What is lean PCOS?

7 min
Updated Dec 8th, 2023

Table of contents

Polycystic ovary syndrome (PCOS) varies from woman to woman. As a syndrome, it covers a variety of symptoms, so not all women with PCOS will experience all symptoms and the level of severity will vary. One of these symptoms is weight gain. Losing this excess weight is often the first step in seeking a healthier lifestyle to manage your PCOS. In fact, the first treatment option listed on the NHS website is to lose weight. This can be disheartening and confusing to read if you have PCOS and you’re desperate to relieve some distressing symptoms or boost your fertility but you already have a normal body mass index (BMI). Where do you go from there? We explain what lean PCOS is and how you can make changes to ease your symptoms. 

What is lean PCOS?

Lean PCOS is PCOS in women of normal weight; they make up a small but significant amount of those diagnosed. Weight gain is thought to be a classic PCOS symptom, with the majority of women with PCOS being overweight or obese. This means those with lean PCOS are often slower to be diagnosed. Diagnosing a woman with lean PCOS will be based on the evidence of high androgen levels in the blood and potential issues with the menstrual cycle. An ultrasound scan will be able to find out whether polycystic ovaries are evident.  

What is the difference between lean PCOS and PCOS?

Many PCOS symptoms are evident externally such as acne, weight gain and facial hair. However, some women have very few outward signs of PCOS. Even if this is the case, on the inside of your body, insulin can be causing problems, whether you have lean PCOS or PCOS. 

If you have PCOS and weight gain, then it does help to lose weight. This is because the more weight you gain, the more chance you have of metabolic problems. But there are also problems that both lean PCOS and PCOS sufferers experience. This includes an increased risk of heart disease or diabetes and fertility issues. And with both lean PCOS and PCOS resulting in an increase in androgens, both can suffer from symptoms such as hair loss, unwanted hair growth and acne.  

What are the challenges faced by lean women with PCOS?

Delayed diagnosis

Being obese or overweight affects between 38 and 88% of women with PCOS and so this is why so much advice and support regarding PCOS focuses on women with PCOS who are overweight. But this also means that those women with lean PCOS can receive a delayed diagnosis — often by years. Some women with lean PCOS may not even receive a diagnosis until they start trying for a baby. Unfortunately, undiagnosed PCOS also means that related heart disease and diabetes can be diagnosed later too. 

Insulin resistance

The correlation between PCOS and insulin levels is not fully understood, but we know that being overweight increases your risk of insulin resistance, especially abdominal obesity (where the weight is around your middle). Abdominal obesity is common in those who are obese in general, but it can also appear in women who are a normal weight. However, women with lean PCOS also have an increased risk of insulin resistance even if they’re not overweight in any way. In fact, research has shown that lean women can be insulin-resistant, with one study citing 20–25% of lean women with PCOS exhibiting insulin resistance (those with a BMI of less than 25).

Impaired fertility

Women with PCOS often experience impaired fertility and the first treatment option they’ll be given is to lose weight through diet and exercise to increase their chances of becoming pregnant. One of the reasons for this is that a normal weight gives drugs which can improve ovulation with women with PCOS the best possible chance of working (and therefore improve your chances of conception). One study found that metformin use was more successful in restoring menstruation (55%) and ovulation (45%) in lean women with PCOS compared with those with PCOS who were obese. You can still struggle to conceive with lean PCOS, but being a normal weight is an advantage.

How can you treat lean PCOS?


There are so many benefits to exercising with PCOS — it’s not just about losing weight. Whether you have PCOS or lean PCOS, you can experience low moods and fatigue, regular exercise can help to elevate these symptoms. As you exercise, your body will release endorphins which will make you feel good and give you an energy boost. Cardio such as swimming, jogging, speed-walking or cycling can also increase your insulin sensitivity (halting insulin resistance and preventing pre-diabetes). It can also improve the blood flow to your reproductive organs to aid fertility. Those with lean PCOS can benefit from strength training to help manage PCOS symptoms. Strength training keeps your metabolic rate healthy, lowers androgens and improves insulin resistance.


A PCOS diet and lifestyle can have a huge impact on managing PCOS symptoms successfully and good nutrition plays a big part in this. Not only should your diet be nutritious but you also need to know what to avoid. Carbohydrates can result in your blood sugar rising and then crashing which can make your PCOS symptoms worse. Eating refined sugar and fatty meats can also worsen your symptoms. A diet high in salt is also linked to heart disease so a low-sodium diet will reduce your risk of high blood pressure. But this doesn’t mean going without, you can enjoy plenty of fresh fruit and veg and lots of lean proteins (white fish, tofu, beans for example) and unsaturated fats (like avocados, nuts and seeds).  

Stress management

Stress can be a common PCOS symptom due to the increased production of stress hormones such as cortisol. Elevated stress can lead to higher levels of insulin resistance, so it’s important to treat any feelings of stress or anxiety for the benefit of your physical and mental health. Ensure that you get plenty of sleep (8-10 hours a night) and regular exercise — both will lower your stress levels. You can also try some alternative therapies such as aromatherapy, reflexology or meditation — see what works for you. 

PCOS supplements

As discussed, good nutrition is vitally important whether you have PCOS or lean PCOS. However, it can be difficult to get the right nutrients from diet alone. This is where PCOS supplements can help. Inofolic Alpha combines myo-inositol with alpha lactalbumin (which aids absorption) and this can help with PCOS.

In Summary

Women with lean PCOS can feel as if they are invisible until they receive a long-awaited diagnosis and even then all the PCOS advice provided can be tilted towards those who are overweight. Fortunately, as soon as you’re diagnosed, you can take action: there are many changes you can make to your lifestyle to manage your symptoms and being a healthy weight will benefit you in the long run.


Barber TM, McCarthy MI, Wass JA, et al.  Obesity and polycystic ovary syndrome. Clin Endocrinol (Oxf) 2006.

Marshall JC, Dunaif A. Should all women with PCOS be treated for insulin resistance? Fertil Steril. 2012.

Toosy, Sehar et al. Lean polycystic ovary syndrome (PCOS): an evidence-based practical approach. J Diabetes Metab Disord. Dec 2018.

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