Bitter Melon Peptide (mcIRBP-19 / MAP30) for Insulin Resistance
High-quality reviews of bitter melon for blood-sugar control point mostly the wrong way or come back inconclusive, and the standardized mcIRBP-19 peptide marketed for "insulin resistance" has never actually been tested against a direct measure of it. On current evidence this is a weak, disputed claim, not a reliable way to improve insulin sensitivity.
Why this grade7-layer evidence engine
The engine grades this Tier D (Counter-Evidence), disputed, because the strongest evidence does not converge. A 2025 GRADE meta-analysis (PMID 41280283) did report a favorable HOMA-IR effect (SMD -0.52, p=0.02), but it pooled whole bitter-melon preparations rather than the standardized peptide, and rated its own certainty low to very low. A 2024 systematic review (PMID 38274207, n=414) found no significant HbA1c or fasting-glucose effect and explicitly concluded the metabolic effect 'cannot be determined' - a direct conflict that drives the disputed status.
Crucially, the two human trials of the commercial mcIRBP-19 peptide (PMID 35140559; PMID 32354072) measured only HbA1c and fasting glucose and never reported HOMA-IR or insulin, so the 'insulin resistance' claim is an extrapolation from a cell-and-mouse mechanism study (PMID 26988505) plus surrogate endpoints. Both peptide trials are industry-funded, and the double-blind one (PMID 35140559) was only borderline overall (p~0.06), reaching significance solely in a post-hoc 29-person subgroup.
Authorities reinforce the cautious read. The US FDA issued a warning letter calling a bitter-melon diabetes supplement not generally recognized as safe and effective, and the NIH Office of Dietary Supplements states bitter-melon extracts have 'only a modest effect on serum glucose' with 'little or no effect' on fasting glucose or HbA1c. The WHO lists no recommendation, and EFSA, the NHS, Mayo, Cleveland Clinic, Harvard, and the ADA do not address it. There is also a real safety flag: additive hypoglycemia risk with diabetes drugs, and contraindication in pregnancy and lactation.
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 = 0.582
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 negative 主導 (2 negative > 0 positive)，下層 RCT 不能推翻
- apply_hec_override — HEC-1 高階證據 negative — 強制由 B 改為 D
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 1 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status