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I’m a Registered Dietitian dedicated to helping you eliminate your PCOS symptoms with sustainable and realistic nutrition changes.

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PCOS and Fatigue: Why It Happens (And What To Do About It)

If you have PCOS, are you always exhausted? Do you feel like you could take a nap at any hour of the day? If so, trust me, you are not alone. 

I recently did a poll on my Instagram page and the overwhelming majority of people said PCOS fatigue was the worst symptom they struggle with. 

This article will detail the most common reasons why PCOS fatigue happens and some management strategies to combat those low energy levels. 

woman with her head down on a desk.

What Is PCOS?

Polycystic ovary syndrome (PCOS) is a medical condition that affects up to 20% of women of reproductive age. In order to be diagnosed with this common condition, you must have at least 2 of the 3 criterion of the Rotterdam Criteria outlined below: 

  • Anovulatory cycles or irregular periods
  • Polycystic ovaries (fluid-filled sacs) seen on ultrasound 
  • High androgen levels (male hormones such as testosterone)

Symptoms of PCOS

PCOS is commonly associated with insulin resistance, chronic inflammation, high androgen levels, and a variety of PCOS symptoms such as:

  • Hair loss
  • Hirsutism (unwanted and excess hair growth)
  • Acne or oily skin
  • Acanthosis nigricans (dark, velvety skin patches frequently on the neck, armpits, groin, and under the breasts)
  • Irregular periods
  • Weight gain
  • Carb cravings
  • Mood swings 
  • Extreme fatigue

PCOS is also linked to an increased risk of certain chronic diseases such as type 2 diabetes, heart disease or cardiovascular disease, endometrial cancer, nonalcoholic fatty liver disease, and mood disorders. 

Causes of Fatigue with PCOS

It’s easy to blame our busy and chaotic lives for feeling tired all the time, but, if you feel like your exhaustion is next level, it’s probably not just in your head! 

PCOS itself doesn’t cause fatigue. Instead, many of the conditions associated with PCOS can be to blame. 

Since PCOS can present differently in people, what’s causing your fatigue may be different than what’s causing fatigue in your friend with PCOS. Also, you may have multiple factors contributing to your fatigue as well.

Let’s examine a few of the common reasons why people experience fatigue. 

Insulin Resistance

Insulin resistance has been linked to fatigue and it’s very common in PCOS, occurring in approximately 70% of those with PCOS (1, 2). 

With insulin resistance, your body has a harder time moving glucose (aka sugar) out of your bloodstream and into your cells to be used for energy – which means less fuel for your body. 

As a result, your body produces more insulin to compensate, leading to high insulin levels. High insulin levels can lead to weight gain and make weight loss more difficult. 

Insulin resistance also means you’re more likely to have uncontrolled blood sugar levels, which can contribute to feeling more tired (3).

Thyroid Disorders

PCOS can commonly lead to other hormone imbalances, such as an underactive thyroid. 

Your thyroid gland is responsible for producing just the right amount of hormones for your body to function optimally. When your body produces too much thyroid hormone (hyperthyroidism) or not enough thyroid hormones (hypothyroidism), increased tiredness or fatigue is a common symptom (4). 

Hypothyroidism, particularly Hashitmoto’s thyroiditis (an autoimmune disease that can cause hypothyroidism), is a health problem that occurs at a 3x higher rate in those with PCOS (5). 

Mood Disorders: Anxiety & Depression

Research has repeatedly shown that women with PCOS are at an increased risk of mood changes, such as depression and anxiety. These two mental health issues can contribute to fatigue (6, 7). 

Sleep Disturbances

Lack of sleep or sleep disorders is another common feature in PCOS. In a 2017 meta-analysis, the risk of obstructive sleep apnea is almost 10x higher in women with PCOS versus women without PCOS (8). 

Cortisol and melatonin hormonal imbalances can also disrupt your circadian rhythm and cause poor sleep quality. 

Vitamin & Mineral Deficiency

PCOS has been associated with a higher risk of some nutrient deficiencies, which may contribute to fatigue. Some of these nutrients include vitamin D, B vitamins such as vitamin B12, iron, and magnesium

Vitamin D Deficiency

Women with PCOS are at an increased risk of vitamin D deficiency, which may exacerbate tiredness and fatigue. One study showed that 67-85% of women with PCOS have vitamin D deficiency compared to only 20-48% of the general population having a vitamin D deficiency (9). Vitamin D levels can be checked with a simple blood test and should be screened annually. 

Vitamin B12 Deficiency

Fatigue is commonly associated with a vitamin B12 deficiency. It also can be depleted with the use of some common medications used to treat PCOS, such as Metformin and birth control pills (10, 11). Ironically, vitamin B 12 deficiency has also been linked with insulin resistance and obesity (12, 13).Though normal lab ranges can vary, some experts recommend serum vitamin B12 levels to be a minimum of 400 pg/mL. 

Iron Deficiency

Menstrual cycle irregularities are often seen with PCOS. Some women may experience few periods per year, while others experience heavy menstrual bleeding frequently. Heavy bleeding can result in a high volume of blood loss and lead to low iron levels. 

Magnesium Deficiency

Most people do not meet the recommended intake for magnesium, and women with PCOS are no different. 1 in 4 women with PCOS do not meet the magnesium recommended intake amount (14). One study even showed that women with a magnesium deficiency were 19 times more likely to also have PCOS (15).

How to Fix Your PCOS Fatigue

Treatment options may vary based on the root cause of your fatigue. Talk to your doctor about what may be contributing to your low energy levels and having the proper testing done. Your doctor may recommend prescription medications or nutrition supplements to help your symptoms. In addition to this, nutrition and lifestyle changes can be one of the best ways to fight fatigue on a regular basis. 

Eat A Balanced Diet

A healthy diet plays an important role in managing most PCOS symptoms, including fatigue. One of the main goals when it comes to nutrition is to balance blood sugar levels and improve insulin sensitivity. 

Some Key Ways to Improve Insulin Sensitivity: 

  • Eat consistent meals throughout the day. Avoid skipping meals
  • Consider snacks if you have a long stretch of time between meals
  • Combine complex carbohydrates (aka high fiber carbs like whole grains, fruits, veggies, beans, and other legumes) with sources of protein and healthy fats

These small changes in your diet will help to keep blood sugar levels more controlled and give you longer lasting energy. 


Get those fluids in! Most adults don’t get adequate fluids in and even slight dehydration can lead to fatigue. So how much do you need? The U.S. National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake for women is about 11.5 cups (~90 fluid ounces or 2.7 liters) (16).


It may sound counterintuitive, but regular exercise may actually improve energy levels and help to improve sleep at night. Positive results were seen with both low and moderate intensity exercise (17, 18). 


Sleep problems can obviously make fatigue worse so trying to improve your sleep hygiene can be helpful in combating this issue. 

Some things that can help you get more restful sleep:

  • Waking up and going to bed at the same time each night (yep, even on the weekends!)
  • Aim for at least 7 hours of sleep each night
  • Limit or eliminate your screen time before bedtime since it can suppress melatonin production making it more difficult to sleep (19)
  • Getting some exercise in during the day
  • Having a bedtime routine. This can be something simple like a skincare routine, cup of tea, and a guided meditation in the 30 minutes before bed. It helps your brain associate this daily routine with bedtime. 
  • Melatonin or magnesium supplements may be beneficial for some people 

Reduce Stress Levels

One study showed that women with higher stress levels were more likely to report fatigue (20). Chronic stress can increase cortisol levels, our stress hormones. Cortisol is made in the adrenal glands and can wreak havoc on our health. This can also worsen insulin resistance and disrupt sleep. 

Of course, lowering stress levels is easier said than done, but lowering stress levels can be helpful in reducing fatigue and also improving hormone health. 

PCOS Fatigue Key Takeaways

Fatigue is a common complaint with PCOS. 

It can be caused by a variety of reasons such as insulin resistance, thyroid disease, anxiety, depression, sleep issues, and nutritional deficiencies. 

Be sure to talk to your doctor and have proper testing done to confirm or rule out any of these factors.

In addition to treating any medical conditions or deficiencies that may be contributing to your fatigue, things you can do to improve your energy levels include eating a balanced diet, drinking enough fluids, physical activity, getting enough sleep, and reducing stress levels. 

Disclaimer: this is for educational purposes only and not to be construed as medical advice. Always consult with your healthcare provider for a personalized treatment plan based on your individual needs. 

More PCOS Resources You’ll Love

Intermittent Fasting For PCOS: A Dietitian Weighs In

A Dietitian’s 7-Day PCOS Diet Plan (PDF Included)

2 Responses

  1. As far as vitamins go, I’ve been seeing a lot of information about inositol and berberine helping with cellular metabolism and I was wondering if you’d be willing to share your takeaway on those supplements.

    Ps. I love the information you have on your site! I’ve been doing a deep dive and taking notes for the last hour lol. I enjoy the fact that you go into depth about certain topics and often offer substitutions or recommendations for lifestyle swaps. Having PCOS has been discouraging feeling like I’m constantly being told what I shouldn’t eat or drink without very much information or encouragement surrounding substitutions for things I cut out. Thank you very much for sharing what you know and have experienced yourself!

    1. Hi Renee! Thanks so much for your kind words, I’m so glad you’re finding my posts helpful! As far as inositol and berberine, I think they both have big potential as part of a PCOS management approach. That said, whether they’re right for a certain individual will vary since there really isn’t a one-size-fits-all approach to PCOS. I go into a bit of detail on both of them in this post and also compare them to Metformin according to what the research has found.

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