Thymosin Alpha-1 — Wolverine Health

How it works

A 28-amino-acid peptide originally isolated from calf thymic tissue. It modulates both innate and adaptive immunity — upregulating dendritic cell maturation, increasing T-cell activity, and enhancing natural killer cell function. Approved in over 35 countries under the brand name Zadaxin for viral hepatitis and as an adjuvant in immunocompromised patients. Not FDA-approved. It occupies an unusual regulatory position: extensive international clinical history, no approved US indication, compoundable as a 503A bulk substance.

FDA status: Not FDA-approved in the US. Approved in 35+ countries for viral hepatitis (Zadaxin). Compoundable by 503A pharmacies in the US as it has no active FDA NDA.
WADA status: Permitted in sport
Route: subcutaneous injection

Key studies

Thymosin alpha 1: biological activities and clinical applications — Garaci et al.

Thymosin alpha-1 is a 28-amino-acid thymic peptide that enhances T-lymphocyte function, natural killer cell activity, and cytokine production in immunodeficiency and chronic infection models.

Wolverine Health is building physician-supervised peptide protocols. Get early access.

Join the waitlist

Research on Thymosin Alpha-1

The thymus: the vanishing organ behind your ageing immune system

WADA

The thymus trained every immune cell you own, then started shrinking in your teens. Its slow fade is a big reason immunity gets weaker with age — and the reason a family of thymus-signal peptides is worth understanding. Here is the biology, in plain language.

Thymosin Alpha-1: the ageing immune system's missing signal

WADA

Thymosin Alpha-1 is a signal your thymus makes to direct your immune system — and makes less as you age. It carries the deepest human trial record on this menu, including a null 2025 sepsis trial in the BMJ. Here's what it could do for your immune system, and exactly how far the proof goes.

Thymosin Alpha-1: the immune peptide with a real drug record

WADA

Thymosin Alpha-1 is the rare peptide that is already an approved drug in dozens of countries — a signal your thymus makes to run your immune system, and makes less of as you age. Here is what it could do for you, the range of what it has been used for, and where the US regulation actually stands.