Why Athletes Take Ursodeoxycholic Acid
Ursodeoxycholic acid, often shortened to UDCA or "urso", is a prescription medicine for certain liver and gallbladder conditions. In bodybuilding circles it has gained a reputation as a liver protector. Our editorial team examines what UDCA actually does, its licensed uses in the UK, what the evidence says about its use by athletes and why it is no guarantee of safety.
What ursodeoxycholic acid is
UDCA is a bile acid that occurs naturally in small amounts in human bile. It was historically identified in bear bile, which gave it its name, but medicinal UDCA is now produced synthetically.
In the UK, UDCA is a prescription-only medicine. It is licensed for dissolving certain cholesterol gallstones in people with a functioning gallbladder and for treating primary biliary cholangitis (PBC). For PBC, product information typically describes doses based on body weight, in the region of 12–16 mg/kg per day.
EASL clinical practice guidelines on cholestatic liver diseases recommend UDCA as first-line treatment for PBC, where it improves liver biochemistry and long-term outcomes in many patients.
It is also used in some other cholestatic conditions, such as intrahepatic cholestasis of pregnancy and cystic fibrosis-related liver disease, under specialist supervision.
How it works
UDCA is more hydrophilic, or water-loving, than many of the body’s natural bile acids. Hydrophobic bile acids can damage cell membranes when they accumulate, which happens in cholestasis — reduced bile flow.
Beuers summarised UDCA’s mechanisms: it shifts the bile acid pool towards less toxic forms, stimulates bile secretion by liver cells, protects cells against bile acid-induced apoptosis and may have immune-modulating effects.
Its gallstone effect is different: UDCA reduces cholesterol saturation of bile, allowing small cholesterol stones to dissolve slowly over months.
Crucially, these mechanisms are most relevant when bile flow is impaired. That is why athletes became interested in it in connection with oral anabolic steroids.
Why athletes became interested
Oral 17-alpha-alkylated anabolic steroids are well known to cause cholestatic liver injury, among other liver harms. Solimini and colleagues reviewed hepatotoxicity associated with illicit steroid use, including cholestasis, peliosis hepatis and liver tumours.
Because UDCA treats cholestasis in medical conditions, some users reason that it should protect against steroid-induced liver damage. Online forums often present it as an essential "support" product.
There are case reports of UDCA being used in the medical treatment of drug-induced cholestasis, including steroid-related cases, but there are no robust controlled trials showing that taking it alongside steroids prevents liver injury.
The American College of Gastroenterology guideline on idiosyncratic drug-induced liver injury notes that the cornerstone of management is stopping the offending agent; evidence for specific treatments, including UDCA, is limited.
This article does not give guidance on combining UDCA with anabolic steroids or other substances. The most reliable way to protect the liver is not to take hepatotoxic drugs.
Side effects, contraindications and false security
UDCA is generally well tolerated in licensed use. The most common side effect is loose stools or diarrhoea. Other effects listed in product information include abdominal pain and, rarely, itching or calcification of gallstones.
| Aspect | What is known | Implication |
|---|---|---|
| Common side effects | Diarrhoea, loose stools | Usually mild |
| Contraindications | Acute gallbladder or bile duct inflammation, blocked bile ducts, non-functioning gallbladder, frequent biliary colic | Medical assessment needed before use |
| Interactions | Bile acid sequestrants and some antacids reduce absorption; may affect ciclosporin levels | Pharmacist review advised |
| High doses in some conditions | A high-dose trial in primary sclerosing cholangitis showed harm | More is not better |
Lindor and colleagues found that high-dose UDCA in primary sclerosing cholangitis was associated with more serious adverse events than placebo. This finding is a reminder that the drug is not harmless simply because it is a bile acid.
Perhaps the biggest risk is false reassurance. Normal-looking enzymes while taking UDCA can mask ongoing injury, and UDCA does nothing for other steroid-related harms such as heart disease, blood clots, hormonal suppression or psychiatric effects.
Obtaining UDCA without a prescription also means no medical assessment of whether it is appropriate, no monitoring and uncertain product quality.
A medical approach to liver concerns
If you are worried about your liver — whether because of medicines, alcohol, weight or past substance use — the right step is assessment, not self-medication.
- Book a GP appointment and be open about everything you take.
- Ask for liver function tests, avoiding hard training for a few days beforehand.
- Report symptoms such as jaundice, itching, dark urine, pale stools or abdominal pain urgently.
- Follow specialist advice if a liver condition is diagnosed.
Doctors in the UK are bound by confidentiality, and knowing about substance use allows safer, more accurate care.
For licensed conditions such as PBC or gallstones, UDCA can be a valuable, well-studied medicine when prescribed and monitored appropriately.
Conclusions of the editorial team
Ursodeoxycholic acid is a prescription bile acid with clear licensed uses in primary biliary cholangitis and cholesterol gallstones.
Athletes’ interest stems from its role in cholestasis, but there is no solid evidence that it prevents liver damage from anabolic steroids, and it does nothing for their other harms.
It has side effects, contraindications and interactions, and can create false security. Medical assessment is the safer path.
Related articles cover blood tests while taking essential phospholipids, citrus bergamot and the liver, and infection risks from shared equipment.
References
- European Association for the Study of the Liver. EASL Clinical Practice Guidelines: management of cholestatic liver diseases. J Hepatol. 2009;51(2):237–267.
- Beuers U. Drug insight: mechanisms and sites of action of ursodeoxycholic acid in cholestasis. Nat Clin Pract Gastroenterol Hepatol. 2006;3(6):318–328.
- Lindor KD, Kowdley KV, Luketic VA, et al. High-dose ursodeoxycholic acid for the treatment of primary sclerosing cholangitis. Hepatology. 2009;50(3):808–814.
- Solimini R, Rotolo MC, Mastrobattista L, et al. Hepatotoxicity associated with illicit use of anabolic androgenic steroids in doping. Eur Rev Med Pharmacol Sci. 2017;21(1 Suppl):7–16.
- Chalasani NP, Maddur H, Russo MW, Wong RJ, Reddy KR. ACG Clinical Guideline: diagnosis and management of idiosyncratic drug-induced liver injury. Am J Gastroenterol. 2021;116(5):878–898.
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