TUDCA (Tauroursodeoxycholic Acid)
Liver and bile-flow support, relevant if stacking peptides with anything orally hepatotoxic.
What it is
Bile acid derivative. Improves bile flow, reduces ER stress in liver cells, and shows hepatoprotective effects in clinical trials. Originally a hepatology drug; now sold as a supplement.
Why peptide users take it
Most peptides aren't hepatotoxic on their own (injection, no first-pass), but users frequently stack with orals (MK-677, anastrozole, oral AAS) where liver support genuinely matters. Also relevant for GLP-1 users with pre-existing fatty liver, some evidence of benefit.
Pairs with these peptides
How it actually works
TUDCA is a hydrophilic bile acid. It displaces toxic hydrophobic bile acids from the liver, reducing the inflammation those compounds cause. Separately, it reduces stress on the endoplasmic reticulum (the protein-folding machinery) inside liver cells, and ER stress is one of the main pathways through which orals cause hepatotoxicity. Net effect: cleaner bile, less inflammation.
Dose
When to take
Signs you actually need this
- Elevated ALT/AST on bloodwork during an oral cycle
- Right-upper-quadrant fullness or mild discomfort
- Light-colored stools or yellow tint to skin/eyes (advanced, see a doctor)
- Fatigue with normal blood sugar and electrolytes
Signs it's working
- ALT/AST trending down on follow up labs (4–8 weeks)
- RUQ discomfort resolves
- Energy stabilizes if cholestasis was the cause
Common mistakes
- Starting at 500 mg and getting diarrhea, start at 250 mg
- Treating it as 'liver insurance' for peptides that don't actually need it (BPC, TB-500, GHK), waste of money
- Skipping bloodwork, TUDCA's effect on you is invisible without ALT/AST trending data
- Taking it with gallstones / biliary obstruction, increases bile flow, can worsen blockage
Where to buy
Editorial picks. Brand selection follows the quality criteria (USP/NSF or third-party COA where possible). Affiliate links , see the disclosure at the bottom of /supplements.
Caveats
- Diarrhea is the most common side effect; start at 250 mg.
- If you have gallstones or biliary obstruction, talk to a doctor, TUDCA increases bile flow.
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