Scientific Reference
Thymosin Alpha 1
Evidence profile: Controlled human evidence
Thymosin alpha 1 is a 28-residue peptide, acetylated at its N-terminus, first isolated from calf thymus extract and now made synthetically. It matches the N-terminal segment of a larger protein, prothymosin alpha, from which it is thought to be released by proteolytic processing; the synthetic form is also known as thymalfasin. The peptide is strongly acidic and, in water, largely unstructured. Its literature spans cell studies of immune signalling, animal infection and tumour models, and human clinical studies in chronic viral hepatitis, severe infection and vaccine response. Many of those clinical studies are small, and a defined cellular receptor has not been confirmed.
Mechanism of Action
Thymosin alpha 1 has no single confirmed receptor. Several studies have linked its activity to Toll-like receptor signalling, particularly TLR9 and TLR2 in dendritic cells, with downstream activation of pathways including NF-κB and p38 MAPK. In cell and animal models it has been reported to influence T-cell maturation, production of cytokines such as interleukin-2 and interferon-gamma, and natural killer cell activity. Structural studies report that it becomes partly helical in membrane-like environments, which has been proposed as relevant to how it interacts with cells, though this remains an open question.
Molecular Information
- Type: Acetylated thymic peptide
- Length: 28 amino acids
- Molecular weight: 3108.3 g/mol
- Molecular formula: C129H215N33O55
- CAS: 62304-98-7
Published Research
Treatment with thymosin alpha-1 increases fertilizing capacity of sperm of infertile men: a multicenter trial
Naz RK et al. · Archives of andrology · 1995 · Clinical
PMID 8579476 — View on PubMedThymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: a systematic review and meta-analysis
Tian Y et al. · Frontiers in immunology · 2025 · Review
PMID 40599771 — View on PubMedThymosin Alpha 1 Plus Routine Treatment for the Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis
Cao A et al. · Journal of the College of Physicians and Surgeons--Pakistan : JCPSP · 2024 · Review
PMID 39648386 — View on PubMedComprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials
Dinetz E et al. · Alternative therapies in health and medicine · 2024 · Review
PMID 38308608 — View on PubMedThe efficacy of thymosin alpha-1 therapy in moderate to critical COVID-19 patients: a systematic review, meta-analysis, and meta-regression
Soeroto AY et al. · Inflammopharmacology · 2023 · Review
PMID 37845598 — View on PubMed