TUDCA (Tauroursodeoxycholic Acid)
Also known as: TUDCA, Tauroursodeoxycholic Acid, Tauroursodesoxycholsäure, UDCA, Ursodeoxycholic Acid
Bile acid used to protect the liver during oral steroid use — one of the few supplements in this field with a plausible mechanism and clinical data behind it.
Substance family
Vitamins, minerals, amino acids and enzymes. The recurring pattern: correcting an actual deficiency helps, supplementing beyond a normal level generally does not.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
This substance works against
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Alongside oral steroids
IntermediateDose
500–1000 mg / day
Frequency
Split into 2 doses, with meals
Cycle length
For the duration of the oral, plus 2–4 weeks after
The dose range with the best support. Below roughly 500 mg the evidence thins out considerably.
Elevated liver values without steroid use
MedicalDose
250–500 mg / day
Frequency
1–2× daily
Cycle length
Medically supervised
Elevated liver values belong investigated rather than supplemented. TUDCA lowers the numbers; it does not identify the cause.
Higher doses
AdvancedDose
> 1500 mg / day
Frequency
Split into 2–3 doses
Cycle length
—
No additional benefit is established above this range, and diarrhoea becomes common.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Mistaking it for a licence to extend an oral cycle
Countermeasure
This is the most consequential misunderstanding. TUDCA addresses cholestasischolestasisBile backing up in the liver because its flow is obstructed — the specific liver injury oral steroids cause. — the bile backup that 17-alpha-alkylated17-alpha-alkylatedA chemical modification that lets a steroid survive being swallowed — at the liver's expense. compounds cause — but it does not make a liver-toxic substance safe. Running methasterone for eight weeks instead of four because TUDCA is on board is exactly the wrong conclusion.
Problem
Falling liver values read as a resolved problem
Countermeasure
TUDCA can improve ALT and AST while the underlying strain continues. The numbers look better without the situation being better. Judge the cycle by its duration and dose, not by whether the supplement is flattening the readings.
Problem
Diarrhoea and digestive upset
Countermeasure
Dose-dependent and the most common complaint. Split the dose, take it with meals, reduce if it persists.
Problem
Interaction with cholesterol-lowering resins
Countermeasure
Bile acid sequestrants bind TUDCA in the gut and cancel it out. Space them several hours apart if both are being used.
Overview
TUDCA is a bile acid that occurs naturally in the human body in small amounts. It is the taurine-conjugated form of ursodeoxycholic acid, which is an approved medicine for cholestatic liver disease — meaning there is a genuine pharmacological basis here, not just supplement marketing.
In this field it is used alongside oral steroids, and the reason it fits is specific: the type of liver strain that 17-alpha-alkylated compounds cause is exactly the type TUDCA addresses.
Mechanism of Action
Oral steroids do not damage the liver primarily through cell death. They cause cholestasis — a backup of bile. Bile is produced in the liver and drains through small ducts; 17-alpha-alkylated compounds impair that transport, bile accumulates, and the accumulated bile acids damage liver cells from the inside.
This is why the classic warning signs are jaundice, dark urine and itching rather than pain. They are all consequences of bile that is not draining.
TUDCA is a hydrophilic bile acid, meaning it is far less aggressive to cells than the body's own hydrophobic bile acids. It displaces them from the pool and improves bile flow. The mechanism matches the problem — which is more than can be said for most supplements marketed for liver protection.
Milk thistle, by comparison, acts as an antioxidant and does not address bile transport at all. That difference explains why TUDCA has largely displaced it in this context.
Typical Context
TUDCA is taken at five hundred to a thousand milligrams daily, split across two doses with meals, for the duration of an oral compound and two to four weeks afterwards.
The point that matters more than the dose: what TUDCA does not do. It reduces one specific type of liver strain. It does not neutralise a 17-alpha-alkylated compound, and it does not extend the window in which one can safely be used. Anyone reasoning that four weeks of oxymetholone becomes six because TUDCA is running has drawn precisely the wrong conclusion from a real effect.
There is a second and subtler trap. TUDCA can lower ALT and AST while the underlying strain continues. The readings improve without the situation improving. If liver values are the metric used to decide whether a cycle can continue, a supplement that flattens those values removes the signal being relied on.
Side Effects & Risks
- Diarrhoea and digestive upset, dose-dependent
- Nausea at higher doses
- Interaction with bile acid sequestrants
- Rarely: headache
- Otherwise well tolerated even over months
Blood Work & Monitoring
- Liver values (ALT, AST, GGT, bilirubin) — before, during and after; bilirubin is the marker most specific to cholestasis
- Lipid profile (LDL, HDL, triglycerides) — as a baseline
Harm-Reduction Notes
- It reduces cholestatic strain; it does not make an oral compound safe
- Do not extend cycle duration because TUDCA is on board
- Falling liver values under TUDCA are not proof that the strain has stopped
- Take with meals and split the dose to limit digestive upset
- Continue for 2–4 weeks after the oral has been stopped
- Space several hours apart from any bile acid sequestrant
- Persistent jaundice, dark urine or itching need a doctor, not a higher dose
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Dietary supplementFreely available; not subject to pre-market approval. |
| EU / UK | Food supplementAvailable as a supplement; the related UDCA is a prescription medicine. |
| Most other jurisdictions | Freely available |
| Competitive sport | Not prohibited |