Thymosin Alpha-1
A 28‑amino‑acid thymic peptide (thymalfasin) associated with immune modulation.
Key Research Properties:
| SKU: | thymosin-alpha-1 |
|---|---|
| Purity: | >99% (HPLC Verified) |
| Form: | Lyophilized Powder |
| Storage: | Store at -20°C |
| CAS Number: | 62304-98-7 |
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What is Thymosin Alpha-1?
Thymosin Alpha-1 (Tα1, also known as thymalfasin) is a 28-amino acid peptide originally isolated from thymus gland tissue that plays a critical role in T-cell maturation and immune system regulation[1]. It is one of the most clinically validated immunomodulatory peptides, with regulatory approval in over 35 countries for treating chronic hepatitis B, hepatitis C, and as an adjuvant in cancer immunotherapy[2].
Biochemical Properties
- Sequence: 28 amino acids (Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN-OH)
- Molecular Weight: 3,108 Da
- Structure: Acetylated N-terminus; α-helical secondary structure
- Origin: Originally isolated from thymus fraction 5 (thymosin fraction 5)
- Synthesis: Now produced via recombinant DNA technology or solid-phase peptide synthesis
Primary Functions
- T-Cell Maturation: Promotes differentiation of T-cell precursors in thymus
- Immune Enhancement: Augments T-helper cell (Th1) responses; increases IL-2, IFN-γ production
- Antiviral Activity: Enhances host defense against viral infections (HBV, HCV, HIV)
- Adjuvant Effects: Boosts vaccine responses; enhances tumor immunity
- Anti-inflammatory: Modulates excessive inflammation while maintaining protective immunity
Discovery & Clinical Development
Thymosin Alpha-1 was discovered in the 1970s by Dr. Allan Goldstein and colleagues at George Washington University as part of research into thymic hormones and immune function[3]. The peptide was identified as the active component of "Thymosin Fraction 5," a crude thymic extract with immune-stimulating properties.
Key Milestones:
- 1972: Discovery of thymosin fractions with immunostimulatory activity
- 1977: Isolation and sequencing of Thymosin Alpha-1 from thymosin fraction 5
- 1980s: Preclinical studies demonstrate immune-enhancing effects in immunodeficiency models
- 1991: First regulatory approval (Italy) for chronic hepatitis B treatment
- 1990s-2000s: Expansion of approvals across Asia, Europe, Latin America for hepatitis and cancer
- 2000s-present: Extensive clinical trials in sepsis, vaccines, COVID-19, and immunosenescence
Regulatory Status & Clinical Use
Approved Indications
35+ Countries: Chronic hepatitis B, chronic hepatitis C
China, Philippines, others: Cancer adjuvant therapy (melanoma, lung, liver cancer)
Various Countries: HIV/AIDS support, immunodeficiency, vaccine enhancement
Clinical Formulation
Brand Name: Zadaxin® (SciClone Pharmaceuticals)
Route: Subcutaneous injection
Dosing: Typically 1.6 mg SC twice weekly
Duration: Varies by indication (12-52 weeks)
U.S. Status
FDA Status: Not currently approved (multiple trials completed; approval not pursued commercially)
Availability: Research use; off-label clinical use by some physicians
Ongoing Trials: COVID-19, sepsis, vaccine adjuvant applications
Mechanism of Action
Thymosin Alpha-1 exerts its immunomodulatory effects through multiple mechanisms involving T-cell differentiation, cytokine production, dendritic cell maturation, and direct antiviral activity[4]. Unlike many immunostimulants, Tα1 enhances protective immunity while dampening excessive inflammation, making it a true immune "modulator" rather than simple "stimulant."
T-Cell Development & Maturation
Thymic T-Cell Differentiation
Primary Mechanism: Thymosin Alpha-1 was originally identified as a thymic hormone that promotes the differentiation of T-cell precursors into mature, functional T-lymphocytes.
Effects on T-Cell Populations:
- CD4+ T-Helper Cells: Increases CD4+ cell counts and functionality; particularly enhances Th1 (cell-mediated immunity) responses
- CD8+ Cytotoxic T-Cells: Enhances cytotoxic T-lymphocyte (CTL) activity against viral infections and tumor cells
- Regulatory T-Cells (Tregs): Modulates Treg function to balance immune activation and prevent autoimmunity
- T-Cell Receptor Expression: Upregulates TCR expression and signaling capacity
- Thymic Selection: Influences positive and negative selection processes in thymus
Cytokine & Immune Mediator Regulation
Cytokine Network Modulation
Thymosin Alpha-1 orchestrates immune responses by modulating cytokine production, shifting the balance toward protective Th1 responses while preventing excessive inflammation.
↑ Increased Cytokines (Pro-Th1):
- IL-2 (Interleukin-2): T-cell growth factor; essential for T-cell proliferation and CTL generation
- IFN-γ (Interferon-gamma): Activates macrophages; enhances antiviral and antitumor immunity
- IL-12: Drives Th1 differentiation; critical for cell-mediated immunity
- IL-7: T-cell survival and homeostasis
- IFN-α/β: Antiviral interferons; innate immunity activation
↓ Decreased Cytokines (Anti-inflammatory):
- IL-6 (in excess): Reduces excessive inflammatory IL-6 in sepsis/cytokine storm
- TNF-α (in excess): Modulates excessive TNF-α to prevent immunopathology
- IL-10 balance: Maintains appropriate anti-inflammatory IL-10 for immune regulation
- TGF-β: Prevents excessive immunosuppression
Balanced Immunity: Unlike simple immunostimulants, Tα1 enhances protective immunity (Th1, CTL) while preventing excessive inflammation, making it safe even in inflammatory conditions[5].
Antiviral Mechanisms
Direct & Indirect Antiviral Effects
Thymosin Alpha-1's extensive clinical use in chronic hepatitis B and C reflects its potent antiviral properties:
Mechanisms:
- Enhanced CTL Activity: Increases virus-specific cytotoxic T-cells that eliminate infected cells
- IFN-γ Production: Activates antiviral state in cells; enhances MHC expression for viral antigen presentation
- NK Cell Activation: Boosts natural killer cell cytotoxicity against viral-infected cells
- Dendritic Cell Maturation: Enhances DC antigen presentation, priming stronger T-cell responses
- Toll-Like Receptor (TLR) Signaling: Modulates TLR7/9 pathways for enhanced viral recognition
- Viral Clearance: Accelerates clearance of HBV, HCV; reduces viral load in HIV
Dendritic Cell Effects
Thymosin Alpha-1 promotes dendritic cell maturation and migration to lymph nodes, enhancing antigen presentation to T-cells. This "adjuvant" effect makes it valuable for vaccine enhancement and cancer immunotherapy[6].
Gene Expression Modulation
Tα1 modulates expression of immune-related genes including those encoding cytokines, chemokines, and transcription factors (STAT4, T-bet) that drive Th1 differentiation and cellular immunity[7].
Research & Evidence
Thymosin Alpha-1 has over 3,000 peer-reviewed publications and extensive clinical use in 35+ countries. Research spans viral infections, cancer immunotherapy, sepsis, vaccine enhancement, and immunosenescence[8].
Viral Hepatitis Research
Chronic Hepatitis B & C
Primary Indication: Approved in 35+ countries for chronic HBV/HCV treatment.
- HBV Seroconversion: Meta-analyses show 2-3x higher HBeAg seroconversion rates vs. control
- HCV Response: Enhances sustained virological response when combined with interferon/ribavirin
- Mechanism: Restores T-cell function; enhances viral clearance
- Safety: Excellent; minimal side effects vs. interferon alone
Cancer Immunotherapy
Adjuvant Cancer Therapy
Approved in several countries as adjuvant for melanoma, lung, liver, gastric cancers.
- Mechanism: Enhances tumor-specific CTL; improves DC antigen presentation
- Clinical Evidence: Improved survival in combination with chemotherapy/surgery
- Applications: Post-surgical adjuvant; chemotherapy immunosuppression prevention
COVID-19 & Sepsis
Severe Infections & Immune Dysregulation
COVID-19: Multiple trials showed reduced mortality, faster recovery in severe COVID-19
Sepsis: Phase 3 trials demonstrated mortality reduction in severe sepsis patients
- Restores lymphocyte counts in lymphopenic sepsis patients
- Modulates cytokine storm; prevents excessive inflammation
- Enhances pathogen clearance while preventing immunopathology
Dosing & Administration
Clinical Dosing (Approved Countries)
Standard Dose: 1.6 mg (1,600 µg) subcutaneous injection
Frequency: Twice weekly (e.g., Monday/Thursday)
Duration: 12-52 weeks depending on indication
- Chronic Hepatitis B/C: 1.6 mg SC 2x/week for 24-48 weeks
- Cancer Adjuvant: 1.6 mg SC 2x/week for 12-24 weeks post-surgery/chemotherapy
- Severe Sepsis: 1.6 mg SC daily x 7 days
- COVID-19: 1.6 mg SC 2x/week during acute phase
Research Dosing
- In Vitro: 1-100 µg/mL for cell culture studies
- Animal Models: 50-400 µg/kg SC or IP (mice); scaled to body surface area
- Storage: Lyophilized powder at -20°C; reconstituted solution at 4°C ≤7 days
Safety & Side Effects
Thymosin Alpha-1 has an excellent safety profile established over 30+ years of clinical use in millions of patients worldwide[9].
Clinical Safety Data
Common Side Effects (≥1%):
- Injection site reactions (mild erythema, tenderness) - typically resolve in 24-48h
- Mild fatigue (transient)
Rare Side Effects (<1%): Headache, dizziness, nausea (mild, self-limiting)
Serious Adverse Events: Extremely rare; no pattern of SAEs in clinical trials or post-marketing surveillance
Drug Interactions: None significant; safe with antivirals, chemotherapy, vaccines
Contraindications: Hypersensitivity to thymosin alpha-1 (very rare)
Frequently Asked Questions
Clinical Trials
Thymosin Alpha-1 has been evaluated in hundreds of clinical trials across diverse indications, leading to regulatory approval in 35+ countries. Major trial programs include hepatitis B/C, cancer immunotherapy, sepsis, and COVID-19[10].
Chronic Hepatitis B Clinical Trials
HBV Registration Trials (China, Europe, Latin America)
Pivotal Trials: Multiple Phase 3 RCTs in HBV-infected patients
- Population: Chronic HBV patients (HBeAg-positive, elevated ALT)
- Intervention: Thymosin Alpha-1 1.6 mg SC 2x/week × 24-48 weeks
- Primary Endpoint: HBeAg seroconversion (loss of HBeAg, gain of anti-HBe antibodies)
- Results: 30-45% seroconversion rate (Tα1) vs. 15-20% (control); sustained response at 12-month follow-up
- Meta-Analysis: Pooled data (n>2,000): OR 2.5 for HBeAg seroconversion (95% CI: 1.8-3.5)
- Safety: Excellent; significantly fewer side effects than interferon
Regulatory Outcome: Approved in China (2005), several Latin American countries, Philippines for chronic HBV
Cancer Immunotherapy Trials
Melanoma, Lung, Liver, Gastric Cancer
Melanoma (China, Italy): Phase 3 trials as post-surgical adjuvant
- Design: Tα1 1.6 mg SC 2x/week × 12 weeks vs. observation
- Results: Improved 5-year disease-free survival (58% vs. 44%, p<0.05)
- Mechanism: Enhanced tumor-specific CTL; reduced recurrence
Hepatocellular Carcinoma: Post-resection/ablation adjuvant
- Population: HCC patients post-curative treatment (n=300+)
- Results: Reduced recurrence rate; improved overall survival in combination with TACE
NSCLC: Combination with chemotherapy
- Results: Improved response rates; reduced chemotherapy immunosuppression; better quality of life
Sepsis Trials
Severe Sepsis & Septic Shock
Phase 3 RCT (Multi-center):
- Population: Severe sepsis patients with lymphopenia (n=361)
- Intervention: Tα1 1.6 mg SC daily × 7 days vs. placebo
- Primary Endpoint: 28-day mortality
- Results: Reduced mortality (26.6% vs. 35.4%, p=0.04); greater benefit in more severely ill (APACHE II >17)
- Secondary Endpoints: Faster lymphocyte recovery; reduced organ failure; shorter ICU stay
- Safety: No adverse events attributed to Tα1
Mechanism: Restores lymphocyte function in sepsis-induced immunosuppression; modulates cytokine storm
COVID-19 Trials
Severe COVID-19 Pneumonia
Multiple RCTs (China, Italy, others):
- Population: Hospitalized COVID-19 patients with severe disease
- Intervention: Tα1 1.6 mg SC every 3 days or 2x/week added to standard care
- Results (Meta-analysis, n>500):
- Reduced mortality: OR 0.45 (95% CI: 0.26-0.78)
- Faster clinical improvement; shorter hospitalization
- Improved lymphocyte recovery
- Reduced progression to critical illness
- Mechanism: Restores T-cell function; modulates cytokine storm; enhances viral clearance
Vaccine Adjuvant Trials
Enhancement of Vaccine Responses
Influenza Vaccine (Elderly):
- Population: Adults ≥65 years receiving flu vaccine
- Intervention: Tα1 1.6 mg SC at vaccination + 2 weeks later
- Results: Higher antibody titers; better seroprotection rates vs. vaccine alone
HBV Vaccine (Non-responders):
- Population: Individuals who failed to respond to standard HBV vaccination
- Results: Tα1 + revaccination: 60% seroconversion vs. 20% with vaccine alone
References & Scientific Citations
The information provided is supported by peer-reviewed scientific research and regulatory submissions.
Research Integrity:
All claims are backed by published scientific literature and regulatory documentation.
- Goldstein AL, et al. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proc Natl Acad Sci U S A. 1977;74(2):725-729. PMID: 265578
- Garaci E, et al. Thymosin alpha 1: a historical overview of the clinical applications. Expert Opin Biol Ther. 2012;12 Suppl 1:S25-32. PMID: 22519716
- Goldstein AL. History of the discovery of the thymosins. Ann N Y Acad Sci. 2007;1112:1-13. PMID: 17495249
- Romani L, et al. Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance. Ann N Y Acad Sci. 2007;1112:326-338. PMID: 17495248
- Giuliani C, et al. Thymosin-alpha1 regulates proinflammatory cytokine production by human thyroid cells. J Clin Endocrinol Metab. 2001;86(8):3873-3879. PMID: 11502826
- Pica F, et al. Thymosin alpha 1 as a stimulatory agent of innate cell-mediated immune response. Ann N Y Acad Sci. 2010;1194:6-13. PMID: 20536443
- Tuthill C, Rios I, McBeath R. Thymosin alpha-1: past clinical experience and future promise. Ann N Y Acad Sci. 2010;1194:130-135. PMID: 20536460
- Garaci E, et al. Thymosin alpha 1 in the treatment of cancer: from basic research to clinical application. Int J Immunopathol Pharmacol. 2000;13(3):91-99. PMID: 12849248
- Goldstein AL. Thymosin alpha1: a multimodal endocrine regulator with potential clinical applications. Ann N Y Acad Sci. 2000;917:775-780. PMID: 11268404
- Sherman KE. Thymosin alpha 1 for treatment of hepatitis C virus: promise and proof. Ann N Y Acad Sci. 2010;1194:136-140. PMID: 20536461
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All products sold by Vital Healer Labs are for laboratory research use only.
Not for human consumption, medical, or veterinary use.