UDCA (ursodeoxycholic acid) is a bile acid that is normally present in small amounts in human bile. As a medicine it is called ursodiol, and in the US, Canada and the UK it is a prescription drug for gallstones and primary biliary cholangitis (PBC). This page covers UDCA as it is sold outside a prescription: as an over-the-counter (OTC) medicine in some Asian markets, and as “liver support” capsules marketed online, often to people taking oral anabolic steroids.
The most important fact for this use is regulatory. In the US, FDA guidance says that an ingredient approved as a new drug is generally excluded from the definition of a dietary supplement, and ursodiol has been an approved drug since 1987. No controlled trial has tested UDCA for preventing liver injury from anabolic steroids; the evidence consists of case reports with mixed results.
This page summarizes what regulators, the drug labels and published trials report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Class | Hydrophilic (water-attracting) bile acid; same molecule as the drug ursodiol |
| Prescription status | Prescription only in the US, Canada and the UK |
| OTC status | Registered OTC products in Hong Kong (10 products as of 2011); an OTC product line in South Korea, including low-dose combination products |
| US supplement status | FDA says ingredients approved as new drugs are generally excluded from the dietary supplement definition; ursodiol was approved in 1987 |
| Route | Oral capsules and tablets |
| Doses in labels and trials | Labeled prescription doses 8–15 mg/kg/day or 600 mg/day; 25–50 mg per dose in Korean OTC combination trials |
| Half-life | No plasma half-life on the US labels; bile levels reach steady state in about 3 weeks and fall to 5–10% of that within about 1 week of stopping |
| Steroid “liver protection” | No prevention trials; case reports only, with mixed results |
| WADA status | Not named on the 2026 Prohibited List |
The library has a separate page for ursodiol (UDCA), which covers the approved prescription drug, its labeled uses and the clinical trials in depth. TUDCA is the taurine-conjugated form, which is sold as a supplement in the US.
What it is
UDCA is a dihydroxy bile acid. The US labels note that it occurs in small amounts in normal human bile and in larger amounts in the bile of certain bear species (URSO label). Whether it is labeled as a prescription drug, an OTC medicine or a supplement, the active molecule is the same.
| Compound | Status | Library page |
|---|---|---|
| Ursodiol (UDCA) | FDA-approved prescription drug for gallstones and PBC | Ursodiol (UDCA) |
| UDCA | Same molecule, sold OTC in some countries and online as “liver support” | This page |
| TUDCA | UDCA conjugated with taurine; sold as a supplement in the US | TUDCA |
According to the URSO label, UDCA works mainly by replacing more toxic, hydrophobic (water-repelling) bile acids in the bile pool. It also protects the cells lining the bile ducts, inhibits programmed death of liver cells and increases bile flow. These mechanisms were established in cholestatic liver disease, meaning disease where bile flow is impaired.
How it works in the body
UDCA acts mainly in the liver, bile and gut rather than in the bloodstream. The US labels report these properties (ursodiol capsule label; URSO label):
| Parameter | What the labels report |
|---|---|
| Absorption | About 90% of a therapeutic dose absorbed in the small bowel (capsule label) |
| Circulation | Taken up by the liver from portal blood, conjugated, secreted into bile and reabsorbed many times |
| Share of bile acids | 30–50% of biliary and plasma bile acids at 13–15 mg/kg/day (URSO label) |
| Time to steady state in bile | About 3 weeks |
| Washout | Bile levels fall to about 5–10% of steady state about 1 week after stopping |
| Plasma half-life | Not given on either US label |
In a small Korean study, 30 overweight adults with raised ALT (an enzyme released by damaged liver cells) took UDCA 300 mg twice daily or vitamin E for 8 weeks. UDCA pharmacokinetics in this group were similar to those of healthy volunteers (Yoon et al., Clin Pharmacol Drug Dev 2021).
Regulatory status by region
UDCA’s status depends on the country and on how a product is labeled.
| Region | Status | Source |
|---|---|---|
| United States | Prescription drug (ursodiol); approved ingredients are generally excluded from the dietary supplement definition | FDA; 21 U.S.C. 321 |
| Canada | Prescription drug, authorized only for certain liver diseases; unauthorized imported UDCA products have been seized | Health Canada 2024 |
| United Kingdom | Prescription-only medicine (POM), for example Ursofalk | Ursofalk SmPC |
| Hong Kong | 10 OTC products containing UDCA were registered in 2011, 8 with UDCA as the only active ingredient | Hong Kong DH 2011 |
| South Korea | Sold as a prescription line and an OTC line, including combination products | Korea.net 2014 |
United States
FDA states that ingredients approved as new drugs are generally excluded from the definition of a dietary supplement. The exception is an ingredient that was marketed as a supplement or food before the drug approval (FDA). This rule is written into the Federal Food, Drug, and Cosmetic Act at section 201(ff)(3)(B) (21 U.S.C. 321).
Ursodiol was first approved as Actigall on December 31, 1987 (Drugs@FDA NDA 019594). We found no published FDA determination or warning letter that addresses UDCA supplements specifically. FDA also does not approve any dietary supplement before it is marketed. So products sold online as UDCA “supplements” have not been reviewed by FDA for content, dose or safety.
Canada
In June 2024 Health Canada seized Korean-labeled Festal Plus tablets from a store in Coquitlam, British Columbia. The labeling listed ursodiol, and the product was promoted as a digestive aid. Health Canada stated that ursodiol is a prescription drug in Canada, authorized only for certain liver diseases. It added that unauthorized products have not been assessed for safety, efficacy or quality, and may contain undeclared ingredients or lack the ingredients they claim (Health Canada 2024).
Hong Kong and South Korea
In 2011, Hong Kong’s Department of Health reported 10 registered OTC products containing UDCA. It gave the adult recommended dose for its approved uses as 6–15 mg/kg/day and warned against exceeding labeled doses (Hong Kong DH 2011).
In South Korea, Daewoong Pharmaceutical has sold UDCA as Ursa since 1961, when it was marketed as a liver “revitalization” supplement. A 2014 government news feature describes a prescription line and an OTC line, the latter including combination products (Korea.net 2014). The OTC products’ fatigue claims have been disputed by Korean pharmacists’ groups, which argued that UDCA’s established effect is on bile secretion rather than fatigue (Korea Times 2014).
What the research shows
Low-dose OTC combination products
Two Korean randomized, double-blind, placebo-controlled trials tested OTC-style products that combine low-dose UDCA with vitamins or other ingredients. Because the products contained several active ingredients, these trials cannot show what UDCA alone contributed.
| Trial | Product (per capsule) | Participants | Result |
|---|---|---|---|
| Kim et al., Chin Med J 2016 | UDCA 25 mg, taurine 300 mg, ginseng extract 50 mg, inositol 10 mg, thiamine 5 mg; twice daily for 4 weeks | Adults with physical fatigue and no significant liver disease (mean baseline ALT about 17 U/L); 72 vs 75 in the efficacy analysis | Fatigue score below the cutoff in 70.0% vs 50.9% on placebo (p = 0.019); ALT fell by 2.8 vs 0.9 U/L |
| Oh et al., Int J Clin Pract 2016 | UDCA 50 mg, thiamine 10 mg, riboflavin 5 mg; three times daily for 8 weeks | 168 fatigued adults with raised liver tests (under 5 times normal) and/or fatty liver | Fatigue score below the cutoff in 79.8% vs 45.7% on placebo (p under 0.05); ALT fell by 8.3 vs 0.8 U/L |
Fatigue was measured with the Checklist Individual Strength questionnaire, using a cutoff of 76 points. In both trials adverse events were similar on the product and on placebo, and no serious adverse events occurred. The ALT changes were small in absolute terms, and neither trial measured liver disease outcomes.
Raised liver enzymes and fatty liver
Lower liver enzymes on UDCA are well documented, but lower enzymes are not the same as a healthier liver:
- In a Korean double-blind trial, 135 patients with raised ALT (mostly from fatty liver or alcohol) took UDCA 300 mg/day or another liver drug, biphenyl dimethyl dicarboxylate, for 24 weeks. ALT normalized in 34.8% on UDCA vs 80.0% on the comparator. There was no placebo arm (Lee et al., Korean J Gastroenterol 2014).
- In the 30-person Korean study above, ALT fell on UDCA 600 mg/day over 8 weeks, but lipids and insulin sensitivity did not change (Yoon et al., Clin Pharmacol Drug Dev 2021).
- A 2-year US trial of prescription-dose UDCA (13–15 mg/kg/day) in fatty liver with inflammation found no benefit over placebo on liver biopsy. That trial is described on the ursodiol page.
Hong Kong’s health department made the same point in its 2011 alert: improved liver tests do not always correspond to improved liver disease (Hong Kong DH 2011).
Liver protection alongside oral steroids
No published trial has tested UDCA taken alongside oral 17α-alkylated steroids, such as oxymetholone, stanozolol or methasterone, to prevent liver injury. The evidence is limited to treatment after injury has occurred, in case reports.
A 2021 systematic review of UDCA in drug-induced liver injury (DILI) found 25 case reports and 8 case series, with no adequate randomized trial (Robles-Díaz et al., Front Pharmacol 2021). Six of the case reports in its table involved anabolic steroids:
| Outcome after UDCA | Cases | Steroids involved |
|---|---|---|
| Improvement reported | 2 | Several steroids including oxymetholone and stanozolol; nandrolone and stanozolol |
| No improvement | 4 | Desoxymethyltestosterone; stanozolol; stanozolol with trenbolone; methasterone |
In all 4 cases without improvement, jaundice persisted or worsened on UDCA, and the patients improved only after corticosteroids or plasma exchange. A 2020 review of 52 cases of steroid-induced liver injury reached a similar conclusion (Abeles et al., BMJ Open Gastroenterol 2020):
- 12 patients received UDCA alone and 12 received UDCA with corticosteroids; in 3 of those, corticosteroids were added because UDCA had “failed”.
- The authors noted that most cases resolve without specific treatment once the steroid is stopped, and that all treatment data come from uncontrolled case reports.
- Giving UDCA during recovery can also make it harder to assess what caused the injury.
A 2026 case report describes a 26-year-old man who developed severe cholestatic injury, with peak bilirubin of 24.6 mg/dL, after 4 weeks of oxymetholone 50 mg/day with injected testosterone. Both drugs were stopped on day 30 and UDCA was given as supportive care; by day 85, bilirubin had fallen by 91.5%. The authors stated that recovery could not be attributed to UDCA in an uncontrolled case (Taha et al., Case Reports Hepatol 2026).
About “liver support” on cycle. UDCA is often sold as a way to make oral steroids safer for the liver. The evidence does not show this. There are no prevention trials in steroid users, treatment reports are mixed, and lower liver enzymes on UDCA do not show that the underlying injury has stopped.
Prevention of liver injury from other drugs
The same 2021 review found four studies of UDCA for preventing liver injury from medical drugs (Robles-Díaz et al., Front Pharmacol 2021):
| Study | Drug | Finding |
|---|---|---|
| Randomized trial, 80 children with leukemia | Chemotherapy | No difference in liver fibrosis vs control |
| Pilot randomized open-label trial, 39 children with leukemia | Chemotherapy | A trend toward lower transaminases with UDCA |
| Retrospective study, 181 men with prostate cancer | Flutamide | Transaminase rises in 11.4% with UDCA 375 mg/day vs 32.4% without |
| Open-label pilot, 114 patients with Alzheimer disease | Tacrine | Normal ALT at the end in 93% of 14 UDCA patients vs 69% without |
None of these involved anabolic steroids, and only two were randomized. The review concluded that study designs do not allow a firm conclusion on UDCA’s efficacy in treating or preventing DILI.
Side effects and risks
Common side effects
At prescription doses, UDCA is generally well tolerated. In the US capsule-label trials, diarrhea was somewhat more common than on placebo (27.1% vs 21.4% in gallstone dissolution, 25.2% vs 20.9% in gallstone prevention) (ursodiol capsule label). The URSO label lists abdominal discomfort and pain, hair loss, diarrhea, nausea, itching and rash as the most common reactions (≥1%) in postmarketing and clinical experience (URSO label). Rates by trial are tabulated on the ursodiol page.
Liver tests, jaundice and high doses
The URSO label lists postmarketing reports of jaundice or worsening of existing jaundice. For prescribed use, it advises liver tests and bilirubin every month for the first 3 months and every 6 months after that. The UK Ursofalk label advises monitoring ALT, AST and GGT every 4 weeks for the first 3 months (Ursofalk SmPC).
Very high doses can cause harm in some liver diseases. Hong Kong’s 2011 alert, based on a Health Canada warning, reported that patients with primary sclerosing cholangitis taking twice the recommended dose had a 2.1-fold greater risk of death or liver transplant than those on placebo (Hong Kong DH 2011).
Enteroliths
Rare postmarketing reports describe enteroliths (hard masses in the intestine) that caused obstruction and needed surgery. They occurred in people with intestinal narrowing or slow transit (URSO label).
Interactions
Both US labels list the same interactions:
- Bile acid sequestrants (cholestyramine, colestipol) may reduce UDCA absorption.
- Aluminum-based antacids bind bile acids in vitro and may act the same way.
- Estrogens, oral contraceptives and clofibrate (and perhaps other lipid-lowering drugs) increase liver cholesterol secretion and may counteract UDCA’s effect on gallstones.
Who should not use it
The URSO label lists complete biliary obstruction and known hypersensitivity to ursodiol as contraindications. The UK label adds acute inflammation of the gallbladder or bile ducts, frequent biliary colic and calcified gallstones (Ursofalk SmPC). Jaundice or itching during oral steroid use is a sign of liver injury that needs medical assessment; the case reports above show it can progress despite UDCA.
Quality and contamination
We found no published independent testing of the UDCA content of products sold as supplements. Products sold outside the regulated drug supply carry the general risks Health Canada describes for unauthorized products: their safety, efficacy and quality have not been assessed, and they may contain undeclared ingredients or lack the stated active ingredient (Health Canada 2024). Prescription and licensed OTC products, by contrast, are manufactured to a regulator-approved specification.
Its US labels carry no controlled-substance schedule, and UDCA is not named on the WADA 2026 Prohibited List.
Key takeaways
- Same molecule as the drug ursodiol. UDCA sold OTC or online is chemically identical to the prescription drug covered on the ursodiol page.
- Regulatory status varies. It is prescription-only in the US, Canada and the UK, but has been sold OTC in Hong Kong and South Korea. In the US, FDA generally excludes approved drug ingredients from the dietary supplement category.
- OTC trial evidence is thin. Korean trials of low-dose combination products reported less fatigue and small ALT drops, but the products contained several ingredients and no disease outcomes were measured.
- No proof of “liver support” on cycle. No trial has tested UDCA for preventing steroid-related liver injury. In 4 of 6 published steroid cases treated with UDCA, jaundice persisted or worsened until other treatment was given.
- Lower enzymes are not the same as a healthier liver. UDCA lowers ALT, but regulators and trials note that this does not always reflect less liver damage.
- Quality is unverified outside licensed products. No independent testing of UDCA supplements has been published.
Sources
- Allergan. URSO 250 and URSO Forte (ursodiol) tablets prescribing information. DailyMed.
- Actavis Pharma. Ursodiol capsules USP, 300 mg, prescribing information. DailyMed.
- Dr Falk Pharma UK. Ursofalk 250mg Hard Capsules: Summary of Product Characteristics, revised November 2024. emc.
- Food and Drug Administration. Drugs@FDA: Actigall (ursodiol), NDA 019594. FDA.
- Food and Drug Administration. Questions and Answers on Dietary Supplements. FDA.
- Federal Food, Drug, and Cosmetic Act, section 201(ff), 21 U.S.C. 321(ff). Cornell LII.
- Health Canada. Unauthorized Korean-labelled Festal Plus tablets, seized from GD Health Town in Coquitlam, B.C., may pose serious health risks. June 28, 2024. Health Canada.
- Department of Health, Hong Kong. Safety alert on ursodeoxycholic acid containing drugs. December 6, 2011. Hong Kong DH.
- Korea.net. Ursa helps improve liver function for over 50 years. November 21, 2014. Korea.net.
- Nam HW. Ursa faces placebo allegations. The Korea Times. March 21, 2014. Korea Times.
- Kim KM, Kim MJ, Song SW, et al. Efficacy and Safety of “URSA Complex” in Subjects with Physical Fatigue: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial. Chin Med J (Engl). 2016;129(2):129–134. PubMed.
- Oh B, Choi WS, Park SB, et al. Efficacy and safety of ursodeoxycholic acid composite on fatigued patients with elevated liver function and/or fatty liver: a multi-centre, randomised, double-blinded, placebo-controlled trial. Int J Clin Pract. 2016;70(4):302–311. PubMed.
- Lee SH, Cheon GJ, Kim HS, et al. Comparison on the efficacy and safety of biphenyl dimethyl dicarboxylate and ursodeoxycholic acid in patients with abnormal alanine aminotransferase: multicenter, double-blinded, randomized, active-controlled clinical trial. Korean J Gastroenterol. 2014;64(1):31–39. PubMed.
- Yoon S, Lee H, Ji SC, et al. Pharmacokinetics and Pharmacodynamics of Ursodeoxycholic Acid in an Overweight Population With Abnormal Liver Function. Clin Pharmacol Drug Dev. 2021;10(1):68–77. PubMed.
- Robles-Díaz M, Nezic L, Vujic-Aleksic V, et al. Role of Ursodeoxycholic Acid in Treating and Preventing Idiosyncratic Drug-Induced Liver Injury. A Systematic Review. Front Pharmacol. 2021;12:744488. PubMed.
- Abeles RD, Foxton M, Khan S, et al. Androgenic anabolic steroid-induced liver injury: two case reports assessed for causality by the updated Roussel Uclaf Causality Assessment Method (RUCAM) score and a comprehensive review of the literature. BMJ Open Gastroenterol. 2020;7(1):e000549. PubMed.
- Taha HM, Khalifa BH, Hassan MY, et al. Oxymetholone-Associated Cholestatic Drug-Induced Liver Injury With Profound Hyperbilirubinaemia: A Longitudinal Case Report. Case Reports Hepatol. 2026;2026:2519455. PubMed.
- World Anti-Doping Agency. The 2026 Prohibited List. WADA 2026 Prohibited List.