Legal status · United States
Is TUDCA legal in the United States?
Written by Aaron CuhaReviewed Sep 2026
Direct answer
TUDCA can be sold in the United States as a supplement or cosmetic ingredient, classified as "Sold as a supplement". That is not drug approval: FDA has not evaluated any health claim, and injectable or "research use only" versions fall outside supplement rules, so that label does not make human use lawful. On the evidence, 5 human studies are cited on its profile.
TUDCA in the United States at a glance
| Classification | Sold as a supplement |
|---|---|
| Note | Sold as a dietary supplement. The combination product containing it was approved for ALS and then withdrawn from the market by its sponsor after a failed phase 3 trial. Its parent compound, ursodeoxycholic acid, is a prescription medicine with its own entry on this site. |
| FDA approval status | Not approved as a single agent. A fixed combination of sodium phenylbutyrate and taurursodiol was FDA-approved for ALS and then voluntarily withdrawn by its sponsor after the phase 3 PHOENIX trial showed no change on the primary functional endpoint. TUDCA on its own is sold as a dietary supplement. |
| Human studies cited | 5 of 6 citations on the profile |
| Reviewed | Sep 2026 |
Classification and note come from the TUDCA profile, checked against U.S. Food and Drug Administration (FDA) listings at the reviewed date.
What this means
- 01
TUDCA can be sold in the United States as a supplement, food or cosmetic ingredient under the classification above, without drug approval.
- 02
Supplement status means FDA has not evaluated any health claim; manufacturers are responsible for safety and labeling, and quality varies by product.
- 03
Injectable or "research use only" versions are not supplements. That label does not make human use lawful, and injectables fall under medicines rules.
What TUDCA is
Twenty obese adults, four weeks: hepatic and muscle insulin sensitivity rose about 30 percent on a clamp, while adipose tissue insulin sensitivity and the endoplasmic reticulum stress markers the drug was meant to fix did not change. In ALS the phase 3 trial of TUDCA combined with sodium phenylbutyrate missed its endpoint and the approved product was voluntarily withdrawn from the market.
TUDCA is the taurine conjugate of ursodeoxycholic acid, which has its own entry on this site. The two are not interchangeable, and supplement marketing routinely treats them as though they were.
Mechanism: A hydrophilic bile acid that acts as a chemical chaperone, stabilising protein folding and reducing endoplasmic reticulum stress, and separately raising the threshold for mitochondrial permeability transition so that less cytochrome c is released and less apoptosis occurs. Conjugation with taurine increases water solubility and changes how the molecule is handled in the enterohepatic circulation relative to unconjugated ursodeoxycholic acid, which is why the two are studied separately.
Regulatory history: Not approved as a single agent. A fixed combination of sodium phenylbutyrate and taurursodiol was FDA-approved for ALS and then voluntarily withdrawn by its sponsor after the phase 3 PHOENIX trial showed no change on the primary functional endpoint. TUDCA on its own is sold as a dietary supplement.
How FDA treats this kind of product
Approves prescription drugs by indication and polices unapproved products, including peptides sold online. Compounding pharmacies may prepare some compounds under a prescription when the FDA places them on a permitted bulk-substances category.
The classification above is the The Longevity Archive reading of U.S. Food and Drug Administration listings for TUDCA at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.
TUDCA in other countries
Frequently asked questions
Is TUDCA legal in the United States?
TUDCA can be sold in the United States as a supplement or cosmetic ingredient, classified as "Sold as a supplement". That is not drug approval: FDA has not evaluated any health claim, and injectable or "research use only" versions fall outside supplement rules, so that label does not make human use lawful. On the evidence, 5 human studies are cited on its profile. Note: Sold as a dietary supplement. The combination product containing it was approved for ALS and then withdrawn from the market by its sponsor after a failed phase 3 trial. Its parent compound, ursodeoxycholic acid, is a prescription medicine with its own entry on this site.
Can I buy TUDCA in the United States?
Yes, in supplement or cosmetic form. In the United States TUDCA is classified as "Sold as a supplement", so oral, topical or cosmetic products can be sold under supplement rules. Injectable versions and products labeled "research use only" are not supplements and are not approved for human use. Note: Sold as a dietary supplement. The combination product containing it was approved for ALS and then withdrawn from the market by its sponsor after a failed phase 3 trial. Its parent compound, ursodeoxycholic acid, is a prescription medicine with its own entry on this site.
Is TUDCA FDA approved?
No. FDA status: Not approved as a single agent. A fixed combination of sodium phenylbutyrate and taurursodiol was FDA-approved for ALS and then voluntarily withdrawn by its sponsor after the phase 3 PHOENIX trial showed no change on the primary functional endpoint. TUDCA on its own is sold as a dietary supplement.. Current US classification: "Sold as a supplement". On the evidence, 5 human studies are cited on its profile.
Related compounds in the United States
Full research profile
Mechanism, cited studies, FDA status and the full legal summary for TUDCA live on its compound profile.
TUDCA profileThis page is general information about the regulatory status of TUDCA in the United States, current as of Sep 2026. It is not legal advice, and classifications change; check U.S. Food and Drug Administration directly or consult a lawyer for a specific situation. Educational use only. This database summarizes published research. It is not medical advice and contains no dosing protocols or recommendations for personal use. The Longevity Archive has no vendor relationships and does not recommend where to buy anything.