Thymosin alpha-1

Name: Thymosin alpha-1: uses, evidence and safety
Creator: Cited Peptides Editorial

Also called Thymalfasin, Zadaxin

Immune support and as an add-on in infections and cancer, mainly outside the US.

By Cited Peptides Editorial Updated 2026-10-10 Medical review pending

This page has not yet been reviewed by a credentialed medical professional. It is educational and is not medical advice.

Thymosin alpha-1: key facts

Evidence level Human trials
Approved as a medicineYes: Authorized as a medicine in some countries; not in the US
Randomized trials on PubMed39
Papers on PubMed622
Trials testing it (ClinicalTrials.gov)6+
In tested sportCheck the current WADA Prohibited List

In one sentence: Thymosin alpha-1 is an approved medicine in some form (authorized as a medicine in some countries; not in the US). Its strongest evidence is human trials, with 39 randomized trials on PubMed that mention it.

What the evidence says

Human trials exist for infections and cancer, with mixed results.

Key studies

Randomized trials Listed on PubMed as randomized trials that mention it. Some only measure it rather than test it as a treatment.

Randomized Controlled Trial2024 A Prospective and Randomized Control Study on Effects of Thymalfasin for Injection on Perioperative Immune Function and Long-term Prognosis of Patients with Colorectal Cancer Biotechnol Genet Eng Rev PMID 37248723 → Multicenter Study, Randomized Controlled Trial2015 A multicenter, randomized, observation-controlled clinical trial to evaluate the efficacy and safety of thymalfasin adjuvant therapy in patients with HBV-related HCC after curative resection - first announcement of the protocol Expert Opin Biol Ther PMID 26094695 → Clinical Trial, Randomized Controlled Trial2004 Thymalfasin for the treatment of chronic hepatitis B Expert Rev Anti Infect Ther PMID 15482167 → Randomized Controlled Trial2011 Thymosin alpha 1 is associated with improved cellular immunity and reduced infection rate in severe acute pancreatitis patients in a double-blind randomized control study Inflammation PMID 20549321 → Randomized Controlled Trial2008 Thymosin alpha 1 provides short-term and long-term benefits in the reimplantation of avulsed teeth: a double-blind randomized control pilot study Am J Emerg Med PMID 18534287 →

Reviews Summaries of other studies.

Review2001 Thymosin alpha-1 Am J Health Syst Pharm PMID 11381492 → Review1992 Thymic endocrinology Int J Immunopharmacol PMID 1618588 → Research Support, Non-U.S. Gov't, Review2007 beta-Thymosins Ann N Y Acad Sci PMID 17468232 → Review1994 T-cell adjuvants Int J Immunopharmacol PMID 7806429 →

Other notable papers The most relevant other papers on PubMed.

Review2025 Aging and Thymosin Alpha-1 Int J Mol Sci PMID 41373628 → Editorial, Research Support, Non-U.S. Gov't2015 Thymosin alpha-1 treatment in chronic hepatitis B Expert Opin Biol Ther PMID 25640173 → Research Support, Non-U.S. Gov't2024 Thymosin α1 reverses oncolytic adenovirus-induced M2 polarization of macrophages to improve antitumor immunity and therapeutic efficacy Cell Rep Med PMID 39357524 → Review2016 Immune Modulation with Thymosin Alpha 1 Treatment Vitam Horm PMID 27450734 →

See its full evidence profile and newest papers →

Clinical trials

CompletedPhase 4 Thymosin Alpha 1 in the Prevention of Pancreatic Infection Following Acute Necrotizing Pancreatitis 508 people · Weiqin Li NCT02473406 → Status unknownPhase 4 Immunotherapy for Elderly Patients With Chronic Osteoporotic Pain 100 people · RenJi Hospital NCT04524169 → CompletedPhase 4 Efficacy Study of Thymosin alpha1 & Pegylated Interferon-alpha2a to Treat Chronic Hepatitis B 52 people · Seoul National University Hospital NCT00291616 → Status unknownPhase 3 Experimental Trial of rhIFNα Nasal Drops to Prevent 2019-nCOV in Medical Staff 2,944 people · Shanghai Jiao Tong University School of Medicine NCT04320238 → CompletedPhase 3 Thymosin Alpha-1 in Combination With Peg-Interferon Alfa- 2a and Ribavirin for the Therapy of Chronic Hepatitis C Nonresponsive to the Combination of IFN and Ribavirin. 552 people · sigma-tau i.f.r. S.p.A. NCT01178996 → CompletedPhase 3 Thymosin Plus PEG-Interferon in Hepatitis C Patients With Cirrhosis Who Did Not Respond to Interferon or Interferon Plus Ribavirin 500 people · SciClone Pharmaceuticals NCT00039962 →

Search all trials live →

Where it fits

GoalPeptides for immune support ComparisonKPV vs Thymosin alpha-1

Common questions

Is Thymosin alpha-1 approved?

Authorized as a medicine in some countries; not in the US.

Has Thymosin alpha-1 been tested in people?

39 randomized trials on PubMed mention it. Human trials exist for infections and cancer, with mixed results.

Is Thymosin alpha-1 allowed in sport?

Check the current WADA Prohibited List; unapproved substances can be banned under its catch-all category.

This is a short, data-driven profile. Study and trial lists come from PubMed and ClinicalTrials.gov and are refreshed periodically. "What people use it for" describes common claims, not recommendations. Educational only, not medical advice.