Immune & Thymic

Thymosin Alpha-1

Also known as Ta1 · Tα1 · Thymalfasin · Zadaxin

Clinically studiedSubcutaneous injectionIntramuscular injectionApproved in 35+ countries (e.g., as Zadaxin/thymalfasin) for hepatitis B and immune indications; NOT FDA-approved in the US. Holds US Orphan Drug designation for some indications but no US marketing approval.

Thymosin Alpha-1 is a peptide originally isolated from the thymus gland that helps regulate T-cell maturation, dendritic cell function, and the balance of pro- and anti-inflammatory signaling, largely through Toll-like receptor pathways. As the synthetic drug thymalfasin (Zadaxin), it has been used internationally for chronic hepatitis B and as an immune adjuvant. It is among the more extensively studied peptides in this category, with controlled trials spanning antiviral, oncology-adjunct, and immune-support settings.

Studied / used for

Used in protocols for immune modulation and T-cell support
Studied for chronic hepatitis B as an antiviral adjunct
Studied as a vaccine response adjuvant
Studied as an adjunct in certain oncology and sepsis settings

Commonly reported side effects

Injection-site pain, burning, or itching
Fever
Flu-like symptoms
Nausea

Clinically studied. Supported by human clinical trials. This reflects the strength of the research base, not effectiveness or a recommendation.

Not medical advice.

This is an educational reference. Peptalk does not recommend, prescribe, endorse, or rate any compound, and provides no dosing information. Do not start, stop, or change any peptide, hormone, supplement, or therapy based on this page. All clinical decisions must be made with your licensed healthcare provider.

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