Thymosin Alpha-1 (Tα1)

Introduction

Thymosin alpha-1 (Tα1, thymalfasin) is a 28-amino-acid acetylated peptide originally isolated from the thymus, now produced synthetically. Marketed as Zadaxin and approved in dozens of countries (not the United States) for indications including chronic hepatitis B, chronic hepatitis C, and as an immune adjunct in vaccination and oncology supportive care.

Mechanism of Action

Modulates innate and adaptive immunity through multiple mechanisms: maturation of T-lymphocytes, polarization of dendritic cells toward a productive antigen-presenting phenotype, modulation of TLR signaling (notably TLR2 and TLR9), and a general dampening of pathologic inflammation while preserving protective immune function.

Approved and Investigated Indications

Approved abroad: chronic hepatitis B, chronic hepatitis C, immune adjunct for vaccination in elderly or immunocompromised populations, supportive care in selected oncology contexts. Investigational/off-label: chronic Lyme, post-viral fatigue, severe respiratory viral illness, immune support in cancer therapy.

Reconstitution

Zadaxin is supplied as a 1.6 mg lyophilized vial with 1 mL of supplied diluent (sterile water for injection). Reconstitute per labeling — final concentration 1.6 mg/mL, entire vial is the dose.

Compounded research-grade: 5 mg vial add 2.5 mL of bacteriostatic water, swirl gently. Final concentration 2 mg/mL — each 0.8 mL delivers 1.6 mg.

Dosing Protocol (research literature)

Zadaxin labeled regimen: 1.6 mg subcutaneously twice weekly (e.g., Monday and Thursday) for hepatitis B/C protocols, typically 6 months continuous. Immune-adjunct protocols in oncology and chronic infection use similar twice-weekly 1.6 mg SC regimens for 3–6 months with reassessment.

Administration

Subcutaneous into the abdomen, thigh, or upper arm, rotating sites. Schedule the two weekly doses 3–4 days apart.

Storage & Handling

Lyophilized Zadaxin: refrigerate (2–8°C). Reconstituted Zadaxin: per labeling, use immediately. Compounded research-grade with bacteriostatic water: refrigerate; stable approximately 28 days. Protect from light.

Side Effects

One of the better-tolerated immunomodulators in clinical use — adverse-effect profile is predominantly mild injection-site reactions. Rare hypersensitivity. Theoretical concerns relate to autoimmune disease activation given immune-modulatory mechanism.

Contraindications

Active transplant immunosuppression without specialist input, pregnancy, lactation.

Monitoring

Baseline CBC with differential, comprehensive metabolic panel, and indication-appropriate viral or immunologic markers (e.g., HCV viral load, lymphocyte subsets). Re-measure at 8 and 24 weeks.

Disclaimer

This article is for informational and research-reference purposes only. Nothing in this document constitutes medical advice, a prescription, or a recommendation from a physician. The reconstitution, dosing, and protocol information above reflects ranges commonly cited in published research and clinician-directed protocols — it is provided as reference material only, not as instructions, an endorsement of off-label use, or a substitute for individualized medical evaluation.

Customers should do their own research and consult their own physician before considering any peptide protocol. Whether a given compound is appropriate for an individual — and at what dose, for what duration, and alongside what monitoring — is a decision that only a licensed clinician with knowledge of that individual's medical history, current medications, and conditions can make.

The platform and the author make no claim that any compound described here is safe, effective, or appropriate for any particular person or purpose, and accept no responsibility for outcomes arising from self-directed use of the information.