Myo-inositol
A sugar-like compound that acts as a second messenger in insulin and FSH signaling. It is proposed to improve insulin sensitivity and ovarian function, and is commonly combined with D-chiro-inositol (often in a 40:1 ratio).
Also known as inositol, D-chiro-inositol, myo-inositol / D-chiro-inositol, vitamin B8.
At a glance
Updated monthly · checked 10 h agoMyo-inositol is an insulin sensitizer marketed as a fertility supplement. It is not a fertility drug. Its computed evidence score is ~65/100. Among the better-evidenced options for PCOS-related ovulation problems, but the evidence quality is modest and it is not a general fertility booster.
- Randomized trials
- 67
- Systematic reviews
- 102Computed
- Real product labels indexed
- 20 in the NIH DSLD
Marketed to "restore ovulation" and improve egg quality, especially in PCOS.
Among the better-evidenced options for PCOS-related ovulation problems, but the evidence quality is modest and it is not a general fertility booster.
What the evidence says
Computed from the volume and type of primary studies, not the strength of the marketing. Each figure below links to its live search.
The best evidence is in PCOS, where several small trials and meta-analyses suggest improved ovulation and metabolic markers. The trials are small and varied, the effect on live birth is uncertain, and the benefit in people without PCOS is weak.
- Natural compounds in the management of polycystic ovary syndrome: a comprehensive review of hormonal regulation and therapeutic potential2025 · 37 citations
- Update on the combination of myo-inositol/d-chiro-inositol for the treatment of polycystic ovary syndrome2024 · 17 citations
- Inositol Restores Appropriate Steroidogenesis in PCOS Ovaries Both In Vitro and In Vivo Experimental Mouse Models2024 · 16 citations
- The Effects of Myo-Inositol and D-Chiro-Inositol in a Ratio 40:1 on Hormonal and Metabolic Profile in Women with Polycystic Ovary Syndrome Classified as Phenotype A by the Rotterda2024 · 16 citations
- The Role of Nutrient Supplements in Female Infertility: An Umbrella Review and Hierarchical Evidence Synthesis2024 · 15 citations
Source: europepmc+pubmed+openalex · as of Sep 25, 2026
Real product labels
Actual marketed supplement products indexed by the NIH Dietary Supplement Label Database. A product being on a shelf is not evidence it works.
- Myo-InositolFresh NutritionCapsule
- Myo-InositolOff marketFairhaven HealthCapsule
- Myo-InositolOff marketGenestra BrandsPowder
- Myo-Inositol PowderOff marketProtocol For Life BalancePowder
- Myo-Inositol Powder 2000 mgOff marketZazzee NaturalsPowder
- Myo-InositolOff marketGenestra BrandsPowder
- Myo-InositolGenestra BrandsPowder
- Myo-Inositol 2000 mgZazzee NaturalsCapsule
- Myo-Inositol for Women and MenFairhaven HealthCapsule
- Myo-Inositol PowderOff marketProtocol For Life BalancePowder
- Myo-Inositol PowderOff marketProtocol For Life BalancePowder
- Myo-Inositol PowderProtocol For Life BalancePowder
- Iron-Free MultipleSolgarTablet or Pill
- Inositol (Myo-Inositol) 2000 mgWholesome StoryCapsule
- Myo-Inositol PowderProtocol For Life BalancePowder
- SeroPlusOff marketPure EncapsulationsCapsule
- Myo-InositolPureCapsule
- Myo-Inositol Powder 2000 mgZazzee NaturalsPowder
- Myo-Inositol PowderProtocol For Life BalancePowder
- Myo-Inositol PowderOff marketProtocol For Life BalancePowder
Source: NIH Dietary Supplement Label Database (DSLD) · as of Sep 30, 2026
What to watch for
Generally well tolerated; high doses can cause mild GI upset such as nausea or gas.
What it actually is
Myo-inositol is a single, characterized compound. Its structure, molecular formula, weight, and synonyms are on its PubChem compound record.
Source: PubChem (PUG-REST)