What does Thymosin alpha-1 do? Benefits and evidence

Thymosin alpha-1 is a synthetic immune-signaling peptide approved in Singapore for hepatitis B and, with interferon, hepatitis C, but not in the US. Large sepsis and hepatitis C trials found no clear benefit; hepatitis B evidence remains uncertain. Immune reactions and unregulated injection quality are key concerns.

• Zadaxin is approved in Singapore for patients with chronic hepatitis B, and with interferon for hepatitis C, but not in the US. (Studied in a trial)
• In a small hepatitis B trial, six months of dosing gave a delayed virus response, though overall evidence is very uncertain. (Studied in a trial)
• Some users report fewer allergy symptoms and infections; others report feeling worse for a long time. (Reported by users)

Uses in the sources

• Zadaxin is approved in Singapore for chronic hepatitis B and, with interferon, hepatitis C. These overseas approvals are not FDA or EMA approvals. (Clinician-published) (source)
• Studied as an add-on in sepsis. The largest blinded trial found 28-day deaths of 23.4% with TA1 versus 24.1% placebo. (Studied in a trial) (source)
• Studied in hospitalized COVID-19 and dialysis patients. Trials are small, and reviews conflict; prevention and recovery benefits remain unproven. (Studied in a trial) (source)
• Studied with cancer therapy and vaccines. Immune-test or short-term response changes do not establish longer survival or fewer infections. (Studied in a trial) (source)
• People report use for long COVID, ME/CFS and allergies. Reports include both improvement and prolonged worsening. (Reported by users) (source)