TUDCA for NAFLD / MASLD

Verdict: Unproven for fatty liver in humans

There is currently no reliable human evidence that TUDCA improves NAFLD/MASLD: not a single completed clinical trial has tested it against liver fat, inflammation, or fibrosis, so any liver-health claims on supplement labels run well ahead of the science.

U ⚫ U Unverified Disputed

🔬Why this grade7-layer evidence engine

The grade is Unverified and Disputed because the directly applicable human data are essentially absent. The only relevant clinical trial (Kars 2010, PMID 20522594) randomized just 20 obese adults to TUDCA for four weeks and measured insulin sensitivity, not a fatty-liver outcome. Hepatic and muscle insulin sensitivity rose about 30%, but this is a surrogate for insulin resistance, and the trial found no change in ER-stress markers, which undercuts the chemical-chaperone mechanism that is meant to protect the liver.

Every NAFLD-specific efficacy signal comes from mice. Rodent studies report less steatohepatitis and fibrosis (PMID 24865256), a better gut barrier (PMID 29139555), and reduced hepatic fat via microbiota and bile-acid pathways (PMID 39193771). These are promising mechanistically but do not establish a human effect, and the closely related drug UDCA failed to improve liver histology in NASH trials.

Authorities reinforce caution rather than endorsement. The FDA recognizes TUDCA only as a drug for certain cholestatic liver diseases, and the WHO assigns it a drug name (ursodoxicoltaurine), not a supplement claim; the NHS lists it merely as an ALS trial agent. No major clinic or liver society (Mayo, Cleveland Clinic, Harvard, AASLD) recommends it for NAFLD. For fatty liver, weight loss and a Mediterranean diet remain the evidence-based first steps.

⚖️

Scoring transparency

All scores computed by a 7-layer evidence engine — fully auditable
Raw score 0.46
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
U · Disputed
Confidence
67%
Broadly consistent
Evidence level
E7
Single small RCT

How strongly each layer supports this effect

lower = less supportive
L11 AI re-checkIndependent read
0.20
L2 PubMedPrimary literature
0.45
L1 ExamineGlobal benchmark
0.50
L3 MechanismPlausibility
0.50
L5 Clinical bodiesAuthoritative stance
0.50
Against Mixed Supports
View the full decision path (audit trail)
  1. compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.455
  2. tier_from_score — 依分數區間映射至 tier letter
  3. apply_hec_rules — 無高階證據可裁決
  4. tier_strict_requirement_check — | C→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
  5. detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
  6. decide_status — 依 tier + dispute 結果決定 status

📄PubMed studies (4)L2 · primary research & systematic reviews

Tauroursodeoxycholic acid may improve liver and muscle but not adipose tissue insulin sensitivity in obese men and women
PMID: 20522594 2010 RCT (double-blind) n = 20
Finding: Hepatic and skeletal-muscle insulin sensitivity increased by ~30% after TUDCA but not after placebo; TUDCA increased muscle insulin signaling (phosphorylated IRS and Akt). Adipose tissue insulin sensitivity did not improve. Markers of ER stress in muscle and adipose tissue did not change after either treatment.
🟠 Limited quality Government Effect size: ~30% increase in hepatic and muscle insulin sensitivity (P<0.05); no change in adipose insulin sensitivity
View on PubMed
Tauroursodeoxycholic acid attenuates progression of steatohepatitis in mice fed a methionine-choline-deficient diet
PMID: 24865256 2014 Animal Study
Finding: TUDCA significantly reduced hepatic injury and histological fibrosis in both early and late intervention groups by reducing ER stress and suppressing apoptosis; hepatic triglyceride content was unchanged. Animal model only — not human evidence.
Government Effect size: Reduced ER stress markers and hepatocyte apoptosis; reduced fibrosis (qualitative, mouse)
View on PubMed
Tauroursodeoxycholic acid inhibits intestinal inflammation and barrier disruption in mice with non-alcoholic fatty liver disease
PMID: 29139555 2018 Animal Study
Finding: TUDCA attenuated progression of HFD-induced NAFLD by reducing gut inflammation, improving intestinal barrier function, decreasing intestinal fat transport, and modulating microbiota composition. Animal model only — not human evidence.
Government Effect size: Qualitative attenuation of NAFLD progression via gut-liver axis (mouse)
View on PubMed
Tauroursodeoxycholic Acid Improves Nonalcoholic Fatty Liver Disease by Regulating Gut Microbiota and Bile Acid Metabolism
PMID: 39193771 2024 Animal Study
Finding: TUDCA reduced obesity and hepatic lipid buildup, enhanced intestinal barrier function and microbial balance (increased Allobaculum and Bifidobacterium), and modulated bile acid metabolism via FXR and CYP7A1. Animal model only — not human evidence.
Effect size: Qualitative reduction in hepatic lipid accumulation (mouse)
View on PubMed

🏛️Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …

L4a US FDA
Cautious
TUDCA is a US Food and Drug Administration-approved hydrophilic bile acid for the treatment of certain cholestatic liver diseases source↗
L4b EU EFSA
Against
L4d TW TFDA / 衛福部
Against
含URSO(Ursodeoxycholic acid,去氧熊膽酸)成分之單方製劑統一為醫師處方用藥,適應症統一為「膽固醇系膽結石之溶解、原發性膽道肝硬化(primary biliary cirrhosis, PBC)之肝功能改善」。 source↗
L5e Specialty Society (condition-mapped)
Not addressed
PMID 100% verifiedevery citation checked via NCBI Entrez
🔬4 PubMed studiesindependently re-checked by multiple sub-agents
engine_version: v1.0 claim_id: CLM-COND-nafld-INT-tudca-001 繁體中文版 →