Inositol for Insulin Resistance
Inositol consistently improves short-term insulin-resistance markers such as HOMA-IR and fasting insulin across several trials, but the evidence rests entirely on surrogate measures of low certainty, so it is best viewed as a promising adjunct rather than a proven treatment for insulin resistance.
Why this grade7-layer evidence engine
Inositol earns a Preliminary (B) grade because the direction of effect is consistent across several meta-analyses. A 2025 GRADE-assessed review of 18 RCTs (PMID 41163174, n=898) found it lowered HOMA-IR (WMD -1.21) and fasting insulin (-4.74 microU/mL), and an earlier PCOS meta-analysis (PMID 29042448, n=496) reported similar reductions. A 2022 meta-analysis (PMID 35889788, n=1321) also found 4 g/day myo-inositol cut gestational-diabetes incidence by roughly 70% (RR 0.30).
The grade stays at B rather than higher for three reasons. Every measured benefit is a surrogate marker, not a hard clinical endpoint; the 2024 International PCOS Guideline meta-analysis (PMID 38163998, n=2230) rated certainty Very Low, called the evidence limited and inconclusive, and found no advantage over metformin; and the large NiPPeR RCT (PMID 33782086, n=1729) found no glycemic benefit when inositol was started preconception in a general population, suggesting the effect depends heavily on who takes it and when.
Regulators and clinics offer no endorsement that would lift the grade. The FDA treats inositol only as a GRAS food nutrient, the UK NHS notes the Inofolic combination helped PCOS metabolic markers in initial studies but does not recommend it as first-line, and WHO/Codex recognizes it solely as an infant-formula nutrient. Mayo Clinic and Harvard Health maintain no inositol fact sheet and professional societies are silent, hence published with warning.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.633
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (4 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status