Thymosin Alpha-1 is a research compound studied for its role in anti-aging & longevity research. This page covers mechanism of action, published studies, preclinical protocols, and analytical specifications.
Store lyophilized at -20°C. Reconstituted: 4°C, use within 28 days.
Reconstitution
Add 1ml bacteriostatic water per vial. Swirl gently to dissolve.
Mechanism of Action
Thymosin Alpha-1 (Tα1) is a 28-amino acid peptide naturally produced by thymic epithelial cells and secreted into the circulation to regulate immune function. It was first isolated from thymosin fraction 5 by Allan Goldstein at George Washington University in 1977. The clinical formulation — thymalfasin (Zadaxin) — has received regulatory approval in over 35 countries for hepatitis B, hepatitis C, and as an adjuvant in cancer treatment.
Toll-Like Receptor (TLR) Signalling: Tα1 activates dendritic cells and plasmacytoid dendritic cells (pDCs) through Toll-like receptor pathways, particularly TLR9 (CpG DNA recognition) and TLR7 (ssRNA recognition). TLR activation in dendritic cells triggers MyD88-NF-κB signalling, driving production of type I interferons (IFN-α, IFN-β), IL-12, and other cytokines essential for antiviral and anti-tumour immune activation.
T-Lymphocyte Differentiation and Activation: Tα1 promotes differentiation of naive T-cells toward Th1 (cellular immunity) phenotypes over Th2 (humoral immunity). It upregulates expression of T-cell activation markers including CD69 and increases cytotoxic T-lymphocyte (CTL) activity — the immune cells responsible for direct killing of virally infected and tumour cells.
MHC Class I Upregulation: Tα1 increases expression of major histocompatibility complex class I (MHC-I) molecules on tumour and virally infected cells, improving their recognition by cytotoxic T-lymphocytes. This mechanism is particularly relevant in cancer immunology research, where tumour immune evasion often involves MHC-I downregulation.
Anti-Inflammatory Balance: Despite its pro-immune activity, Tα1 also modulates inflammatory balance — suppressing excessive Th2-driven allergic responses and downregulating pro-inflammatory cytokines in sepsis models. This dual immunomodulatory profile has driven research in sepsis, autoimmunity, and COVID-19 contexts.
Research Applications
Antiviral Immune Research: The primary clinical application of thymalfasin (Zadaxin) is in hepatitis B and C — approved in Asia and Eastern Europe. Research models use Tα1 to study interferon production, CTL activation, and viral clearance mechanisms.
Cancer Immunology: Tα1’s MHC-I upregulation and CTL activation make it relevant in tumour immunology research, particularly in models examining peptide-based immune adjuvants and combination with checkpoint inhibitors.
Sepsis and Immunoparalysis Research: Clinical research has examined Tα1 in sepsis-induced immunoparalysis — a state of profound T-cell dysfunction in severe infection. Research models use Tα1 to study immune restoration in ex vivo sepsis models.
COVID-19 Research: Tα1 received emergency use approval in several countries during the COVID-19 pandemic as an immune adjuvant. Research examining Tα1’s effects on COVID-19 immune dysregulation (cytokine storm, lymphopenia) represents a recent high-volume research application.
Aging and Thymic Involution: Age-related thymic involution produces declining Tα1 levels, contributing to immunosenescence. Research uses Tα1 supplementation in aged animal models to examine whether thymic peptide restoration reverses immune aging phenotypes.
Key Published Research
Primary publications relevant to Thymosin Alpha-1 research. Full citations available via PubMed. QSC does not endorse or make claims based on this research.
Goldstein et al. (1977)
“Isolation of a Polypeptide from Thymosin with Biological Activity Characterized as Thymosin Alpha-1” — Proceedings of the National Academy of Sciences
Original isolation and characterisation of Thymosin Alpha-1, establishing its thymic origin and immunomodulatory activity.
Romani et al. (2004)
“Thymosin Alpha-1 Activates Dendritic Cells for Antifungal Th1 Resistance through Toll-Like Receptor Signalling” — Blood
Characterises the TLR-mediated dendritic cell activation mechanism for Tα1, establishing the molecular basis for its immunostimulatory activity.
Liu et al. (2020)
“Thymosin Alpha-1 Reduces the Mortality of Severe COVID-19 by Restoration of Lymphocytopenia and Attenuation of Cytokine Storm” — Frontiers in Immunology
Clinical study examining Tα1 in COVID-19 patients, documenting lymphocyte restoration and cytokine modulation outcomes.
48–72h culture; endpoints: HLA-DR expression, TNF-α production after LPS re-stimulation
In Vitro TLR Assay
0.1–100 ng/ml
Added to dendritic cell culture
18–24h; endpoints: IFN-α, IL-12, NF-κB activation by ELISA and reporter assay
Frequently Asked Questions
What is Thymosin Alpha-1?
Thymosin Alpha-1 (Tα1) is a 28-amino acid thymic peptide that activates dendritic cells and T-lymphocytes through Toll-like receptor signalling, promotes Th1 immune responses, and upregulates MHC class I expression. Clinical thymalfasin (Zadaxin) is approved for hepatitis B, hepatitis C, and cancer adjuvant therapy in over 35 countries.
Is Thymosin Alpha-1 the same as Thymosin Beta-4?
No — they are entirely different peptides with different sequences, origins, and mechanisms. Thymosin Alpha-1 is a 28-aa thymic immunomodulatory peptide. Thymosin Beta-4 is a 43-aa ubiquitous actin-binding protein studied for tissue repair (TB-500 is its research fragment). Both were originally isolated from thymosin fractions but are structurally and functionally distinct.
Has Thymosin Alpha-1 been used clinically?
Yes. Thymalfasin (Zadaxin, SciClone Pharmaceuticals) is approved in over 35 countries for chronic hepatitis B, hepatitis C, and as a vaccine adjuvant. It received emergency use in several countries during COVID-19. It is not FDA-approved in the US; QSC Thymosin Alpha-1 is for research use only.
How should Thymosin Alpha-1 be stored?
Lyophilized at -20°C. After reconstitution with bacteriostatic water, store at 4°C and use within 28 days.
What purity is QSC Thymosin Alpha-1?
≥99% by HPLC and mass spectrometry. COA on product page, verifiable via Janoshik.
Research Use Only: All products sold on qsc-usa.com are intended strictly for laboratory research purposes only. They are not approved for human consumption, veterinary use, or any other application. Researchers are responsible for understanding and complying with local regulations in their jurisdiction.
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