Effects of inositol in women with polycystic ovary syndrome: an umbrella review of meta-analyses from randomized controlled trials.
Level 1 - systematic review of randomized trials
Umbrella review synthesizing meta-analyses of randomized controlled trials
PubMed 41757236 · doi:10.3389/fendo.2026.1741509
What was done
This umbrella review searched four databases up to August 2025 to synthesize and evaluate meta-analyses of randomized controlled trials examining inositol for polycystic ovary syndrome (PCOS). Outcomes evaluated included hormonal profiles, glycolipid metabolism, anthropometrics, and reproductive outcomes. Methodological quality was appraised using AMSTAR-2, and evidence certainty was graded using GRADE.
What was found
Thirteen meta-analyses were included. AMSTAR-2 ratings classified 23.1% as high, 53.8% as low, and 23.1% as very low quality. Across 85 GRADE-evaluated evidence items, 0% were high quality, 18.9% were moderate, 40% were low, and 41.1% were very low quality. Compared to placebo or folic acid, inositol significantly reduced: - Luteinizing hormone: MD -3.43 IU/L (95% CI: -4.29 to -2.56, P < 0.00001) - Free testosterone: MD -0.02 nmol/L (95% CI: -0.02 to -0.01, P < 0.00001) - HOMA-IR: MD -1.14 (95% CI: -1.35 to -0.94, P < 0.00001) - Fasting insulin: MD -23.40 pmol/L (95% CI: -32.80 to -14.01, P < 0.00001) - Total testosterone, androstenedione, and triglycerides (numerical values not reported in abstract) Inositol significantly increased: - Sex hormone-binding globulin: MD 36.72 nmol/L (95% CI: 28.52 to 44.91, P < 0.00001) - Live birth rate: RR 2.29 (95% CI: 1.07 to 4.93, P = 0.03) - Ovulation rate: RR 2.75 (95% CI: 1.71 to 4.41, P < 0.0001) Compared to metformin, differences were non-significant for most parameters, except triglycerides and pregnancy rates. Subgroup analyses found myo-inositol (with or without folic acid) was superior for metabolic and reproductive outcomes, whereas D-chiro-inositol monotherapy showed inferior utility.
Why it matters
This review integrates secondary evidence showing inositol effectively improves endocrine, metabolic, and fertility parameters over placebo in PCOS, performing similarly to metformin across most outcomes while highlighting myo-inositol as the preferred subtype.
Limits
The abstract notes no high-certainty GRADE evidence (81.1% low or very low quality) and over 76% of included meta-analyses had low or very low AMSTAR-2 ratings. The total number of primary trial participants is not reported, and exact quantitative effect sizes for comparisons versus metformin and certain hormonal outcomes were omitted from the abstract.