Thymosin Alpha 1 (Tα1), also known as Zadaxin or Thymalfasin, is a naturally occurring 28-amino acid peptide hormone produced by the thymus gland. It plays a key role in modulating the immune system, particularly by enhancing T-cell function and promoting immune balance. Synthetic versions are used therapeutically.

Key Biological Functions

• Immune Modulation: Stimulates differentiation and maturation of T-cells (including CD4+ helper T-cells, CD8+ cytotoxic T-cells, and natural killer cells). It boosts cytokine production (e.g., IL-2, IFN-γ) without causing excessive inflammation.
• Antiviral Effects: Enhances antiviral immunity by improving dendritic cell function and antigen presentation.
• Anti-Cancer Potential: Supports anti-tumor immunity by activating immune cells against cancer.
• Evidence: Derived from thymosin fraction 5 (isolated in the 1960s by Allan Goldstein). Human studies show it restores thymic function in immunocompromised states (e.g., HIV, chemotherapy).

Medical Uses and Approvals

Dosage: Typically 1.6 mg subcutaneous injection, 2x/week for 6 months (varies by indication). Half-life ~2 hours.

Mechanism of Action

Tα1 binds Toll-like receptors (TLR-2/9) on antigen-presenting cells, upregulating MHC class I/II and costimulatory molecules. It doesn’t directly kill pathogens but amplifies adaptive immunity.

Molecular Structure:

(SEQ ID: 28 aa, MW ~3108 Da)

Side Effects and Safety

• Common: Mild injection-site reactions (redness, pain).
• Rare: Fatigue, nausea (<5% incidence).
• Contraindications: Hypersensitivity; caution in autoimmunity (theoretical risk of overactivation).
• Safety Data: Well-tolerated in 20+ years of use; no genotoxicity or teratogenicity in preclinical studies (FDA IND status).

Availability and Legality

• Prescription: Not FDA-approved in the US (available via compounding pharmacies or research peptides).
• Research: Widely studied (PubMed: 1,500+ papers). Ongoing trials for Lyme disease, TB, and post-viral fatigue.
• Peptide Therapy Context: Popular in functional medicine for “immune reboot” (e.g., 5-10 mg/week cycles), often stacked with BPC-157 or TB-500.

Recent Research Highlights

• Long COVID: Italian trial (Infectious Disease Reports 2023) showed symptom resolution in 80% vs. 40% placebo.
• Cancer Immunotherapy: Synergy with checkpoint inhibitors (Cancer Immunol Res 2022).
• Aging: Restores thymic output in elderly (Aging Cell 2020).

For sourcing or personal use, consult a physician—it’s not a DIY supplement. Sources: ClinicalTrials.gov, PubMed, SciDirect. If you have a specific question (e.g., dosing protocols, studies), let me know!