TUDCA (tauroursodeoxycholic acid) is a water-soluble bile acid your body already makes in small amounts. Most people take it as a liver protector during anything that taxes the liver, oral steroid cycles, heavy drinking phases, long courses of hepatotoxic medications, or just chronically elevated ALT/AST on bloodwork. It's the supplement you reach for when you know you're putting your liver through something and you want to soften the damage.

It works by improving bile flow, swapping out the more toxic bile acids in your bile pool for milder ones, and calming the cellular stress response inside liver cells that drives them to die when they're overloaded. In humans, it consistently lowers ALT, AST, GGT, and ALP, the markers most people are actually watching. Beyond the liver, it shows up in research on insulin sensitivity, neurodegenerative disease, and gut health, but the liver story is where the evidence is strongest and where most people benefit.

Deep-dive

Dosage:

• General liver support / mildly elevated enzymes: 250-500 mg/day. Take with food. Enough for most people who just want background protection or are on something mildly hepatotoxic
• Oral steroid cycles (17α-alkylated compounds like Anadrol, Superdrol, Dianabol, Anavar, Halotestin): 500-1000 mg/day, split into two doses, run for the duration of the cycle and 2-4 weeks after. Higher end (1000-1500 mg) for harsher compounds or stacked orals
• Active cholestasis or significantly elevated ALT/AST (2-3x upper limit and above): 750-1500 mg/day in 2-3 divided doses. This is the dose range that mirrors the cirrhosis and PBC trials. If enzymes don't come down in 8-12 weeks, get a proper workup, supplements aren't a substitute for a diagnosis
• Insulin sensitivity / metabolic use: 1500-1750 mg/day, the dose used in the only positive human trial. Expensive and the evidence is thin outside that one study, most people are better served by training and diet for this purpose
• Timing: With meals improves tolerability, particularly the larger doses, since bile is naturally released with food. Some people split doses morning and evening to keep bile flow steady
• Stacking: Pairs well with NAC (600-1200 mg/day) for anyone on oral anabolics or otherwise loading the liver, the mechanisms are complementary (NAC supports glutathione, TUDCA handles bile acid pool and ER stress). Milk thistle is commonly stacked but the evidence is weaker. Don't stack TUDCA with cholestyramine or other bile acid sequestrants, they'll bind it before it works
• Cycling: Continuous use up to 6-12 months has been studied without serious issues. Beyond that, data thins out. Most people use it situationally (during a cycle, during a heavy drinking period, while on a hepatotoxic medication) rather than daily for life

Here's what you can expect:

For liver protection during a cycle or other hepatotoxic period, you won't feel anything subjectively. The point is what doesn't happen, you don't see ALT/AST climb the way they would otherwise, you don't get the upper-right-quadrant discomfort, dark urine, or itching that signals cholestasis kicking in. The benefit is visible on bloodwork, not in how you feel.

For people starting with already-elevated enzymes (fatty liver, post-cycle, recovering from alcohol, drug-induced), expect a measurable drop in ALT, AST, GGT, and ALP within 4-12 weeks at 750-1500 mg/day. The drop tends to be in the 30-50% range from baseline in the studied populations.

Some people report improved digestion of fats and reduced bloating after fatty meals, particularly those with sluggish bile flow, gallbladder removal, or low stomach acid. This is plausible mechanistically and shows up frequently in anecdotal reports, but isn't directly tested in trials.

Don't expect to feel sharper, more energetic, or different in mood. TUDCA isn't doing anything in the brain you'll notice. The neurodegeneration data is about slowing decline in disease, not enhancing cognition in healthy people.

Side effects & risks: