Myo-Inositol Supplements Guide (2026): PCOS Evidence, the 40:1 Ratio & Dose
Myo-inositol is the best-evidenced supplement for PCOS. Randomized trials show it improves insulin sensitivity, restores ovulation, and lowers androgens in many women — often compared to metformin but far better tolerated. The dose that was actually studied is 2 g twice daily (4 g total), and the trials that combined it with D-chiro-inositol used the physiological 40:1 myo-to-D-chiro ratio — a detail most bottles get wrong. Below: the evidence, the ratio, and dosing.
About our data
Every comparison uses clinical evidence from PubMed systematic reviews, product label data from the NIH Dietary Supplement Label Database, and third-party certifications (USP, NSF). Products are ranked by cost per clinically-effective dose. See our methodology and editorial standards.