Benefits
Cholestasis / Liver Support
Prescription ursodiol/UDCA (Actigall, Urso) is an established MEDICAL treatment for primary biliary cholangitis (PBC) — a diagnosed liver disease that requires physician management. TUDCA is used similarly as a drug in some countries, but the over-the-counter TUDCA supplement has not been shown in trials to treat PBC. TUDCA replaces toxic bile acids with hydrophilic versions, reduces hepatocyte injury. Direct human evidence for the TUDCA supplement itself is limited: its only controlled trial (Kars 2010, n=20, 4 weeks) measured insulin sensitivity rather than any liver-disease outcome, so general liver-support use rests largely on mechanism and on data borrowed from the prescription drug UDCA.
ER Stress Reduction (Endoplasmic Reticulum Stress)
TUDCA reduces ER stress and unfolded protein response — relevant for diabetes, neurodegeneration, fatty liver, and ischemia-reperfusion injury. Foundational mechanism distinguishes TUDCA from many liver supplements.
ALS / Neurodegenerative Disease Adjunct (Research)
AMX0035 (Relyvrio®) — TUDCA + sodium phenylbutyrate combination — was approved by FDA in 2022 for ALS based on CENTAUR trial showing slower disease progression. Withdrawn from market 2024 after Phase 3 confirmatory trial failed to show benefit. TUDCA's neuroprotective mechanism remains scientifically interesting; clinical translation for ALS is questionable.
Eye Health / Retinitis Pigmentosa Research
Animal models of retinitis pigmentosa show TUDCA reduces retinal cell apoptosis. 'Bear bile' traditionally used in TCM for eye conditions — modern TUDCA represents this lineage.
Gallstone Dissolution (Modest)
Gallstone dissolution is an established use of the PRESCRIPTION drug UDCA (ursodiol), given under medical supervision — not a demonstrated use of TUDCA supplements. Any similar effect of TUDCA is unproven.
Mechanism of action
Hydrophilic Bile Acid Substitution
TUDCA is a hydrophilic (water-soluble) bile acid — when added to the bile acid pool, it dilutes more toxic hydrophobic bile acids. Reduces hepatocyte membrane injury and apoptosis from bile acid toxicity. Foundational mechanism for cholestasis applications.
ER Stress / UPR Modulation
Reduces endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) — pathways activated in many disease states (diabetes, neurodegeneration, NAFLD). Acts as 'chemical chaperone' supporting protein folding.
Anti-Apoptotic Activity
Inhibits mitochondrial pathway of apoptosis — protects various cell types (hepatocytes, neurons, retinal cells) from programmed cell death. Mechanism involves Bcl-2 family modulation and caspase inhibition.
Anti-Inflammatory Effects
Reduces pro-inflammatory cytokine production via NF-κB modulation and other pathways. Contributes to liver-protective effects.
Clinical trials
Phase 2 clinical trial of AMX0035 (TUDCA 1 g + sodium phenylbutyrate 3 g, twice daily) vs placebo in 137 ALS patients for 24 weeks.
137 ALS patients.
Significantly slower disease progression (ALSFRS-R) vs placebo. Generated FDA approval (2022). However, Phase 3 confirmatory PHOENIX trial (2024) failed to show benefit; product withdrawn from market 2024.
Multiple trials of UDCA (and TUDCA) for PBC over decades.
PBC patients.
As a prescription drug (ursodiol/UDCA), an established treatment that significantly improves liver enzymes and may slow progression of PBC — a diagnosed disease requiring medical care, not a self-treated supplement indication. UDCA stronger evidence base; TUDCA used similarly in some countries.