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Inclusion of a compound does not constitute endorsement. Information sourced from published research and regulatory filings.

Thymosin Alpha-1

Cat 2 → Pending Cat 1

Growth & Recovery · Research peptide (Zadaxin by SciClone Pharmaceuticals in approved markets)

Naturally occurring thymic peptide researched for immune modulation, T-cell enhancement, and dendritic cell activation. Approved as Zadaxin in over 30 countries but not FDA-approved in the US.

About

Mechanism
Naturally occurring thymic peptide. Enhances T-cell maturation and function, activates dendritic cells, augments antibody responses. Modulates cytokine production.
Half-Life
Approximately 2 hours
Route
subcutaneous
Frequency
2x/week

Clinical Dosing

1.6-3.2 mg2x/week

Not FDA-approved in the US. Approved as Zadaxin in over 30 countries for hepatitis B/C and as immune adjuvant. Currently FDA Category 2 (restricted) in US.

Dosing based on small human studies or early-phase trials. Not established by Phase 3 evidence.

Regulatory Status

FDA Category
Research peptide in US (approved in 30+ countries as Zadaxin)
Reclassification
pending
Date Restricted
2023-09-29
Announced Return
2026-02-27

Status based on publicly available FDA communications. Verify at FDA.gov for authoritative guidance.

View full regulatory timeline →

Titration Protocols

Zadaxin Label Protocol

Source: Garaci et al., International Immunopharmacology, 2012

DoseDurationDraw (3 mg vial in 2mL)Notes
1.6 mgMaintenance1.07 mL (107 units)Standard dose 2x/week

Available Vial Sizes

3 mg

3 mg vial

5 mg

5 mg vial

Citations

  1. [1]Thymosin Alpha-1: From Bench to Bedside. International Immunopharmacology, 12(4), 555-562. Link(Reviewed: 2026-02-27)