Thymosin Alpha-1

Compoundable (Rx)

Immune Peptides · Immune Modulation

Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus gland that plays a critical role in immune system regulation.

What is Thymosin Alpha-1?

Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus gland that plays a critical role in immune system regulation. It is approved in over 35 countries for hepatitis B/C treatment and used as an immune adjuvant. Interest surged post-COVID for its immune-modulating properties.

Also known as: Tα1, Ta1

How Does Thymosin Alpha-1 Work?

Enhances T-cell maturation and function, promotes dendritic cell differentiation, modulates cytokine production (IL-2, IFN-α, IFN-γ), and activates natural killer cells. Restores immune balance rather than simply boosting immunity, making it useful in both immunodeficiency and autoimmune conditions.

What is Thymosin Alpha-1 Used For?

Immune modulation
Hepatitis B/C
Cancer adjuvant therapy
Vaccine enhancement
Infection resistance

Potential Side Effects

Injection site irritation
Mild flu-like symptoms (rare)
Rash (very rare)

Contraindications

Organ transplant recipients
Immunosuppressive therapy

FDA Legal Status

United States — FDA

Compoundable (Rx)

Category 1 (restored 2026)

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Frequently Asked Questions

What is Thymosin Alpha-1 used for?

Thymosin Alpha-1 is used to modulate and restore immune function. It is approved in 35+ countries for hepatitis B/C treatment, used as a cancer immunotherapy adjuvant, and increasingly used for general immune optimization, chronic infections, and as a vaccine response enhancer.

Is Thymosin Alpha-1 safe for autoimmune conditions?

Unlike simple immune boosters, Thymosin Alpha-1 modulates rather than stimulates. Some practitioners use it cautiously in autoimmune conditions, as it can help restore immune balance. However, this should only be done under medical supervision.

Quick Facts

Legal Status (USA): Compoundable (Rx)
FDA Category: Category 1 (restored 2026)
Evidence Rating: AStrong Evidence (Multiple RCTs)
Class / Subclass: Immune Peptides / Immune Modulation
Administration: subcutaneous
Typical Dosage: 1.6mg twice weekly
Half-Life: ~2 hours
Brand Names: Zadaxin
Year Discovered: 1977
Approval Year: 1999

Sources

PubMed 17078754

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

PubMed PMID 17078754 — peer-reviewed primary literature on Thymosin Alpha-1.
FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.