Ann Intern Med

Trial finds no benefit of metformin or ursodiol for treating long COVID

March 9, 2026

A double‑blind, placebo‑controlled randomized trial conducted in South Korea evaluated whether a 2‑week course of metformin (uptitrated to 1500 mg/day) or ursodeoxycholic acid (UDCA) (900 mg/day) improved symptoms of postacute sequelae of SARS‑CoV‑2 infection (PASC) in adults with an index score ≥12. Among 396 participants (median age, 36 years; 72% women) randomized 1:1:1 to metformin, UDCA, or placebo, recovery rates at 8 weeks were similar across groups: 63.6%, 68.2%, and 68.2%, respectively. Mean improvements in PASC scores were nearly identical, with no significant differences vs. placebo (metformin, -10.05; UDCA, -10.62; placebo, -10.43).

Clinical takeaway: For patients with ongoing long‑COVID symptoms, metformin and UDCA should not be recommended as treatment based on current evidence; focus instead on symptom‑directed management and referral to multidisciplinary long‑COVID care when available.

Source:

Lim SY, et al. (2026, March 3). Ann Intern Med. Neither Metformin nor Ursodeoxycholic Acid Effectively Treats Postacute Sequelae of COVID-19: A Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/41771135/