All about PCOS
Understanding PCOS, system by system.
Polycystic ovary syndrome (PCOS) touches far more than the ovaries. This page walks through what PCOS is, how it affects metabolism (the way your body turns food into energy), and what current research says about nutrition, supplements, exercise, and mindset, all gathered in one place for easy reference.
PCOS shows up across four connected systems in the body
What is PCOS?
Polycystic ovary syndrome is the most common hormonal condition (a condition caused by an imbalance of the body's chemical messengers) in women of reproductive age. It affects an estimated 4 to 20 percent of women, depending on the population studied[1]. Its exact cause is still not fully understood, and it is considered a complex, whole body syndrome rather than a single, simple diagnosis.
- Ovulation that is irregular or absent (this is called anovulation, meaning an egg is not released during a cycle)
- Signs of higher than typical androgen levels (androgens are hormones such as testosterone), noticed either by a doctor or through a blood test
- Ovaries that show a polycystic pattern on an ultrasound scan, meaning many small, fluid filled sacs called follicles
This checklist is known as the Rotterdam criteria, the most widely used framework doctors use to diagnose PCOS[2]. A diagnosis requires meeting two of these three signs, which is why PCOS can look quite different from one person to the next.
Because PCOS is diagnosed through a combination of signs rather than one single test, two people can both have PCOS while experiencing almost entirely different symptoms. One might struggle mainly with irregular cycles, another mainly with acne and extra hair growth, another with weight and blood sugar. Care should reflect that individuality.
PCOS is more than a reproductive condition
Research groups PCOS symptoms into four broad categories[3]. Most people notice symptoms from more than one at the same time.
Cycles and fertility
- Irregular periods
- Anovulation (cycles where an egg is not released)
- Reduced fertility and higher risk of pregnancy complications
Blood sugar and heart health
- Insulin resistance (explained below)
- Higher risk of type 2 diabetes, cardiovascular disease (heart and blood vessel disease), and fatty liver
- Dyslipidemia, meaning an imbalance in blood cholesterol and fats
Mood and wellbeing
- Higher rates of anxiety and depression
- Reduced quality of life
- Effects on body image and self worth
Skin and hair (dermatological simply means related to the skin)
- Hirsutism, meaning extra hair growth on the face or body
- Acne and seborrhea (oily, flaky skin)
- Alopecia, meaning thinning hair on the scalp
These systems interact with each other. Insulin resistance can raise androgen levels, which can worsen both cycle regularity and skin or hair symptoms, while the day to day experience of managing all of it can affect mood and quality of life. That is part of why fixing just one symptom rarely tells the whole story.
Insulin, appetite, and the "slow metabolism" myth
Metabolic changes sit at the center of PCOS for many people. Here is what the evidence actually shows.
Insulin resistance
Insulin is the hormone that helps move sugar out of the blood and into your cells for energy. Insulin resistance means the body's cells do not respond well to insulin, so the body has to make more of it. This is a key driver for many people with PCOS, though not everyone with PCOS is insulin resistant[5]. Even after accounting for body weight and age, insulin resistance tends to run higher in people with PCOS than in the general population[4]. It is linked to a chain reaction: higher insulin can raise the activity of an enzyme called 5 alpha reductase (an enzyme is simply a protein that speeds up a chemical reaction in the body), which increases androgen activity, one route toward symptoms like extra hair growth.
Is BMR really lower?
BMR stands for basal metabolic rate, the number of calories your body burns just to keep itself running at rest. A belief that has been around for a while is that BMR is meaningfully reduced in PCOS, making weight management inherently harder[6]. That belief rests almost entirely on one study, and a closer look at the wider research does not support a large, blanket reduction in BMR across everyone with PCOS[7]. See the charts below.
Appetite regulation
The hormones that control hunger and fullness can work differently in PCOS. For example, some studies show a weaker feeling of fullness after meals[9] and altered patterns of ghrelin (a hormone that triggers hunger), particularly alongside higher testosterone and insulin resistance[8]. This may make hunger and fullness cues feel less reliable, which is worth naming rather than dismissing.
Where the "lower metabolism" claim comes from
A single, widely shared 2009 study measured resting calorie burn (BMR) in 91 women with PCOS and 48 women without it, and reported a large gap, especially in women with PCOS and insulin resistance. The chart below is rebuilt from the numbers that study reported. It is not a copy of the study's own published figure, just the same data redrawn[6].
(control group)
resistance
resistance
Calories burned at rest per day (adjusted BMR, kcal/day), as reported in Georgopoulos et al., 2009[6].
How that study compares to everyone else's
Seven controlled studies, side by side
A 2024 review found every controlled study that has directly measured BMR in both women with PCOS and women without it, using a reliable method (7 studies, 444 people total), then compared how far apart the two groups were in each one. Bars to the left mean PCOS came out lower, bars to the right mean PCOS came out slightly higher. Georgopoulos stands alone[7].
Difference in BMR between the PCOS group and the non-PCOS group in each study (positive means the PCOS group had a slightly higher average). Data from the 7 study meta-analysis in Peele and Nuckols, 2024[7]. Pooled across all seven studies, the average difference was not statistically meaningful. With Georgopoulos removed, the remaining six studies leaned slightly toward PCOS having marginally higher, not lower, BMR, though that difference was also trivial.
Looking closely at that one study, several specific issues stand out[7]:
- 1An unvalidated device. BMR was measured with a calorimeter model that has no independent research confirming its accuracy. A higher end version from the same manufacturer, when tested elsewhere, turned out to be far less reliable than the standard devices most labs use.
- 2Statistically flagged as an outlier. In the 2024 meta-analysis, this study's result was mathematically identified as unusually influential compared with the other six, several times larger than any of the checks used to catch odd data points.
- 3Implausibly wide spread in the results. The variation reported around the average BMR was around three times larger than what similar studies typically report, which is a common sign that something went wrong in measurement or data entry rather than reflecting real biological variation.
- 4Physically impossible values in a related study. A separate study from the same research group, using the same equipment, reported individual BMR values that fall outside the range seen anywhere else in adult metabolic research, even in severe illness.
None of this means the researchers acted in bad faith. It is far more likely a case of imperfect equipment producing noisy data that looked like a meaningful pattern, then getting cited widely before anyone checked the device or the wider literature.
Visceral fat is fat stored deep around your internal organs, rather than just under the skin. Several studies find higher visceral fat in women with PCOS compared to others of a similar weight, even at a similar BMI (body mass index, a simple measure that uses height and weight) in leaner individuals[10]. Visceral fat is closely tied to the androgen and insulin resistance picture, which is one reason body composition can matter more than the number on the scale alone.
Food based strategies with the strongest support
There is no single "PCOS diet." But a few consistent themes show up across the research.
Weight loss (where appropriate)
For those in a larger body, even a modest 5 to 10 percent reduction in weight is associated with meaningful improvements across reproductive, metabolic, and psychological markers, including cycle regularity and fertility[13], insulin sensitivity[11], hormone levels[12], cholesterol and blood pressure[14], and quality of life[15]. It is generally framed as a reasonable first step rather than the only option[16]. For those in a lean body with PCOS, research more often points toward maintaining weight while focusing on food quality and exercise, rather than trying to lose weight.
Lower GI and GL, higher fibre
GI stands for glycemic index and GL stands for glycemic load, both measures of how quickly a food raises your blood sugar. Eating patterns that are lower in GI and GL show small but consistent benefits for PCOS, likely by supporting steadier blood sugar and insulin levels. Lower carbohydrate does not need to mean very low carbohydrate or ketogenic (a diet very low in carbohydrates). Sticking with a pattern matters more than any specific number, and a pattern someone can maintain will usually work better than a stricter one they cannot.
Moderate to high protein
Higher protein intake may help offset a tendency toward increased muscle protein breakdown seen overnight in some PCOS research[18], and can support fullness and lean muscle, even outside of a calorie deficit (eating fewer calories than your body uses).
Anti inflammatory patterns
Mediterranean style eating (built around vegetables, olive oil, fish, and whole grains) and the DASH diet (Dietary Approaches to Stop Hypertension, an eating pattern designed to support healthy blood pressure) are reasonable defaults, given their track record for heart and metabolic health, both of which are frequently affected in PCOS.
Some research suggests approaches that start with a bigger calorie reduction early on can outperform a flat, moderate calorie reduction for certain markers (weight lost, SHBG, a protein that carries hormones like testosterone in the blood, and fasting blood sugar) over the short term[17]. Even so, any approach should be personalized, sustainable, and discussed with a qualified professional rather than attempted alone at the extremes.
What the evidence actually supports
PCOS is heavily marketed to, and a lot of supplement claims outpace the evidence. These three have the most consistent research behind them.
Myo inositol
Myo inositol is a naturally occurring compound (a type of sugar alcohol, not a sugar that raises blood glucose) involved in how the body responds to insulin. People with PCOS often show a very different balance of myo inositol to another related compound called D chiro inositol, compared with those who do not have PCOS[19]. Clinical guidelines are also more likely to mention inositol specifically than most other supplements[20]. Research links myo inositol with improved insulin sensitivity, more favourable androgen levels, and higher odds of regular cycles[21]. Current evidence favours myo inositol on its own over combined myo and D chiro inositol formulas[22].
The dose range used in most published research (roughly 1 to 4 grams total per day)[23]. Benefits can take anywhere from a few weeks to 3 to 6 months to become noticeable. Taking it twice a day rather than once may give steadier coverage[24].
A shortage of vitamin D is common in PCOS and is linked with higher androgen levels[25]. Correcting a deficiency has been linked with lower androgen levels and more regular cycles[26]. Testing your levels before supplementing is the sensible first step.
EPA and DHA are two types of omega 3 fats found in fish oil. This is the dose used in research improving hormone markers in PCOS[27]. Fish oil supplements are usually needed to reach this amount from diet alone.
These figures reflect commonly studied research amounts, shared for general education. They are not a personal recommendation. Always check with a doctor, dietitian, or pharmacist before starting a supplement, especially alongside other medication.
Other supplements, such as berberine, chromium, cinnamon, and NAC (short for N acetylcysteine, a supplement sometimes studied for insulin resistance), come up frequently in PCOS marketing, with more limited or mixed evidence. Before adding another supplement, it is worth weighing the financial and mental cost against the modest research support most of them currently have.
Movement helps, even without weight loss
No single training style has been shown to be clearly best for PCOS. What matters most is finding something you can stick with.
Associated with improved body composition and fasting blood sugar in PCOS[28], and some research shows visceral fat can drop without any overall weight loss[31].
Shown to reduce waist and hip measurements and improve markers of excess androgens in PCOS populations[29].
HIIT stands for high intensity interval training, meaning short bursts of intense effort mixed with recovery. It improved insulin resistance in at least one PCOS trial, again independent of weight change[30].
Reducing time spent sitting and choosing a type of exercise someone genuinely enjoys tends to matter more for long term results than chasing a theoretically perfect routine.
"Do not do intense exercise, it spikes cortisol and makes PCOS worse." Cortisol is a stress hormone. Chronic, unmanaged stress does carry real health costs, but a temporary rise in cortisol caused by exercise is a normal physiological response, not a reason to avoid a workout someone actually enjoys.
Common claims, examined
| Common claim | What the evidence points to |
|---|---|
| "PCOS means your metabolism is fundamentally broken." | The evidence for a dramatically lowered metabolic rate across the board is weak. The widely cited figure appears to come from an outlier study. |
| "You have to go keto or very low carb to manage PCOS." | Lower GI and GL patterns can help, but very low carbohydrate eating is not required. Sticking with a moderate, sustainable pattern tends to matter more. |
| "Intense workouts will spike cortisol and make things worse." | A short term rise in cortisol from exercise is normal and should not discourage movement someone enjoys. |
| "You need myo and D chiro inositol together for it to work." | Most research supports myo inositol on its own. D chiro inositol taken alone may even worsen androgen levels and cycle regularity. |
| "Lean women with PCOS should still aim to lose weight." | Research in leaner PCOS populations tends to favour maintaining weight while focusing on food quality and exercise, rather than intentional weight loss. |
"PCOS is a complex syndrome. Take a view of the whole person in front of you, rather than hyperfocusing on the physiology behind why they might be struggling."
A guiding principle for supporting people with PCOSA quick summary
Weight loss helps, but is not the whole story. Even 5 to 10 percent can meaningfully shift symptoms for those in larger bodies. Lean PCOS is a different picture.
Fibre, moderate carbohydrate, and higher protein patterns have the most consistent support. Sustainability wins over strictness.
Myo inositol is worth discussing with a healthcare provider, especially alongside signs of insulin resistance.
Movement helps independent of weight change. The best type is the one you will actually keep doing.
Vitamin D and omega 3 may help if your levels run low. It is worth testing rather than guessing.
PCOS affects mood and quality of life too. Emotional support is part of managing it, not separate from it.
References
The claims marked with a bracketed number throughout this page point to the research below. This is a curated summary rather than a full systematic review, listed here in short form for anyone who wants to look further into the original studies.
- 1.Deswal, R., et al. (2020). The prevalence of polycystic ovary syndrome: a brief systematic review.
- 2.The Rotterdam ESHRE and ASRM Sponsored PCOS Consensus Workshop Group (2004). Revised 2003 consensus on diagnostic criteria and long term health risks related to polycystic ovary syndrome. Fertility and Sterility, 81(1), 19 to 25.
- 3.Mohamed, F. Y., et al. (2025); Cowan, S., et al. (2023). Reviews of the reproductive, metabolic, psychological, and dermatological characteristics of PCOS.
- 4.Alebić, M. Š., et al. (2014). The phenotype of polycystic ovary syndrome: association with BMI and insulin resistance.
- 5.Kauffman, R. P., et al. (2002). Insulin resistance in women with polycystic ovary syndrome.
- 6.Georgopoulos, N. A., et al. (2009). Basal metabolic rate is decreased in women with polycystic ovary syndrome and biochemical hyperandrogenemia and is associated with insulin resistance. Fertility and Sterility, 92(1), 250 to 255.
- 7.Peele, L., and Nuckols, G. (2024). No, PCOS doesn't lower BMR (scientific review). MacroFactor.
- 8.Daghestani, M. H., et al. (2018); Polak, A. M., et al. (2020). Ghrelin levels in relation to insulin resistance and obesity in PCOS.
- 9.Hirschberg, A. L., et al. (2004). Reduced meal related peptide (CCK) response and appetite regulation in women with PCOS.
- 10.Jena, D., et al. (2018); Carmina, E., et al. (2007). Visceral adipose tissue in women with PCOS compared with weight matched controls.
- 11.Scragg, J., et al. (2024); Dou, L., et al. (2024). Effects of weight loss on insulin resistance markers in PCOS.
- 12.Shang, Y., et al. (2021); Alenezi, S. A., et al. (2024). Effects of weight loss on hyperandrogenism in PCOS.
- 13.Kuchenbecker, W. K. H., et al. (2011); Oberg, E., et al. (2019). Effects of weight loss on menstrual regularity and fertility in PCOS.
- 14.Yang, K., et al. (2024); Mehrabani, H. H., et al. (2012). Effects of weight loss on lipid profile and blood pressure in PCOS.
- 15.Dokras, A., et al. (2016). Effects of weight loss on quality of life, depression, and self worth in PCOS.
- 16.Fong, S. L., et al. (2021). Weight loss as first line treatment in overweight and obese women with PCOS.
- 17.Deshmukh, H., et al. (2023). Comparison of an aggressive versus moderate energy deficit approach in PCOS.
- 18.Whigham, L. D., et al. (2014). Metabolic evidence of diminished lipid oxidation and increased protein oxidation overnight in women with PCOS.
- 19.Unfer, V., et al. (2014). Myo inositol effects in women with PCOS: a meta analysis of randomized trials.
- 20.Teede, H. J., et al. (2023). International evidence based guideline for the assessment and management of PCOS.
- 21.Greff, D., et al. (2023). Inositol is an effective and safe treatment in PCOS: a systematic review and meta analysis.
- 22.Basciani, S., et al. (2025). Effects of D chiro inositol supplementation alone on hormonal and menstrual outcomes in PCOS.
- 23.Fitz, V., et al. (2024). Inositol for PCOS: a systematic review of dosage, duration, and efficacy.
- 24.Orrù, B., et al. (2017). Myo inositol and D chiro inositol in the treatment of PCOS: dosage and timing considerations.
- 25.Gokosmanoglu, F., et al. (2020). Vitamin D deficiency as a risk factor for PCOS.
- 26.Karadag, C., et al. (2018); Jafari-Sfidvajani, S., et al. (2018). Effects of vitamin D supplementation on androgens and menstrual regularity in PCOS.
- 27.Zhou, X., et al. (2023); Yuan, T., et al. (2022). Omega 3 fatty acid supplementation and hormonal or metabolic markers in PCOS.
- 28.Kite, C., et al. (2022). Exercise and physical activity interventions in PCOS: effects on body composition and fasting glucose.
- 29.Ribeiro, V. B., et al. (2020). Effects of continuous and interval aerobic training on hyperandrogenism in PCOS.
- 30.Almenning, I., et al. (2015). Effects of high intensity interval training on insulin resistance in PCOS.
- 31.Kogure, G. S., et al. (2016). Resistance exercise and visceral fat reduction in PCOS, independent of weight loss.
Medical disclaimer
This page is for general educational and informational purposes only. It summarizes published research and clinical discussion on PCOS and is not intended as, and should not be used as, a substitute for professional medical advice, diagnosis, or treatment.
- Nothing on this page should be interpreted as a personal treatment plan, diagnosis, or prescription.
- Always seek the advice of a physician, endocrinologist (a doctor who specializes in hormone conditions), registered dietitian, or other qualified healthcare provider with any questions about a medical condition, medication, or supplement.
- Never disregard professional medical advice or delay seeking it because of something you read on this page.
- Supplement doses referenced here reflect commonly studied research amounts, not individualized recommendations. Check with a healthcare provider before starting any supplement, especially if you take other medications or are pregnant or breastfeeding.
- If you are experiencing a medical emergency, call your local emergency number immediately.
- Research on PCOS continues to evolve. Some information here may be updated or replaced by newer evidence over time.