The PCOS market mainly sells inositol capsules with the “perfect 40:1 ratio” and gluten-free diets. International guidelines, meanwhile, prioritise physical activity, sleep and metabolic monitoring, and none endorses an ideal ratio.
PCOS has not just changed its name. It has finally shed two misleading ideas: the follicles observed are not cysts, and the ovaries are not the only organs involved.
Since May 2026, the international consensus has used the term polyendocrine metabolic ovarian syndrome, or PMOS. In French, Inserm uses syndrome métabolique ovarien polyendocrinien, or SMOP. The new name brings insulin, androgens, ovulation, sleep and cardiovascular risk into view.
That does not make insulin the sole cause. Some slim women with no measurable insulin resistance have significant hyperandrogenism and ovulatory dysfunction. A useful protocol therefore starts by confirming the diagnosis and phenotype, then targets the problems actually present. Neither the pill, metformin nor inositol is a universal answer.
From PCOS to PMOS: why the name is changing and what it means
The consensus published in The Lancet follows consultations with 14,360 patients and professionals, involving 56 clinical, scientific and patient organisations. The chosen term describes three dimensions:
- polyendocrine, because several hormonal signals are involved
- metabolic, because the risk of dysglycaemia, diabetes, dyslipidaemia and sleep apnoea extends beyond weight
- ovarian, because ovulatory dysfunction and infertility remain central
The transition from PCOS to PMOS is expected to take several years. Publications, software and doctors will continue to use both terms. Above all, the name change does not alter diagnostic criteria or current treatments.
In adults, diagnosis requires two of the following three criteria, after excluding other causes:
- irregular cycles or absent ovulation
- clinical or biochemical hyperandrogenism
- consistent ovarian morphology on ultrasound, or AMH used as an alternative in adults
If irregular cycles and hyperandrogenism are already present, ultrasound and AMH are not needed to add a third piece of evidence. An ultrasound alone does not establish a diagnosis. Thyroid disorders, prolactin abnormalities, congenital adrenal hyperplasia, pregnancy and rarer causes must be ruled out according to the clinical picture.
A cycle longer than 90 days, very high testosterone, rapid virilisation, unusual bleeding or plans for pregnancy warrant a consultation without waiting for the protocol.
The real metabolic driver: hyperinsulinaemia, but not in everyone
When muscles, the liver and adipose tissue respond less effectively to insulin, the pancreas secretes more of it. This hyperinsulinaemia can stimulate ovarian androgen production and reduce hepatic SHBG production. More testosterone then remains free, which can worsen acne, excess hair growth and follicular maturation.
This cycle can exist even before fasting blood glucose rises. But it varies with phenotype, genes, age, sleep, central adiposity and treatments. Insulin resistance is not a mandatory criterion for PMOS.
HOMA-IR does not have the final say
HOMA-IR combines fasting blood glucose and insulin. It seems ideal for measuring hyperinsulinaemia, but insulin assays are poorly standardised, and thresholds vary between populations and laboratories. The international guideline therefore advises against its routine use to diagnose or guide PCOS management.
The HOMA-IR calculation guide · FR helps explain the formula, not establish a diagnosis. For glycaemic status, the oral test using 75 g of glucose is considered the most accurate, regardless of BMI. Fasting blood glucose and HbA1c are less sensitive alternatives if this test is not feasible.
The initial assessment also considers blood pressure, lipid profile and cardiovascular risk. Glycaemic assessment is repeated every one to three years depending on risk factors, and before pregnancy or fertility treatment.
Inositol: myo, D-chiro, ratios and actual doses
Myo-inositol and D-chiro-inositol participate in insulin-related signalling pathways. This plausibility is not enough to establish which product is best.
The analysis underpinning the 2023 guideline included 30 trials and 2,230 participants. It found possible improvements in some metabolic markers, but no effects on other outcomes, with evidence that was limited and inconclusive overall. A 2026 umbrella review found reductions in testosterone, insulin and HOMA-IR, as well as promising findings on ovulation. Of 85 pieces of evidence, none reached high quality, and 81% were of low or very low quality.
Another 2026 meta-analysis adds a useful nuance. Among 440 women, improvements in testosterone were mainly observed in the normal-weight subgroup, not in women identified as insulin-resistant regardless of weight. The authors describe this finding as exploratory. It at least challenges the simplistic idea that inositol only works in “metabolic” PCOS with excess weight.
The 3.6:1 ratio is not established as optimal
Published protocols include several regimens:
| Formulation studied | Example daily amount | How to interpret it |
|---|---|---|
| Myo-inositol alone | often 2 g twice daily | common regimen, not a universal dose |
| 40:1 ratio | 2 g of myo + 50 mg of D-chiro, twice daily | common in trials; superiority of the ratio not established |
| 3.6:1 ratio | 550 mg + 150 mg twice daily in an open-label trial | small trial, no placebo and findings not generalisable |
| 3.6:1 product with antioxidants | amount depends on the product studied | retrospective IVF data; impossible to isolate the ratio’s effect |
The new 2026 multimodal trial used the 40:1 ratio with metformin and calorie restriction. After twelve weeks, the combination improved BMI, HOMA-IR and menstrual regularity more than each intervention alone. But the trial was short, open-label and registered after the primary follow-up had ended. It cannot tell us how much of the effect came from the energy deficit, metformin or inositol.
The clinical rule remains the one in the international guideline: no type, dose or ratio of inositol can be confidently recommended. If you decide on a trial with your doctor or pharmacist, check the amount of each isomer, the other ingredients, digestive tolerability and the outcome being measured.
Can inositol and metformin be combined?
They have been combined in trials without a clearly established signal of a dangerous interaction. That does not make the duo necessary. Tell your prescriber, especially if you take other glucose-lowering treatments, and do not adjust metformin based on a HOMA score calculated at home.
Metformin has stronger guideline support for metabolic goals, particularly from a BMI of 25 kg/m² upwards. It may also be considered below this threshold, with more limited evidence. Its digestive side effects and the risk of low vitamin B12 over the long term should be discussed.
During pregnancy, a randomised trial of 464 women with PCOS found no reduction in gestational diabetes, pre-eclampsia or preterm birth with 2 g of myo-inositol twice daily. Do not automatically carry a preconception protocol over into pregnancy.
Berberine, chromium and NAC: what helps and what is overhyped
These supplements mainly produce changes in biomarkers in short trials:
| Option | Available signal | Limitation that changes the decision |
|---|---|---|
| Berberine | possible improvements in glucose, lipids or weight | variable study quality, drug interactions; avoid during pregnancy and breastfeeding |
| NAC | promising findings on progesterone and endometrial thickness | intermediate outcomes, no robust evidence on live birth, conflicts of interest in a 2025 meta-analysis |
| Chromium | possible small improvements in insulin and some lipids | short, heterogeneous trials; no central role in guidelines |
The 2026 study on the combination of berberine and inositol was conducted in cells and a mouse model. It does not validate a human “stack”. Berberine interacts with certain medicines and may expose infants to a bilirubin-related risk. Our analysis of berberine and its metabolic limitations · FR explains why it is not natural Ozempic.
Do not stack four supplements before your assessment. You will not know what works or what causes diarrhoea, nausea or cycle disruption.
Exercise and body composition: a shared lever across phenotypes
Exercise improves cardiorespiratory fitness and some insulin markers even without weight loss. In 2026, a network meta-analysis of 23 trials and 1,192 participants found a small advantage for moderate continuous activity on HOMA-IR, while high-intensity interval training improved VO2max and fasting insulin more. Certainty remained low to moderate, and no format significantly improved every marker.
The recommended framework is simpler:
- 150 to 300 minutes of moderate aerobic activity per week, or 75 to 150 minutes of vigorous activity
- resistance training on at least two non-consecutive days
- less time sitting, particularly through short walks after meals
- progression based on symptoms, fitness and preferences
At a normal weight, the goal is not to create a deficit. Instead, measure strength, endurance, waist circumference if relevant, blood pressure and cycle regularity. At a higher weight, if weight loss is desired, the energy deficit should remain individualised. The guideline finds no diet superior to the others.
Irregular cycles make exercise programming around theoretical phases unreliable. Adjust training load and recovery to the symptoms you observe rather than “day 14”. For fertility, temperature and ovulation-tracking tools mainly confirm ovulation after it has occurred and do not replace an assessment.
Sleep, cortisol, gluten and dairy
Obstructive sleep apnoea is more common in PMOS regardless of BMI. Snoring combined with unrefreshing sleep, daytime sleepiness or fatigue warrants formal screening. Optimising a watch or a commercial “salivary cortisol” test does not treat apnoea.
For 90 days, aim for a regular schedule and enough sleep to function without sleepiness. Insufficient sleep can adversely affect hunger, activity and insulin sensitivity. No breathing protocol has been shown to normalise androgens on its own.
No evidence justifies routinely cutting out gluten or dairy. Suspected coeliac disease should be tested for before gluten is removed. Exclusion is justified by an allergy, intolerance or reproducible symptoms, not by a PMOS diagnosis. This caution matters because eating disorders are more common regardless of weight.
A 90-day protocol in three phases
This protocol complements gynaecological or endocrinological care. It does not replace contraception, endometrial protection, metformin or fertility treatment when indicated.
Phase 1: confirm the diagnosis and define the target
Before day 1, gather the following:
- cycle dates over six to twelve months and a pregnancy test if relevant
- signs of hyperandrogenism and prescribed hormone tests
- blood pressure, lipids and glycaemic status, ideally a 75 g OGTT
- medicines, supplements, pregnancy plans and contraception
- symptoms of apnoea, anxiety, depression or disordered eating
Choose one main goal measurable at 90 days: improve exercise tolerance, reduce waist circumference if needed, establish consistent meals or document cycles. Excess hair growth and fertility often need more time.
Phase 2: days 1 to 30, build the foundation
Build each week around four actions:
- two progressive resistance-training sessions
- aerobic activity and walking, building towards the recommended volume
- regular meals with protein, fibre-rich plant foods, minimally refined carbohydrates and suitable fats
- a consistent wake-up time, with screening if apnoea symptoms are present
Start no more than one optional supplement after checking its compatibility. Record the product, form, amount, digestion and adherence. Stop and seek advice if you have an allergic reaction, significant digestive symptoms, feel unwell or become pregnant.
Phase 3: days 31 to 90, progress and reassess
Gradually increase volume or weights without persisting with restriction that further disrupts your cycles. Keep prescribed treatments stable unless a medical decision is made to change them.
On day 90, compare the following indicators:
- interval between periods and possible signs of ovulation
- waist circumference or weight only if that goal was relevant
- strength, weekly activity and sleep quality
- blood pressure and laboratory markers selected with your doctor
- adverse effects and the actual cost of supplements
Do not wait three months without advice if your periods are absent. Prolonged amenorrhoea increases the risk of endometrial hyperplasia. Cycle regulation with contraception or a progestogen, depending on the situation, may be needed even while the metabolic strategy continues.
Fertility and treatments: when natural approaches are not enough
Irregular ovulation does not rule out pregnancy. Contraception is still needed if pregnancy is not wanted. If it is, OGTT, blood pressure, medicines and preconception folate should be discussed before trying.
For anovulatory infertility with no other contributing factor, letrozole is the first-line pharmacological treatment in the international guideline. Its use remains off-label for this indication in some countries and requires supervision. Inositol is still considered experimental for fertility in this guideline, despite favourable findings in meta-analyses.
The 2026 network meta-analysis ranks GLP-1 agonists, alone or with metformin, ahead of inositol and metformin for weight loss, at around 5 kg on average. It measured neither ovulation, live birth nor quality of life, and found no significant improvement in HOMA-IR. These medicines are not natural treatments for PMOS and require contraception, a medical indication and consideration of weight regain after stopping.
The new name PMOS therefore broadens management without reducing it to insulin. The strongest protocol treats the phenotype present, protects the endometrium, separates metabolism from fertility, then measures results before adding a supplement.
