Two of the most commonly recommended treatments for polycystic ovary syndrome — myo-inositol and metformin — are facing serious scrutiny after recent clinical trials found they may not work as well as doctors hoped, and in some cases, could pose risks to children exposed during pregnancy. A major JAMA-published randomized controlled trial in September 2025 found that myo-inositol supplementation did not reduce gestational diabetes, preeclampsia, or preterm birth in pregnant women with PCOS, while a separate analysis published in BJOG found that children exposed to metformin in utero had nearly a fivefold increase in allergy incidence by age eight. For the millions of women managing PCOS — and for the families who support them, including those navigating other chronic health conditions like dementia — this research raises uncomfortable questions about treatments that have become almost reflexive in clinical practice.
Myo-inositol in particular has exploded in popularity as an over-the-counter supplement, often marketed with promises that now appear to outpace the evidence. Metformin, a diabetes drug long repurposed for PCOS, remains useful in many contexts but carries newly documented concerns when taken during pregnancy. This article breaks down what the new research actually found, where the evidence stands for both myo-inositol and metformin, what the international guidelines now say, and what women with PCOS should consider when discussing treatment options with their doctors.
Table of Contents
- What New Research Is Questioning About PCOS Drugs — and Why It Matters Now
- The Inositol Evidence Gap — What Guidelines Actually Say
- Metformin’s Pregnancy Dilemma — Maternal Benefit Versus Child Risk
- What Women with PCOS Should Discuss with Their Doctors Now
- Why PCOS Treatment Remains So Challenging
- The Supplement Industry Problem
- Where PCOS Research Goes from Here
- Conclusion
- Frequently Asked Questions
What New Research Is Questioning About PCOS Drugs — and Why It Matters Now
The headline finding comes from the MYPP trial, a multicenter, double-blind, randomized controlled trial conducted across 13 hospitals in the Netherlands. Researchers enrolled 464 pregnant women with PCOS and gave half of them 4 grams per day of myo-inositol while the other half received a placebo. The primary outcome — a composite of gestational diabetes, preeclampsia, and preterm birth — occurred in 25.0 percent of the myo-inositol group versus 26.8 percent of the placebo group. The relative risk was 0.93, with a 95 percent confidence interval of 0.68 to 1.28 and a P value of 0.67. In plain language, the supplement made no statistically meaningful difference. this matters because myo-inositol has become one of the most popular supplements among women with PCOS, driven by social media recommendations, wellness influencers, and preliminary smaller studies that suggested benefits.
Walk into any health food store or browse any PCOS forum online, and you will find myo-inositol treated almost as a given. The MYPP trial is exactly the kind of rigorous, large-scale study that separates preliminary hope from proven benefit — and for pregnancy complications, the benefit was not there. Meanwhile, metformin is facing its own reckoning. A post hoc analysis of two randomized controlled trials and a follow-up study, published in BJOG: An International Journal of Obstetrics and Gynaecology, tracked 634 women with PCOS who took either metformin or placebo throughout pregnancy and then followed 145 of their children to age eight. The children who had been exposed to metformin in utero had an allergy incidence nearly fivefold higher, with an odds ratio of 4.83, and an eczema risk that more than doubled, with an odds ratio of 2.42. These are not trivial numbers, and they complicate a drug that many clinicians have considered safe during pregnancy.
The Inositol Evidence Gap — What Guidelines Actually Say
The JAMA trial did not arrive in a vacuum. The 2023 International Evidence-Based PCOS Guidelines, which involved a systematic review and meta-analysis, had already concluded that the evidence supporting inositol for PCOS was “limited and inconclusive.” The guideline authors stated that specific types, doses, or combinations of inositol cannot currently be recommended due to a lack of high-quality evidence. This is the guideline that most endocrinologists and reproductive medicine specialists around the world reference when making treatment decisions. A 2026 umbrella review published in Frontiers in Endocrinology went further, applying AMSTAR-2 quality ratings to existing inositol meta-analyses. The results were sobering: only 23.1 percent of the meta-analyses were rated as high quality, while 53.8 percent were rated low and 23.1 percent very low.
When the authors applied the GRADE framework to assess the certainty of the evidence, they found no high-quality evidence at all — 18.9 percent was moderate, 40 percent was low, and 41.1 percent was very low. This means the studies that have been used to justify inositol supplementation for PCOS are, by the most respected quality metrics in medicine, largely unreliable. However, it is important to note what this does not mean. The research does not prove that myo-inositol is harmful, nor does it rule out the possibility that inositol could have benefits in specific PCOS subpopulations or at different doses. What it does say is that the current enthusiasm has far outstripped the evidence, and women should not assume this supplement is doing what they hope it is doing — particularly during pregnancy. A 2025 article in Reproductive BioMedicine Online captured this tension perfectly in its title: “Myo-inositol in reproductive management of women with PCOS: holy grail for medical practice or demon for scientific evidence?”.
Metformin’s Pregnancy Dilemma — Maternal Benefit Versus Child Risk
The metformin findings create a particularly difficult clinical puzzle because the drug does appear to offer some benefits to the mother. The same research that flagged allergy and eczema risks in offspring also found that metformin reduced maternal infections during pregnancy, particularly viral infections. For a pregnant woman with PCOS who is already at elevated risk for complications, that is a meaningful benefit. But it comes at a cost that does not show up until years later, in the health of the child. Consider a specific scenario: a woman with PCOS becomes pregnant and her doctor suggests metformin to help manage insulin resistance and reduce infection risk during the pregnancy.
Based on the BJOG data, her child would face roughly a one-in-five chance of developing allergies by age eight if exposed to metformin in utero — nearly five times the rate seen in the placebo group. Eczema risk more than doubles. These are conditions that, while manageable, affect quality of life and can persist for years. Researchers presenting at the ESPE/ESE 2025 Congress went so far as to say that “metformin therapy cannot be recommended for pregnant women with PCOS due to lack of effect and offspring safety concerns.” That is a strong statement from a major endocrinology conference, and it signals a shift in how the medical community is thinking about this drug’s role during pregnancy. It is worth noting that metformin remains well-supported for managing insulin resistance and metabolic symptoms in non-pregnant women with PCOS — the concern is specifically about in-utero exposure.
What Women with PCOS Should Discuss with Their Doctors Now
The practical takeaway from this research is not that women should stop all PCOS treatment, but that conversations with doctors need to become more specific and more honest about what the evidence supports. For women who are pregnant or planning to become pregnant, the question of whether to use myo-inositol or metformin now carries different weight than it did two years ago. For myo-inositol, the Italian Society of Endocrinology Delphi consensus and international guidelines now state that myo-inositol should not be used for improving fertility in infertile individuals with PCOS. It is not endorsed as a first-line treatment for PCOS-related infertility.
Women spending significant money on inositol supplements with the expectation that they will improve their chances of conception or reduce pregnancy complications should know that the best available evidence does not support that expectation. For metformin, the tradeoff is different. Outside of pregnancy, metformin continues to have a solid evidence base for managing insulin resistance in PCOS. During pregnancy, however, the new allergy and eczema data introduce a risk that needs to be weighed against the maternal infection benefit. This is the kind of decision that cannot be made from a blog post or a supplement label — it requires an individualized conversation with a physician who understands the patient’s full medical picture, risk factors, and priorities.
Why PCOS Treatment Remains So Challenging
A 2026 review published in Biomedicines offered a broader critique that helps explain why these treatment failures keep happening. The authors noted that current PCOS management, which relies heavily on oral contraceptives and metformin, offers only “symptomatic relief or masking of the phenotype” without disrupting the core pathophysiological loop. In other words, the most common treatments manage symptoms without addressing the underlying hormonal and metabolic dysfunction that drives PCOS. This is a familiar pattern in medicine, and it echoes challenges seen in other chronic conditions, including neurodegenerative diseases like Alzheimer’s.
When you treat symptoms without addressing root causes, you can achieve short-term improvement while missing the bigger picture. The Biomedicines review also flagged “potential intergenerational safety concerns” — a reference to the metformin offspring data and a warning that treatments used during reproductive years may have consequences that extend beyond the patient herself. The limitation here is that no clearly superior alternative has emerged. Researchers are exploring precision-targeted therapies for PCOS, but these are still in early stages. For now, women and their doctors are working with imperfect tools, which makes it all the more important to use those tools based on the best available evidence rather than on marketing claims or outdated assumptions.
The Supplement Industry Problem
Myo-inositol’s trajectory illustrates a broader issue with the supplement industry: products can achieve massive market penetration based on preliminary research, consumer testimonials, and social media momentum long before rigorous trials confirm or deny their effectiveness. Unlike prescription drugs, supplements do not require FDA approval for efficacy before they are sold.
By the time the MYPP trial delivered its null result, myo-inositol was already a staple in the PCOS community, recommended by influencers and stocked in every pharmacy. This does not make the supplement dangerous, but it does mean that many women have been spending money and building treatment plans around a product whose pregnancy-related benefits have now failed to hold up under rigorous testing. The gap between how inositol is marketed and what the science supports is wide, and closing it will require not just better research but better communication between researchers, clinicians, and patients.
Where PCOS Research Goes from Here
The next phase of PCOS research is likely to move in two directions. First, expect more granular studies that look at whether specific subgroups of women with PCOS — defined by phenotype, insulin resistance severity, or genetic markers — might respond differently to treatments like inositol or metformin. The current evidence suggests that treating all PCOS as a single condition leads to disappointing results because the syndrome is heterogeneous.
Second, the offspring safety data from the metformin studies will likely trigger longer-term follow-up research. Tracking children exposed to metformin in utero beyond age eight will be critical for understanding whether the allergy and eczema signals grow, stabilize, or resolve over time. For families already navigating complex health conditions — including those caring for loved ones with dementia or other chronic diseases — these long-term safety questions resonate deeply. The principle is the same across medicine: treatments should be evaluated not just by their immediate effects but by their downstream consequences, sometimes across generations.
Conclusion
The research challenging myo-inositol and metformin for PCOS does not mean these treatments are useless in all contexts. Metformin remains a legitimate tool for managing insulin resistance outside of pregnancy, and inositol may yet show benefits in specific populations or for specific outcomes. But the evidence is now clear that myo-inositol does not reduce pregnancy complications in women with PCOS, that it is not recommended for fertility by international guidelines, and that metformin during pregnancy carries meaningful risks to offspring that were not previously well documented.
For women with PCOS, the most important next step is an honest conversation with a knowledgeable physician — one that moves beyond the defaults of “take this supplement” or “here’s a metformin prescription” and instead weighs the specific evidence for each patient’s situation. Medical knowledge evolves, and treatments that seemed promising a few years ago sometimes turn out to be less effective or less safe than hoped. Staying current with the research, asking hard questions, and resisting the pull of oversimplified solutions will serve patients better than any single pill or supplement.
Frequently Asked Questions
Is myo-inositol safe to take for PCOS?
Myo-inositol has not been shown to be dangerous, but the most rigorous clinical trial to date — the MYPP trial published in JAMA in September 2025 — found it did not reduce gestational diabetes, preeclampsia, or preterm birth in pregnant women with PCOS. International guidelines describe the evidence as “limited and inconclusive” and do not recommend it for fertility treatment.
Should I stop taking metformin if I have PCOS and am pregnant?
Do not stop any medication without consulting your doctor. The new research showing increased allergy and eczema risk in children exposed to metformin in utero is significant, but metformin also reduced maternal infections during pregnancy. This is a decision that must be made individually with your physician based on your specific risk profile.
Does metformin still work for PCOS outside of pregnancy?
Yes. The new safety concerns are specifically about metformin use during pregnancy and its effects on offspring. For managing insulin resistance and metabolic symptoms in non-pregnant women with PCOS, metformin continues to have a supported evidence base, though researchers note it addresses symptoms rather than root causes.
Why do so many people recommend inositol for PCOS if the evidence is weak?
Inositol gained popularity through early smaller studies, social media advocacy, and the supplement industry’s marketing. Because supplements do not require the same FDA approval process as prescription drugs, products can become widely used before large-scale trials confirm or deny their benefits. A 2026 umbrella review found that only 23.1 percent of inositol meta-analyses met high-quality standards.
What alternatives exist for PCOS treatment?
Current standard treatments include oral contraceptives for menstrual regulation and metformin for insulin resistance, though a 2026 Biomedicines review noted these provide “symptomatic relief or masking of the phenotype.” Lifestyle modifications including diet and exercise remain foundational. Precision-targeted therapies are under investigation but are not yet widely available.
How does this affect families already managing other chronic conditions like dementia?
For families juggling multiple health conditions, the key lesson is the same: question treatments based on popularity rather than evidence, have specific conversations with physicians about risks and benefits, and monitor emerging research. Caregivers managing conditions like dementia understand that chronic disease management requires ongoing reassessment as new evidence emerges.
