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Myo-Inositol for PCOS: What the Meta-Analyses Show

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

A 2017 meta-analysis of randomized trials found myo-inositol was associated with significant improvements in fasting...

A 2017 meta-analysis of randomized trials found myo-inositol was associated with significant improvements in fasting insulin and insulin resistance (HOMA index) in women with PCOS, with a trend toward lower testosterone. Evidence is encouraging but mixed — some later analyses found smaller or non-significant effects — so myo-inositol is best considered with a clinician as part of a broader PCOS plan.

Key Findings

  • A 2017 meta-analysis (9 RCTs; 247 treated, 249 controls) found myo-inositol was associated with significant reductions in fasting insulin and HOMA insulin-resistance index in women with PCOS.
  • Sex-hormone-binding globulin (SHBG) increased significantly when treatment lasted at least 24 weeks, with a trend toward reduced testosterone.
  • Because insulin resistance and elevated androgens drive many PCOS symptoms, these metabolic changes are mechanistically relevant.
  • Evidence is mixed: a later meta-analysis found no significant change in several metabolic and endocrine outcomes, so effects are not guaranteed.

Study Details

Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials
Unfer V, Facchinetti F, Orrù B, Giordani B, Nestler J — Endocrine Connections (2017)
Myo-inositol was associated with significant reductions in fasting insulin and HOMA index in women with PCOS; SHBG rose with ≥24 weeks of treatment.
496 participantsModerate

Practical Takeaway

Myo-inositol has been studied for supporting metabolic and hormonal measures in women with PCOS, with meta-analyses showing improvements in insulin sensitivity and, with longer use, SHBG. The evidence is encouraging but inconsistent, and PCOS is a medical condition that needs proper diagnosis and management. Myo-inositol is best considered as one part of a clinician-guided plan — not a self-directed treatment — and anyone pregnant, trying to conceive, or on other medications should consult their healthcare provider first.

Summary

Meta-analyses report that myo-inositol was associated with improved insulin measures in women with PCOS, though the broader evidence is mixed.

Related Supplements

Myo-Inositol

Related Conditions

Polycystic Ovary Syndrome (PCOS)Blood Sugar ManagementFertility

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Frequently Asked Questions

Does myo-inositol help with PCOS?

A meta-analysis found myo-inositol was associated with improved insulin sensitivity (lower fasting insulin and HOMA index) in women with PCOS, and higher SHBG with longer use. The evidence is encouraging but mixed, so results vary and it is best used as part of a clinician-guided plan.

How much myo-inositol is studied for PCOS?

Trials commonly used myo-inositol around 2–4 g/day, sometimes combined with d-chiro-inositol. Because PCOS care should be individualized, confirm an appropriate regimen with your clinician.

Can myo-inositol help with fertility or ovulation in PCOS?

Some studies suggest myo-inositol may support ovulatory function by improving insulin sensitivity, but evidence is mixed and fertility care is highly individual. If you are trying to conceive, discuss options with your clinician rather than self-treating.

Is myo-inositol safe?

Myo-inositol was generally well tolerated in studies, with mild digestive effects at higher doses. Still, PCOS is a medical condition, and anyone pregnant, breastfeeding, or on medication should check with a clinician before starting.

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Supplement Guide

Myo-Inositol

Bottom line: Myo-inositol is a first-line supplement for PCOS, improving insulin resistance and restoring ovulation. Take 4g daily with 400mcg folic acid.

Product Comparison

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Condition Guide

Polycystic Ovary Syndrome (PCOS)

References

  1. Unfer V, Facchinetti F, Orrù B, Giordani B, Nestler J (2017). Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials. Endocrine Connections. DOI PubMed
  2. Jethaliya H, Gajjar N, Patel V, Deshpande S, Patel R (2022). Efficacy of Myo-inositol on Anthropometric, Metabolic, and Endocrine Outcomes in PCOS Patients: a Meta-analysis of Randomized Controlled Trials. Reproductive Sciences. DOI PubMed