What is the best clinical use case for inositol (myo-inositol)?

From the Guidelines

Inositol is most effectively used clinically for treating polycystic ovary syndrome (PCOS), as evidenced by its potential to improve metabolic and reproductive deregulation in PCOS 1.

Key Considerations

• The recommended dosage for PCOS is typically 2-4 grams of myo-inositol daily, often combined with 50-100 mg of D-chiro-inositol in a 40:1 ratio, taken for at least 3-6 months to see benefits.
• Inositol works by enhancing insulin signaling pathways and improving cellular glucose uptake, which helps address the underlying metabolic disturbances in PCOS, as noted in studies on its role in managing cardiometabolic and reproductive deregulation 1.
• Patients should take inositol with meals to minimize mild gastrointestinal side effects like nausea or diarrhea that some may experience.
• While generally considered safe, patients should consult healthcare providers before starting inositol, especially if taking medications for diabetes, as it may enhance insulin sensitivity and require adjustment of other treatments.

Clinical Application

• Inositol may help with metabolic syndrome, insulin resistance, and certain mood disorders, in addition to its primary use in PCOS.
• The improvement in ovulation, menstrual regularity, and fertility, along with the potential reduction in androgen levels and insulin resistance, makes inositol a valuable treatment option for PCOS patients.
• Healthcare providers should be aware of the potential benefits and interactions of inositol when managing patients with PCOS or related conditions, considering the latest evidence from systematic reviews and meta-analyses 1.

From the Research

Clinical Use of Inositol

The best clinical use case for inositol appears to be in the treatment of Polycystic Ovary Syndrome (PCOS) due to its insulin-sensitizing effects and ability to improve metabolic and hormonal states.

• Inositol, particularly myo-inositol (MI) and D-chiro-inositol (DCI), has been shown to be effective in improving insulin sensitivity and restoring spontaneous ovulation in women with PCOS 2, 3, 4.
• The combination of MI and DCI may be more effective than either inositol species alone, with a suggested ratio of 40:1 (MI:DCI) being an optimal approach for the treatment of PCOS disorders 4, 5.
• Inositol may also have benefits for some metabolic measures and potential benefits for ovulation, although the evidence is limited and inconclusive 6.

Key Findings

• Myo-inositol is involved in follicular gonadotropin pathways and is a precursor of inositol triphosphate, a second messenger regulating many hormones such as TSH, FSH, and insulin 3, 4.
• D-chiro-inositol is synthetized by an insulin-dependent epimerase that converts myo-inositol into D-chiro-inositol and provides second messengers promoting glucose uptake and glycogen synthesis 4.
• The use of inositol in combination with other therapies, such as metformin and clomiphene, may enhance its effects on fertility in PCOS women seeking pregnancy 5.

Considerations

• The evidence supporting the use of inositol in the management of PCOS is limited and inconclusive, and clinicians and patients should consider the uncertainty of the evidence together with individual values and preferences when engaging in shared decision-making regarding the use of inositol for PCOS 6.
• Impaired intestinal transport may lead to unsuccessful inositol treatment, and new data on the use of alpha-lactalbumin to boost inositol absorption may be relevant 5.