Inositol (Myo-Inositol)
- Effective dose
- 2–4 g
- Evidence
- 3/5· Moderate
Last updated June 1, 2026
What it is
Myo-inositol is a sugar-alcohol that the body also makes itself; it acts as a second messenger in insulin and hormone signaling pathways. It is most studied in polycystic ovary syndrome (PCOS), where it is thought to improve insulin sensitivity.
Benefits
In PCOS, myo-inositol at about 4 g/day (typically 2 g twice daily, often with folic acid) has improved markers such as fasting insulin, HOMA-IR, and androgen levels and may support ovulation, though a 2023 guideline meta-analysis judged the overall evidence limited and inconclusive. Effects generally take 2-3 months to appear.
When to take it
Commonly split as 2 g twice daily with water; consistent daily use for at least 2-3 months is needed before assessing metabolic or menstrual effects.
Side effects
Well tolerated; at higher doses some people get mild gastrointestinal effects such as nausea, gas, or loose stools. Gastrointestinal side effects appear less frequent than with metformin.
Sources
Products containing Inositol (Myo-Inositol)
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