Peptide Graded

Thymosin alpha-1

Does Thymosin alpha-1 work?

Partly: hepatitis B trials of 98 to 316 people, none for the immune-boosting uses it is sold for.

BSome human evidenceNot approvedas of 2026-10-27

Thymosin alpha-1 has several randomized trials in chronic hepatitis B (98 and 316 patients) and a meta-analysis of five trials with 353 patients showing delayed viral suppression, which is the approved use abroad. The 1,106-patient TESTS phase 3 trial in sepsis found no mortality benefit. The general immune-boosting use it is sold for in the US has no controlled trials, so the compound grades B on its hepatitis B evidence and D on the wellness claims. 2131415

In a 1998 randomized trial, 98 patients with chronic hepatitis B received a 26-week or 52-week course of thymosin alpha-1, or no treatment. Researchers assessed them 18 months after entry. Complete virological response means loss of hepatitis B virus DNA and e antigen. It occurred in 41 percent of the 26-week group versus 9 percent of controls. Responses kept building after treatment stopped. A Japanese randomized trial had 316 patients and compared two doses for 24 weeks. A year after therapy ended, about 23 percent had cleared e antigen. Liver enzymes had returned to normal in 36 percent. 214

A 2001 meta-analysis pooled five randomized trials (353 patients). It found no advantage over placebo at the end of treatment. At six months there was a trend. At 12 months after stopping, the odds ratio for virological response was significant at 2.67. Liver enzyme normalization did not differ at any point. 13

Evidence checklist

  • Randomised controlled trial Randomized hepatitis B trials, sepsis trial
  • Human study over 100 people TESTS enrolled 1,106 adults
  • More than one research group Trials in several countries
  • Clinical outcomes, not surrogate markers Sepsis mortality: no benefit
  • Human safety data beyond case reports Mild events across trials

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Citations

  1. Garaci 2009, Expert Opin Biol Ther: From lab to bedside, emerging clinical applications of thymosin alpha 1 pubmed.ncbi.nlm.nih.gov
  2. Chien 1998, Hepatology: Efficacy of thymosin alpha1 in chronic hepatitis B, randomized controlled trial pubmed.ncbi.nlm.nih.gov
  3. Wu 2013, Critical Care: Thymosin alpha1 in severe sepsis, randomized trial (ETASS) doi.org
  4. Liu 2025, BMJ: Thymosin alpha1 for sepsis (TESTS), phase 3 trial doi.org
  5. Iino 2005, J Viral Hepat: Thymosin alpha-1 in Japanese patients with chronic hepatitis B doi.org
  6. 2025, Front Cell Infect Microbiol: Efficacy of thymosin alpha1 for sepsis, systematic review and meta-analysis doi.org
  7. FDA: Certain bulk drug substances for use in compounding may present significant safety risks fda.gov
  8. Mannherz 2009, Cell Motil Cytoskeleton: The beta-thymosins, intracellular and extracellular activities pubmed.ncbi.nlm.nih.gov
  9. Chan 2004, Expert Rev Anti Infect Ther: Thymalfasin for chronic hepatitis B pubmed.ncbi.nlm.nih.gov
  10. Ren 2011, Microb Cell Fact: Production of N-acetylated thymosin alpha1 in E. coli pubmed.ncbi.nlm.nih.gov
  11. Romani 2006, Blood: Thymosin alpha1 activates dendritic cell tryptophan catabolism pubmed.ncbi.nlm.nih.gov
  12. 2026, Peptides: Thymosin beta 4, an emerging therapeutic candidate for kidney diseases pubmed.ncbi.nlm.nih.gov
  13. Chan 2001, Aliment Pharmacol Ther: Thymosin in chronic hepatitis B, meta-analysis pubmed.ncbi.nlm.nih.gov
  14. Iino 2005, J Viral Hepat: Thymosin alpha-1 in Japanese patients with chronic hepatitis B, randomized trial pubmed.ncbi.nlm.nih.gov
  15. Liu 2025, BMJ: Thymosin alpha1 for sepsis (TESTS), multicentre phase 3 trial pubmed.ncbi.nlm.nih.gov
  16. FDA: Pharmacy Compounding Advisory Committee minutes, December 2024 fda.gov

Reference information only, not medical advice. Drawn from the Thymosin alpha-1 article, fact-checked against the cited sources. No dosing anywhere on this site.