What the evidence says. Graded mixed: TUDCA matches the prescription bile acid UDCA for primary biliary cholangitis, but a promising 34-patient ALS trial was not confirmed by the 336-patient TUDCA-ALS phase 3 or the 664-patient PHOENIX trial of TUDCA plus phenylbutyrate, and no human trial tests its longevity claims. (Mixed evidence: Conflicting results across studies; benefit uncertain.)
What is TUDCA?
TUDCA (Tauroursodeoxycholic acid) is a gut and immune supplement used for improves bile-flow liver markers (as effective as udca in pbc). NutriDex grades the human evidence as Mixed. TUDCA is a water-soluble bile acid — the taurine-bound form of ursodeoxycholic acid (UDCA), a prescription drug for bile-flow liver disease and originally the active part of bear bile. It is a prescription drug in Italy and China and a supplement in the US. In a 199-patient Chinese trial of primary biliary cholangitis, 76% on TUDCA versus 81% on UDCA achieved a >25% fall in the liver enzyme ALP, confirming similar efficacy. In 20 obese adults, 1,750 mg/day for 4 weeks raised liver and muscle insulin sensitivity by about 30%. Neurology is where hopes peaked and faded: a 2016 pilot in 34 ALS patients found 87% vs 43% 'responders', but the 18-month, 336-patient TUDCA-ALS phase 3 showed no benefit in 2024. The phenylbutyrate–TUDCA combination (Relyvrio/AMX0035) won approval after a 137-patient trial, then failed its 664-patient PHOENIX trial and was withdrawn. There is no human evidence for anti-ageing use.
Purported Benefits
✓Improves bile-flow liver markers (as effective as UDCA in PBC)
✓May raise liver and muscle insulin sensitivity (small trial)
✓Studied — and so far failed — as a neuroprotector in ALS
✓Marketed for 'liver detox' and longevity (unproven)
Dosing & Compounds
Typical Dose
Liver trials used 750 mg/day (250 mg three times daily) and ALS trials 1 g twice daily; supplements typically sell 250–500 mg capsules.
Active Compounds
Tauroursodeoxycholic acid (taurine-conjugated UDCA)Ursodeoxycholic acid (UDCA, its metabolite)
Safety & Cautions
⚠
TUDCA is generally well tolerated at 0.75–2 g/day; the main side effects are diarrhoea, loose stools and abdominal discomfort, occurring at similar rates to placebo in large trials. Like UDCA, it should not be used with blocked bile ducts, acute gallbladder inflammation or calcified gallstones without medical supervision. Bile-acid sequestrants (cholestyramine, colestipol) and aluminium antacids reduce its absorption, UDCA-class bile acids can raise ciclosporin levels, and oestrogens or fibrates may counteract its effect on bile. Supplement-grade products are not standardised, and there are no long-term safety data for healthy people taking it for 'longevity'. Educational only — always check with your doctor or pharmacist before combining TUDCA with any medicine.
TUDCA is most often taken for Improves bile-flow liver markers (as effective as UDCA in PBC), May raise liver and muscle insulin sensitivity (small trial), Studied — and so far failed — as a neuroprotector in ALS, Marketed for 'liver detox' and longevity (unproven). A bile acid that treats some liver disease; ALS hopes fell flat.
Does TUDCA work — what does the evidence say?
Mixed evidence. Conflicting results across studies; benefit uncertain. TUDCA is a water-soluble bile acid — the taurine-bound form of ursodeoxycholic acid (UDCA), a prescription drug for bile-flow liver disease and originally the active part of bear bile. It is a prescription drug in Italy and China and a supplement in the US. In a 199-patient Chinese trial of primary biliary cholangitis, 76% on TUDCA versus 81% on UDCA achieved a >25% fall in the liver enzyme ALP, confirming similar efficacy. In 20 obese adults, 1,750 mg/day for 4 weeks raised liver and muscle insulin sensitivity by about 30%. Neurology is where hopes peaked and faded: a 2016 pilot in 34 ALS patients found 87% vs 43% 'responders', but the 18-month, 336-patient TUDCA-ALS phase 3 showed no benefit in 2024. The phenylbutyrate–TUDCA combination (Relyvrio/AMX0035) won approval after a 137-patient trial, then failed its 664-patient PHOENIX trial and was withdrawn. There is no human evidence for anti-ageing use.
What is the typical dose of TUDCA?
Liver trials used 750 mg/day (250 mg three times daily) and ALS trials 1 g twice daily; supplements typically sell 250–500 mg capsules.
Is TUDCA safe? Any cautions or side effects?
TUDCA is generally well tolerated at 0.75–2 g/day; the main side effects are diarrhoea, loose stools and abdominal discomfort, occurring at similar rates to placebo in large trials. Like UDCA, it should not be used with blocked bile ducts, acute gallbladder inflammation or calcified gallstones without medical supervision. Bile-acid sequestrants (cholestyramine, colestipol) and aluminium antacids reduce its absorption, UDCA-class bile acids can raise ciclosporin levels, and oestrogens or fibrates may counteract its effect on bile. Supplement-grade products are not standardised, and there are no long-term safety data for healthy people taking it for 'longevity'.
How many studies support TUDCA?
NutriDex cites 9 sources for TUDCA, graded "Mixed".
Cite this page
APA
Peh, D. (2026). TUDCA (Tauroursodeoxycholic acid): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 18 Oct 2026, from https://nutridex.info/s/tudca
BibTeX
@misc{nutridex_tudca,
author = {Peh, Daryl},
title = {TUDCA (Tauroursodeoxycholic acid): Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/tudca},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-10-18}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.