Thymosin Alpha-1
Also known as: Ta1, Thymalfasin, Zadaxin
Overview
Thymosin Alpha-1 (Tα1) is a 28-amino acid peptide naturally secreted by the thymus gland that plays a central role in T-cell maturation, differentiation, and immune function. It was among the first thymic peptides to be structurally characterized and has been developed into the drug thymalfasin (Zadaxin), which has received FDA orphan drug designation and is approved in multiple countries for hepatitis B, hepatitis C, and certain cancers. It was studied extensively during the COVID-19 pandemic for immune modulation.
Mechanism of Action
Thymosin Alpha-1 modulates multiple immune pathways: enhancing T-helper cell (CD4+) and cytotoxic T-cell (CD8+) function; stimulating dendritic cell maturation and activity; augmenting interferon-gamma and interleukin-2 production; enhancing NK cell cytotoxicity; and reducing T-cell exhaustion. In cancer, it attenuates chemotherapy-induced immune damage. In viral infections, it restores lymphocyte counts and prevents lymphopenia. It also reduces chemotherapy toxicity and acts as a vaccine adjuvant by improving immune response magnitude.
Potential Benefits
- FDA orphan drug designation for malignant melanoma, hepatitis B, DiGeorge anomaly
- Approved in multiple countries for hepatitis B and C treatment
- Reduces chemotherapy-associated immune suppression
- Restores T-cell counts in COVID-19 lymphopenia patients
- Vaccine adjuvant activity enhancing antibody responses
- Reduces mortality in sepsis patients (shown in meta-analysis)
- Anti-tumor immune activation in multiple cancer types
- Modulates dendritic cells to enhance antifungal and antiviral immunity
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Typical Range | 1.6-3.2 mg twice weekly |
| Beginner | 0.8-1.6 mg twice weekly |
| Intermediate | 1.6 mg twice weekly (standard clinical dose) |
| Advanced | 3.2-6.4 mg twice weekly (intensive immune protocols) |
| Cycle Duration | 4-6 weeks intensive; longer for chronic conditions |
| Cycle Off | 2-4 weeks; maintenance dosing 1x/week may be used long-term |
Zadaxin (pharmaceutical TA1) is dosed at 1.6 mg subcutaneously twice weekly. For immune enhancement in healthy individuals, shorter 4-6 week cycles are typical. Approved in 35+ countries for hepatitis B/C and as cancer adjuvant.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection High — systemic immune modulation
Standard method (used in Zadaxin pharmaceutical). Typical dose 1.6 mg, 2x per week. Clinically validated route with decades of data.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Thymosin Alpha-1:
Immune Modulation Stack
Innate + adaptive immune support. Thymosin Alpha-1 enhances T cell and NK cell function while LL-37 provides direct antimicrobial defense.
Cancer Support Stack
Immune and metabolic support (adjunctive only). Thymosin Alpha-1 enhances immune surveillance, MOTS-C supports mitochondrial function and metabolic health.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Typical Vial Size | 1.6mg (Zadaxin standard), 10mg (research) |
|---|---|
| BAC Water | 1ml per 1.6mg vial |
| Storage | Refrigerate at 2-8°C after reconstitution |
| Shelf Life | Zadaxin: use immediately after reconstitution; research vials: 28 days refrigerated |
Need exact syringe measurements?
Amino Acid Sequence
Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH
Side Effects & Safety
- Generally well-tolerated with excellent safety profile
- Mild injection site reactions
- Occasional fatigue
- Rare allergic reactions
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Drug Interactions
- Immunosuppressant Therapy:
FDA Safety Information
FDA Category 2 concerns: significant immunogenicity risk, inadequate safety data.
Pharmacokinetics
| Half-Life | ~2 hours |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside Thymosin Alpha-1 for potential complementary or synergistic effects:
Learn More
References & Further Reading
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