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ingestible · for fertility & reproductive health

Myo-Inositol (with D-Chiro-Inositol)

Reviewed by the Nimbera editorial team · Last updated May 2026

Unfer 2017 Endocrine Connections (PMID 29042448) - meta-analysis of 9 RCTs (n=496 women with PCOS); myo-inositol supplementation significantly reduced fasting insulin (SMD -1.02 µU/mL, 95% CI -1.79 to -0.25, p=0.009) and HOMA-IR index (p=0.041), and raised SHBG in trials lasting 24+ weeks, indicating reduced hyperandrogenism and improved ovulatory function.$20-$40/month for a 4 g daily dose

How to use

The most studied dose is 4 g myo-inositol plus 400 mg folic acid daily, often taken as a powder mixed in water. A 40:1 ratio of myo-inositol to D-chiro-inositol (e.g. 4000 mg:100 mg) mirrors the physiological ratio in follicular fluid. Take in two divided doses, morning and evening, for at least 12 weeks to assess effect.

How it works

Inositol is a secondary messenger in insulin signaling. Women with PCOS have impaired inositol metabolism, leading to insulin resistance and elevated androgens that disrupt follicle development and ovulation. Myo-inositol restores insulin sensitivity at the ovarian level, lowering LH:FSH ratios and testosterone, which improves follicle selection and menstrual regularity.

Where to buy

Theralogix Ovasitol and Fairhaven Health Pregnitude are PCOS-specific formulas widely available online. Standalone myo-inositol powder is also available from NOW Foods and Bulk Supplements. Available at Amazon and fertility-focused supplement retailers.

Typical cost: $20-$40/month for a 4 g daily dose

Safety notes

Generally very safe with minimal side effects; occasional mild GI upset at high doses. The 2023 International Evidence-based PCOS Guidelines note evidence is still limited for some outcomes - do not substitute for metformin or other prescribed treatments without medical guidance. Safety in early pregnancy is not well established; discuss continuation with your doctor after a positive test.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Unfer 2017 - Endocrine Connections (PMID 29042448)

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.