What Is Thymosin Alpha-1?

Also known as: Tα1, Zadaxin

Thymosin Alpha-1 is a 28-amino-acid peptide originally isolated from the thymus gland, the immune system's training center. Unlike most compounds here, it is an approved pharmaceutical in over 35 countries under the name Zadaxin, used for hepatitis B/C and as an immune adjuvant.

It works as an immune modulator rather than stimulant — enhancing T-cell maturation and dendritic-cell function. It drew mainstream attention during COVID-19, when it was trialed for immune support in serious infection.

What is Thymosin Alpha-1 studied for?

Side effects & safety

The best-characterized safety profile on this site thanks to real clinical use: generally well tolerated, with injection-site reactions the main complaint. Autoimmune conditions warrant medical guidance, since immune amplification cuts both ways.

Legal & approval status

Approved abroad (Zadaxin); in the US it is not FDA-approved and moved into restricted compounding territory in 2023 — now largely research-vendor supplied.

Typical dosing at a glance

Commonly reported protocols use 450 mcg1.6 mg, 2x weekly, via subcutaneous injection. For the mixing math — how much bacteriostatic water, exact syringe units, doses per vial — see the Thymosin Alpha-1 reconstitution calculator →

Related peptides

Educational overview based on published research and commonly reported community protocols — not medical advice, and not an endorsement of any compound. Consult a licensed healthcare provider.