💊 What it does
Myo-inositol is a naturally occurring sugar alcohol that acts as a secondary messenger in insulin signalling and is involved in neurotransmitter function (particularly serotonin and dopamine). The strongest clinical evidence is for PCOS (polycystic ovary syndrome) — myo-inositol at 2-4 g/day improves insulin sensitivity, restores ovulation, reduces androgens, and improves hormonal profiles in PCOS, with an evidence base comparable to metformin. There is also growing evidence for gestational diabetes prevention, anxiety reduction (at higher doses of 12-18 g/day), and OCD.
👤 Who needs it
Women with PCOS — this is the primary evidence-based application and one of the strongest natural supplement evidence bases for any condition. Pregnant women at risk of gestational diabetes. People with anxiety or OCD who have not responded to other approaches. Those with insulin resistance.
🥦 Food sources first
Inositol is found in fruits (particularly citrus), beans, grains, and nuts. Cantaloupe melon, oranges, grapefruit, almonds, and wholegrains are good sources. However, therapeutic doses (2-4 g/day for PCOS) are far above what is achievable from diet alone.
🗓 When to supplement
For PCOS — the evidence is strong and it is recommended by several European fertility societies. For gestational diabetes risk reduction. For anxiety at higher doses (under supervision). Consistent use over at least 3 months needed to assess effects on PCOS.
🏷 Best form to look for
Myo-inositol is the primary active form. D-chiro-inositol combined with myo-inositol at a 40:1 ratio (myo:DCI) is used specifically for PCOS — this ratio mirrors the body's natural production. Powder form is cost-effective for the higher doses needed.
⏰ When to take it
Twice daily with meals for PCOS — consistency matters more than specific timing. For anxiety: spread throughout the day.