TUDCA_Dosage, benefits & legal status
Also known as tauroursodeoxycholic acid, taurursodiol, ursodoxicoltaurine, Tudcabil
A bile acid sold for liver support, with an approval history worth reading.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is TUDCA?
Plain language first. The technical label stays, but it never stands alone.Overview
It helps bile flow and takes strain off liver cells, which is why people take it alongside things that are hard on the liver.
TUDCA is tauroursodeoxycholic acid, the taurine conjugate of ursodeoxycholic acid, a water-loving bile acid that reduces endoplasmic reticulum stress and blocks the mitochondrial pathway to cell death.
What it's used for
An oral bile acid taken as on-cycle liver support, and studied for a much wider set of conditions than it is approved for.
How does TUDCA work?
What it does in the body, and where.TUDCA is a bile acid the body already makes, in small amounts.
- 01It shifts the bile acid pool toward the gentler formsBile acids sit on a scale from water-loving to fat-loving. The fat-loving ones damage cell membranes. TUDCA is at the water-loving end.
- 02It reduces stress in the endoplasmic reticulumThis is the part of the cell that folds proteins. When it backs up, the cell starts a self-destruct sequence. TUDCA acts as a chemical chaperone and eases that backlog.
- 03It interferes with the mitochondrial route to cell deathThat mechanism is behind the interest in neurons and retinal cells, not only liver cells.
- 04None of that is the same as proof it protects a healthy liverThe human data comes from people with liver disease. Whether it does anything measurable for someone taking an oral compound that raises liver enzymes has not been tested.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Cholestatic liver disease and cholesterol gallstones, where it is a licensed medicine in parts of EuropeClinical use
- ALS, as half of a combination product that was approved and then withdrawnInvestigational
- Insulin sensitivity and metabolic healthEarly research
- Protecting retinal cells and neurons under stressEarly research
- Liver support alongside oral compounds that raise liver enzymesResearch only
How much, and do you cycle it?
The range, and whether you take breaks.500 up to 2,000 mg per day, daily, often split into two doses. Continuous in the trialsTrial dose
Human trials dose it daily for months without a planned break. The on-and-off use tied to an oral cycle is a community pattern, and no study has looked at whether it matters.
How long does it stay in the body?
The half-life, and where the figure comes from.Not a useful figure hereNo figure
TUDCA joins a bile acid pool the body recycles through the gut and liver many times a day, so a plasma half-life does not describe how long it is doing anything. Trials dose it twice a day for that reason rather than because of a measured clearance figure.
You can compare this against the whole library to see where it sits.
What does it cost?
Typical dose and cost, in plain numbers.TUDCA is not injected
It is taken by mouth (oral). Supplement capsules are usually 250 or 500 mg and the common self-directed range is 500 to 1,000 mg a day. Human trials have gone much higher: the ALS and multiple sclerosis trials used 1 g twice daily, so 2,000 mg a day. There is no US label to check any of this against.
TUDCA starts at $32.48 across 2 vendors.
3 listings, last read Aug 27, 2026. Shipping and card fees are not included.
How do you store it?
Before mixing, and after.Room temperature. Cool, dry, out of light.
TUDCA is taken as a pill or capsule. Keep it in its original container at room temperature, away from heat, humidity, and direct sun. No fridge or mixing needed. Check the expiration date on the bottle.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Complete biliary obstruction, where increasing bile flow is the wrong direction
- Pregnancy and breastfeeding, on the basis of absent data rather than known harm
- Any existing liver disease, which needs a diagnosis rather than a supplement
Stop and get help
- Yellowing of the skin or eyes, dark urine or pale stools
- Severe or persistent right-sided abdominal pain
- Diarrhoea severe enough to cause dehydration
- Signs of an allergic reaction such as face or throat swelling, hives, or trouble breathing
Common effects
- Diarrhoea or loose stools
- Mild stomach upset
- Nausea, usually settling with food
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is TUDCA approved?
And where the numbers on this page come from.Not as a medicine. TUDCA is sold without a prescription as a supplement or cosmetic ingredient, which is a different thing from being approved as a drug. It is approved in Italy, but not in the United States.
- Approval statusOTC / supplement
- RouteBy mouth (oral)
- CheckedAugust 2026
- Approved outside the USItaly: Licensed in Europe since 1991 for cholesterol gallstones and chronic cholestatic liver disease, sold in Italy as Tudcabil and exported as Taurolite.This does not change the United States position above.
What has happened recently
Sold in the US as a dietary supplement, with no FDA approval for any use on its own. The molecule does have an approval history, and it is not the one vendors describe. Under the name taurursodiol it was one half of Relyvrio, a fixed combination with sodium phenylbutyrate that the FDA approved on 29 September 2022 for ALS on the strength of a single phase 2 trial. The confirmatory phase 3 trial, PHOENIX, missed both its primary and its secondary endpoints. The company reported that to the FDA on 30 April 2024, stopped marketing on 31 October 2024, and the approval was formally withdrawn on 29 August 2025. That approval belonged to a two-ingredient product and to one disease, and it no longer exists.
You can compare this against the whole library, or read how to check a seller.
- DoseFrom product labeling and published use.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
- Reviewed24 August 2026
What else is like TUDCA?
Others in Longevity and energy, side by side.If you're weighing TUDCA, it's worth reading Urolithin A, NMN, and Nicotinamide Riboside (NR) in the same class.
A bile acid sold for liver support, with an approval history worth reading.
- Dose
- 500 up to 2,000 mg per day
- How often
- Daily, often split into two doses
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- Dose
- 500 up to 1,000 mg per day
- How often
- Daily
The NAD+ precursor the FDA banned, then un-banned on a technicality.
- Dose
- 250 up to 1,000 mg per day
- How often
- Daily
The NAD+ precursor that kept its paperwork in order.
- Dose
- 300 up to 1,000 mg per day
- How often
- Daily
10What these words mean
Show glossary +
What these words mean
- 503A and 503B
- The two kinds of compounding pharmacy in US law. A 503A pharmacy prepares medicine for one named patient. A 503B outsourcing facility makes larger batches under stricter manufacturing rules.
- Agonist
- Something that switches a receptor on. The opposite is an antagonist. It blocks the receptor instead.
- Amino acid
- The building blocks that link together in a chain to make a peptide or a protein. The order they sit in is what makes one peptide different from another.
- Amylin
- A hormone released alongside insulin that slows the stomach emptying and reduces appetite. Several weight loss compounds copy it.
- Analog
- A compound built to copy a natural one with small deliberate changes, usually so it lasts longer or holds onto its target more tightly.
- Animal study
- Research done in rats, mice or other animals. Most findings do not repeat in people, so an animal result is a reason to keep looking. It is not a reason to act.
- Antibody
- A large immune protein, far bigger than a peptide, engineered to lock onto one specific target. These are made by drug companies and are not sold as research powders.
- Bacteriostatic water
- Sterile water with a tiny amount of preservative, used to mix powdered peptides.
- Banned in drug-tested sport
- Prohibited by the World Anti-Doping Agency (WADA); using it can disqualify a competing athlete.
- Bioavailability
- How much of a dose actually reaches your bloodstream. Most peptides survive stomach acid badly, so most of them are injected instead of swallowed.
- Bioregulator
- Very short peptides from a Russian research tradition, usually two to four amino acids long, sold for supporting a specific organ. Human evidence is thin and most of it is published in Russian.
- Blend
- One vial holding more than one compound, mixed together by the seller. Working out a dose means working out each ingredient separately, because they are rarely present in equal amounts.
- Boxed warning
- The most serious warning the FDA puts on a drug label, printed inside a black border. It flags a risk considered severe enough to sit above everything else on the label.
- Bulks list
- The FDA's list of ingredients that compounding pharmacies are allowed to use. A substance can sit under review on it for years without anything being decided either way.
- Certificate of analysis (COA)
- A lab report on a batch of product. It only means something if it names the batch you actually received, comes from an independent lab, and can be checked with that lab.
- Clinical trial
- A study that gives a treatment to people under a written plan and measures what happens. It is the only kind of evidence that can show something works in humans.
- Compounding
- A licensed pharmacy preparing a medicine to order. Being allowed to compound something is not the same as the FDA approving it, and the two get mixed up constantly.
- Concentration
- How strong the mixed peptide is, in milligrams per milliliter (mg/mL). More water makes it weaker; less water makes it stronger.
- Cycle
- A stretch of time using a compound followed by a break. Most cycling patterns come from community practice. Very few have been tested.
- DAC
- Short for Drug Affinity Complex. An attachment added to a peptide so it grabs onto a blood protein and stays in the body for days instead of minutes.
- Dead space
- The small amount of liquid left sitting inside the needle and hub after you inject. On very small doses it can be a real share of what you meant to take.
- Dilute
- Adding more liquid to make a mix weaker. The amount of peptide in the vial does not change. It is just spread through more water, so each draw is bigger.
- Endpoint
- The result a trial said in advance that it would measure. A study can be reported as positive and still have missed the endpoint it set out to hit.
- FDA approved
- Reviewed by the FDA and cleared for a specific use, in a specific form, at a specific dose. Approval for one use is not approval for another, and approval in another country is not approval here.
- Fragment
- A short piece cut out of a larger natural protein. A fragment can behave very differently from the whole protein it came from, so evidence about one does not transfer to the other.
- Ghrelin
- The hunger hormone. Some growth hormone compounds work by copying it, so they can make you noticeably hungrier.
- GHRH
- A natural signal telling the pituitary gland to release growth hormone. Several compounds copy it.
- GHRP
- A second, separate signal that also triggers growth hormone release, through a different door than GHRH. This is why the two types are often used together.
- GLP-1
- A natural gut hormone that lowers appetite and blood sugar. Drugs that copy it, like semaglutide, are used for weight loss.
- Growth hormone secretagogue
- A compound that nudges your body to release more of its own growth hormone, rather than injecting the hormone itself.
- Half-life
- How long a compound stays active in your body. A longer half-life means you inject less often.
- HPLC
- A lab method that separates out everything in a sample so the amounts can be measured. It shows how much of the main ingredient is there. It does not confirm that the main ingredient is the right molecule.
- In vitro
- Done in a dish or a test tube, on cells outside a living body. It is the earliest kind of evidence there is.
- Injection site
- The spot on the body where you inject. Moving it around gives the skin and fat underneath time to recover between doses.
- Intramuscular (IM)
- An injection into a muscle, using a longer needle.
- Intravenous (IV)
- An injection into a vein. It needs training and equipment and is not something to do at home.
- Investigational
- Still being tested in clinical trials and not yet approved or legally sold for general use.
- Lyophilized
- Freeze-dried into a powder so it keeps longer. That is the white cake or dust in the bottom of an unmixed vial.
- Mass spectrometry
- A lab method that weighs molecules to confirm what they are. HPLC answers how much is in the sample. This answers what it is.
- mcg and mg
- Units of dose. 1 milligram (mg) equals 1,000 micrograms (mcg).
- Myostatin
- A natural brake on muscle growth. Several compounds are built to block it, though human results have been far smaller than the animal work suggested.
- Off-label
- A doctor prescribing an approved drug for something other than its approved use. This is legal and common, and it is different from a compound having no approval at all.
- Orphan drug designation
- A status given to treatments for rare conditions to make them worth developing. It is an incentive, not an approval, and a compound can hold it while being approved for nothing.
- PCAC
- The FDA advisory committee that reviews compounding ingredients. It recommends. It does not approve, and the FDA does not have to follow what it says.
- Peer review
- Other scientists checking a paper before a journal publishes it. It filters out some bad work. It does not make a finding true.
- Peptide vs small molecule
- A peptide is a short chain of amino acids. A few items here (like MK-677 or methylene blue) are small molecules, not true peptides, but people use them the same way.
- Placebo
- A dummy treatment given for comparison. Without one it is very hard to tell a real effect apart from expectation and time passing.
- Purity
- The share of a sample that is the intended compound, usually given as a percentage. A high purity number on the wrong molecule is still the wrong molecule.
- Randomized
- Deciding by chance who gets which treatment, so the two groups are comparable. Studies that skip this are much easier to read the wrong way.
- Receptor
- A docking point on a cell that a compound attaches to. If a cell has no matching receptor, the compound does nothing to it.
- Reconstitution
- Mixing a powdered peptide with liquid (bacteriostatic water) so it can be drawn into a syringe.
- Research only
- No approved dose or use in people. Sold for research and not reviewed by the FDA for safety or quality.
- Stack
- Using more than one compound at the same time. Almost no combinations have been tested together in people, so a stack is usually built on guesswork.
- Sterile water
- Water with nothing added to stop bacteria growing. It works for a single dose, but a vial mixed with it should not be kept and used again.
- Subcutaneous
- An injection just under the skin, into the fat layer, usually with a short, thin insulin needle.
- Titrate
- Starting at a low dose and increasing it slowly over time so your body adjusts and side effects stay mild.
- Trial phases
- The stages of human testing. Phase 1 checks safety in a small group, phase 2 looks for an effect, and phase 3 tests it against a comparison in a large group.
- Units (on the syringe)
- The marks on an insulin syringe. 100 units equals 1 mL. They measure how much liquid you draw, not the dose in milligrams.
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- Federal Register, withdrawal of approval of the Relyvrio new drug application(2025)Approval dates, the PHOENIX result, and the formal withdrawal on 29 August 2025.
- Trial protocol for TUDCA in ulcerative colitis, ClinicalTrials.gov(2019)TUDCA has been licensed in Europe for gallstones and chronic cholestatic liver disease since 1991.
- Kusaczuk, Cells, review of TUDCA molecular and cellular effects(2019)Chaperone activity, ER stress reduction, and the relationship to the approved parent drug UDCA.
Last reviewed 24 August 2026
Peptide Decoding is published by Decoded Sciences LLC. We take no payment from vendors for coverage, inclusion or ranking, and our affiliate relationships are disclosed in full.