Direct Answer
Thymosin Alpha-1 (thymalfasin) is a 28-amino-acid immunomodulatory peptide, approved in some countries and studied in trials for sepsis and hepatitis.
Summary Table
Evidence Level
Moderate
AI Summary
Thymosin Alpha-1 (thymalfasin) is a synthetic 28-amino-acid immunomodulatory peptide. Evidence is moderate: it is approved in a number of countries (as Zadaxin) for indications including chronic hepatitis B and immune support, and it has been evaluated in randomized controlled trials for severe sepsis (for example the ETASS trial and the larger phase 3 TESTS trial). It is not FDA-approved in the United States. Reported tolerability is generally favorable, but results across sepsis trials have been mixed, and effects are indication-specific.
Key Information
Classification
Key Takeaways
- Thymosin Alpha-1 (thymalfasin) is an immunomodulatory 28-amino-acid peptide approved in some countries (not the US)
- Randomized trials in severe sepsis (ETASS, TESTS) have produced mixed results
- Benefit is indication-specific; regulatory status varies by country
Scientific Overview
In Plain English
Thymosin Alpha-1 (also called thymalfasin) is a peptide that influences the immune system. It is an approved medicine in some countries for conditions like chronic hepatitis B and has been tested in randomized trials for severe sepsis. It is not approved in the US. Trial results in sepsis have been mixed.
Scientific Details
Thymosin Alpha-1 (thymalfasin) is a synthetic, N-terminally acetylated 28-amino-acid peptide with immunomodulatory activity, including effects on T-cell function and innate immune signaling. It is approved in several countries for chronic hepatitis B and as an immune adjunct. In severe sepsis it has been evaluated in randomized controlled trials, including the single-blind ETASS trial and the multicenter, double-blind phase 3 TESTS trial; results across trials have been mixed, and it is not FDA-approved in the United States.
How It Works
Thymosin Alpha-1 is described as an immunomodulator associated with enhancement of T-cell and dendritic-cell function and modulation of innate immune signaling (including Toll-like receptor pathways). These mechanisms are characterized in laboratory studies and supported by clinical trials in specific indications.
Mechanism of Action
Immunomodulation
human
Thymosin Alpha-1 is associated with enhanced T-cell and dendritic-cell function and modulation of innate immune signaling.
Evidence Level
Human Evidence
Approved in several countries for chronic hepatitis B and immune support. Randomized controlled trials in severe sepsis (ETASS; the phase 3 TESTS trial) have evaluated immunomodulatory use, with mixed results across trials.
Animal Evidence
Preclinical work characterized immunomodulatory pharmacology.
Limitations
Not FDA-approved in the US; efficacy is indication-specific and, in sepsis, results across randomized trials have been inconsistent. Approval and evidence vary by country.
Why This Grade
Graded moderate: supported by approvals in some countries and multiple randomized controlled trials in sepsis and hepatitis, but with mixed trial results, indication-specific benefit, and no US FDA approval.
References
- The efficacy and safety of thymosin alpha1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial. BMJ.Human Studydoi:10.1136/bmj-2024-082583 →
- The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Critical Care.Human Studydoi:10.1186/cc11932 →
- Thymosin alpha-1. American Journal of Health-System Pharmacy.Reviewdoi:10.1093/ajhp/58.10.886 →
Alternative Names
- Thymalfasin
- Zadaxin
- Tα1
- TA1
Risks & Safety
- Not FDA-approved in the United States; regulatory status and quality assurance vary by country
- Injection-site reactions have been reported; tolerability is generally described as favorable in trials
- Efficacy in sepsis is not consistently established across randomized trials
- Material sold by research-chemical vendors is not the regulated product and is not quality-controlled
Claim Boundaries
ION BLUE is an educational research aggregator. This content summarizes published scientific literature. It is not medically reviewed, is not medical advice, and is not a recommendation to use any substance. Some peptides discussed are approved in certain countries; others are research chemicals not approved for human use. Consult a licensed healthcare provider. This entry summarizes research and approvals that vary by country and is not medical advice or a recommendation to obtain or use thymosin alpha-1.
This page summarizes published research and is for informational purposes only; it is not medical advice.