factors:
- Genetics. PCOS often runs in families. Having a close relative with PCOS or type 2 diabetes raises your risk.
- Excess androgens. Higher levels of androgens interfere with ovulation and drive symptoms like acne and excess hair.
- Insulin resistance. Many people with PCOS have insulin resistance, where the body's cells respond poorly to insulin. The body then makes more insulin, which can increase androgen production. Excess weight can intensify this effect.
These factors can reinforce one another, which is why PCOS affects both reproductive and metabolic health.
How is PCOS diagnosed?
There is no single test for PCOS. A provider typically makes the diagnosis after ruling out other conditions and confirming that at least two of the following three features are present:
- Irregular or absent ovulation (often seen as irregular periods)
- Signs of excess androgens — either physical symptoms or blood test results
- Polycystic ovaries visible on ultrasound
Assessment may include a medical history, physical exam, blood tests for hormones and blood sugar, and a pelvic ultrasound. Because the criteria overlap with conditions like thyroid disorders, professional evaluation is essential.
Managing PCOS
There is currently no cure for PCOS, but symptoms can be managed effectively, often with a combination of approaches tailored to your goals. Treatment is always individualized, so work with your provider.
Lifestyle measures
A balanced diet, regular physical activity, and—where appropriate—gradual weight management are considered foundational. Even modest weight loss can improve insulin sensitivity, regulate cycles, and ease symptoms like excess hair and acne for some people.
Medication
Depending on your needs, a provider may discuss:
- Combined hormonal contraception to regulate periods and reduce androgen-related symptoms (for those not trying to conceive)
- Insulin-sensitizing medication to help the body respond to insulin and support ovulation
- Targeted treatments for acne or excess hair
- Fertility treatment if you are trying to conceive
If you are tracking your cycle to understand ovulation, our guides on ovulation and your fertile window and how to track your menstrual cycle may help you share useful information with your provider.
Long-term health
PCOS is linked to a higher risk of type 2 diabetes, high cholesterol, high blood pressure, and sleep apnea over time. Ongoing care and regular check-ups help monitor and reduce these risks.
PCOS and other period problems
Because PCOS centers on ovulation and hormones, it can be tangled up with other menstrual concerns. If heavy or painful bleeding is part of your picture, it is worth understanding those issues too; PCOS itself is one of several conditions covered in our reproductive and menstrual health hub, alongside related topics like heavy periods.
The bottom line
PCOS is a common, manageable hormonal condition marked by irregular periods, excess androgens, and frequently insulin resistance. Its exact cause is not fully understood, and it cannot be cured, but lifestyle changes and medical care can control symptoms, support fertility, and protect long-term health. If you notice possible PCOS symptoms, see a healthcare provider for an accurate diagnosis and a plan suited to you. This article is general education only and is not a substitute for individualized medical advice.
