BCAA / Branched-Chain Amino Acids for Liver Cirrhosis
In people with cirrhosis, oral branched-chain amino acids (BCAAs) consistently ease hepatic encephalopathy and may improve nutritional measures, but they have not been shown to extend survival, and the underlying evidence is of low-to-moderate certainty. They are best viewed as an adjunct to standard care (such as lactulose and rifaximin), not a stand-alone treatment.
Why this grade7-layer evidence engine
This earns a Preliminary (B) grade because the efficacy signal is real and consistent but limited in scope. Two Cochrane systematic reviews (PMID 26377410, 2015; PMID 41542879, 2026) both found that BCAAs improve hepatic encephalopathy (relative risk 0.73 and 0.79), and an earlier review (PMID 23739310) reported a number-needed-to-treat of about 5, with overt encephalopathy responding far better (RR 3.26) than minimal forms (RR 1.32).
The grade stays at B rather than higher because the benefit does not extend to what matters most: every meta-analysis, including a 2022 supplementation review (PMID 35500317), found no significant effect on all-cause mortality, and the 2026 Cochrane update downgraded the certainty for survival to 'very low.' Two randomized trials (PMID 12806613; PMID 16206505) did show fewer composite complications and better event-free survival (OR 0.43; HR 0.67), but one was open-label and the other used a non-ideal comparator. Nausea and vomiting were markedly more common (RR 5.56).
Authorities are split, which fits a cautious read. Hepatology specialty societies (AASLD, EASL) and Mayo Clinic support BCAAs as adjunctive or maintenance nutritional therapy, while the FDA classifies them only as a GRAS nutrient supplement and the EU EFSA has rejected related health claims; the NHS and WHO do not address this use.
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 = 0.681
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 1 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