PCOS / PMOS

PCOS and weight

Why losing weight with PCOS is often harder, and what really helps

For many women with polycystic ovary syndrome (PCOS/PMOS), weight is the biggest daily concern and at the same time the most common source of guilt. Many have heard the same advice for years: “Lose weight and everything will get better.” This advice overlooks the fact that the difficulty with weight in PCOS has a hormonal and metabolic basis.

The 2023 international guideline therefore does not see weight as a personal failure, but as part of the syndrome. The goal is not rapid weight loss, but a healthy metabolism, prevention of further weight gain and a better quality of life.

How common is a higher weight in PCOS?

A review from 2012 shows that women with PCOS more often have overweight, obesity and especially fat around the belly than women without the syndrome. The frequency differs greatly between countries and population groups. At the same time, a large share of women with PCOS have a normal weight. The syndrome is therefore not a result of a higher weight, but a higher weight makes almost all of its symptoms worse.

An Australian long-term study of young women also shows that women with PCOS gain weight faster over the years than other women. This is why the guideline recommends paying attention to the prevention of weight gain from adolescence.

Why does weight increase?

Insulin resistance is at the center. The cells respond less well to insulin, and the pancreas produces more insulin to keep blood sugar in the normal range. A high insulin level promotes fat storage and, in some women, increases hunger. At the same time, insulin stimulates the ovaries to produce androgens.

Androgens favor fat storage around the belly. This belly fat is hormonally active and in turn increases insulin resistance. The result is a cycle in which insulin, androgens and weight reinforce each other. Studies also show changes in the hormones that control hunger and fullness. Poor sleep, stress, low mood and some medicines make weight control even harder.

Are slim women affected too?

Insulin resistance is not only a question of weight. In a study using the most accurate method of measurement, about 75% of slim women with PCOS had insulin resistance, and almost all women with PCOS and a higher weight. This is why metabolic checks also concern slim women. A normal weight does not automatically mean a healthy metabolism.

What does weight loss achieve?

In women with a higher weight, a loss of just 5-10% of body weight can change a lot. The cycle often becomes more regular, ovulation returns, androgens fall, and blood sugar, blood lipids and blood pressure improve. The chances of pregnancy and the course of the pregnancy also benefit.

The goal therefore does not have to be an “ideal weight”. A small, lasting change is worth more than a large weight loss that is regained after a few months. For women with a normal weight, the goal is to prevent weight gain and to improve the metabolism through exercise.

How does weight affect the liver?

In the syndrome, insulin resistance and belly fat also raise the risk of fatty liver. Today this condition is called metabolic liver disease (MASLD), and it affects about 40% of women with PCOS. It causes no symptoms for many years, but it raises the risk of disease of the heart and blood vessels. The frequency, the effects and the testing of fatty liver are described in detail in the article PCOS, diabetes and metabolic syndrome.

Weight is the most important point of treatment here. In the early stages the condition can reverse. According to the 2024 European guideline, losing 5% of body weight reduces the fat in the liver. Losing 7–10% reduces the inflammation, and losing more than 10% can also improve fibrosis. Weight loss and exercise are the most effective treatment.

What does weight mean when trying for a baby?

In women with a higher weight who want to become pregnant, weight loss before conception improves ovulation. It also lowers the risk of gestational diabetes and high blood pressure in pregnancy. However, weight loss should not delay a necessary fertility treatment for many months, especially after the age of 35. Time is also a factor. More in the article “PCOS and infertility”.

What kind of diet helps?

According to the guideline, there is no special “PCOS diet” that is better than others. What matters is a balanced diet that a woman can build into her daily life in the long term and that suits her culture, her preferences and her circumstances. For weight loss, a moderate energy deficit is needed, regardless of the make-up of the diet.

Very strict diets in PCOS often lead to the so-called yo-yo effect: the woman loses weight quickly, then gains it back, often even more than before, and the cycle starts again. These diets can also trigger disordered eating. The guideline recommends considering a possible eating disorder before any change in diet. More in the article PCOS and quality of life.

Social media is full of “PCOS diets”, “detox” programs and supplements that promise fast results. They have no scientific basis, often cost a lot of money and leave the woman feeling that she has failed. There is also no proof that avoiding whole food groups, such as gluten or dairy, helps in the syndrome when there is no intolerance.

How does exercise help?

In PCOS, exercise works even without weight loss. It improves insulin sensitivity, blood sugar, blood lipids, fitness and mood. The guideline adopts the recommendations of the World Health Organization: at least 150 to 300 minutes of moderate activity per week or 75 to 150 minutes of vigorous activity, plus strength training on two days a week. For weight loss and for preventing weight from coming back, more activity is usually needed.

Reducing long periods of sitting is just as important. Every bit of extra movement in daily life counts. The best form of exercise is the one a woman enjoys and keeps up.

What is weight stigma?

The 2023 guideline gives special attention to weight stigma. Many women with PCOS are blamed for their weight, including in doctors' practices. This experience leads women to avoid appointments, withdraw and stop treatment. The guideline therefore recommends raising weight only with the woman's consent, with respect, without blame, and with a focus on health rather than on the number on the scale.

Which medicines can help?

Metformin. Metformin improves insulin sensitivity and can contribute to a slight weight loss in women with a higher weight. Its effect on weight, however, is small. The guideline sees the greatest benefit in women with a higher metabolic risk. Common side effects concern the stomach and bowel. With long-term use, checking vitamin B12 makes sense.

Medication for weight loss. For the first time, the 2023 guideline mentions medication for weight loss, especially GLP-1 receptor agonists, as an option for adult women with a higher weight, together with lifestyle changes. First studies in PCOS show clear weight loss, a more regular cycle and lower androgens. The number of studies is growing quickly, but large long-term studies are still missing. Reliable contraception is needed during treatment. When a woman wishes to become pregnant, she stops these medicines early, before conception. After stopping, weight increases again in many women.

A 2026 meta-analysis in the European Journal of Endocrinology, with 11 randomized trials, found that GLP-1 receptor agonists lower the body mass index by about 2 points compared with placebo. They also seem to make the cycle more regular. The certainty of the evidence is low, however, because most trials were small and short. The most common side effects affect the stomach and bowel and are usually mild. According to the product information, a woman should stop semaglutide at least two months before a planned pregnancy. Tirzepatide can reduce the effect of the contraceptive pill, mainly in the first four weeks and after each increase in dose. During these phases, an additional method of contraception is needed.

Surgery. In severe obesity, weight loss surgery may be considered. It often also improves the cycle and the metabolism. After surgery, a woman should avoid pregnancy during the phase of rapid weight loss, and a later pregnancy needs special care.

The randomized BAMBINI trial (The Lancet, 2024) compared surgery with medication and lifestyle treatment in 80 women with the syndrome and severe obesity. After one year, the median number of spontaneous ovulations was 6 after surgery and 2 in the other group. Complications were more common after surgery, however, about 67% compared with 30%, with no lasting effects. The decision for surgery is therefore individual and needs cooperation with a specialized center.

Inositol and supplements. The guideline still considers inositol and other supplements experimental. A clear benefit for weight has not been shown. Their use belongs in a discussion with the doctor, with realistic expectations, and they do not replace a treatment with proven effect.

The practice's approach

Sources: International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (Monash University, ESHRE, ASRM, 2023); Teede HJ et al., Human Reproduction 2023. Lim SS et al., Overweight, obesity and central obesity in women with polycystic ovary syndrome, Human Reproduction Update 2012. Teede HJ et al., Longitudinal weight gain in women identified with polycystic ovary syndrome, Obesity 2013. Stepto NK et al., Women with polycystic ovary syndrome have intrinsic insulin resistance on euglycaemic–hyperinsulaemic clamp, Human Reproduction 2013. WHO – Guidelines on physical activity and sedentary behavior (2020). GLP-1 receptor agonist treatment in women with polycystic ovary syndrome – a systematic review and meta-analysis, European Journal of Endocrinology 2026. Samarasinghe SNS et al., Bariatric surgery for spontaneous ovulation in women living with polycystic ovary syndrome: the BAMBINI randomized controlled trial, The Lancet 2024. Chang RJ, Kazer RR, Polycystic Ovary Syndrome, The Global Library of Women's Medicine (GLOWM). EMA – Wegovy (semaglutide) and Mounjaro (tirzepatide), product information. EASL–EASD–EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD), Journal of Hepatology 2024.