Thymosin Alpha-1 · DOSSIER

Thymosin Alpha-1

Tα1 · Thymalfasin · Peptide · 28 AS
LEGAL DE · NOT APPROVEDEVIDENCE · EARLY CLINICAL STUDIES3 STUDIES
FIG.01 — SIGNAL CHAIN
Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN · ~3108.3 Da
02

Mechanism of action

What Thymosin Alpha-1 does in the body — step by step.

01

Thymosin alpha-1 (Tα1) is a 28-amino-acid peptide originally isolated as fraction 5 from the thymus.

02

It is a natural cleavage product of prothymosin alpha and is produced mainly in thymic epithelial cells.

03

Tα1 modulates T-cell maturation and function: it promotes the Th1 response, increases the activity of natural killer cells (NK cells) and stimulates the production of IL-2, interferon-gamma and interferon-alpha.

03

Research status

How far along is the evidence?

PRECLINICALEARLY CLINICAL STUDIESCLINICALLY ESTABLISHED
Among peptides not approved in the EU, thymosin alpha-1 has a comparatively strong clinical evidence base.
Among peptides not approved in the EU, thymosin alpha-1 has a comparatively strong clinical evidence base.
In China and several other countries, Zadaxin (thymalfasin) is approved for the treatment of chronic hepatitis B and C and as an adjuvant in malignant disease.
Several randomised controlled studies have investigated Tα1 in hepatitis B (reduced viral load, improved HBeAg seroconversion) and sepsis-associated immune deficiencies.
During the COVID-19 pandemic, thymosin alpha-1 was used in China as a supportive treatment; retrospective analyses showed reduced mortality in severely ill patients in some studies, though methodological limitations exist.
04

Known risks

Without human data, safety statements are limited. What is known:

01
Generally well tolerated in clinical studies — no serious safety signal known
02
Local injection-site reactions (pain, redness) the most commonly described side effect
03
Theoretical risk of immune stimulation in pre-existing autoimmune conditions
04
Long-term data for continuous use outside clinical studies are lacking
05
Quality control not guaranteed from unapproved sources
05

Cited studies

Chronological — links lead to the source.

2010
Thymalfasin for the treatment of hepatitis B: a meta-analysis
PubMed 20091901 →
2016
Thymosin alpha 1: past, present, and future
PubMed 27184285 →
2022
Effect of thymosin alpha 1 on COVID-19 patients with moderate illness: a randomized clinical trial
PubMed 35790070 →
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Frequently asked questions

What is Thymosin Alpha-1?+

Thymosin alpha-1 (Tα1) is a 28-amino-acid peptide originally isolated as fraction 5 from the thymus.

What type of peptide is Thymosin Alpha-1?+

Thymosin Alpha-1 belongs to the Thymic peptide class.

What is Thymosin Alpha-1 used for?+

In research, Thymosin Alpha-1 has primarily been investigated in the context of: Immunomodulation, Anti-aging. These are research findings (evidence: early clinical studies), not proven benefits in humans and not a usage recommendation.

Is Thymosin Alpha-1 legal in Germany?+

Thymosin Alpha-1 is not approved as a medicine in Germany. Obtaining it outside clinical studies is legally problematic.

Is Thymosin Alpha-1 FDA-approved / legal in the US?+

No. Thymosin Alpha-1 is not FDA-approved as a drug in the US; it is mostly sold as a research chemical and not for human consumption.

Is Thymosin Alpha-1 legal in Canada?+

No. Thymosin Alpha-1 is not authorized by Health Canada and not intended for human consumption.

Where can I buy Thymosin Alpha-1?+

Peptica sells nothing and names no sources. Thymosin Alpha-1 is "not approved" in Germany; obtaining unapproved substances outside clinical studies is illegal and carries quality and safety risks.

What is the dosage of Thymosin Alpha-1?+

Peptica publishes no dosing. There are no approved dosing guidelines for Thymosin Alpha-1; figures circulating online stem from animal studies or anecdote, not from validated human protocols. This is not medical advice.

Is Thymosin Alpha-1 banned in sport (WADA)?+

Thymosin Alpha-1 is currently not on the WADA Prohibited List.

What are the known risks of Thymosin Alpha-1?+

Documented risks include: Generally well tolerated in clinical studies — no serious safety signal known; Local injection-site reactions (pain, redness) the most commonly described side effect. This is not a complete safety assessment and not medical advice — see the risks section for the full list.

How well researched is Thymosin Alpha-1?+

The evidence is classified as “early clinical studies”. 3 studies are cited on this page.

What is the molecular weight of Thymosin Alpha-1?+

Thymosin Alpha-1 has a molar mass of about 3108.3 Da, with a plasma half-life of ~2 hours.

Which peptides are related to Thymosin Alpha-1?+

Closely related entries: Epithalon, LL-37. A direct side-by-side comparison is available via the compare function.

07

Dossier

Legal · Structure · Sources.

LEGAL STATUS BY REGION
Germanynot approved

Thymalfasin (Zadaxin) is not approved as a medicine in the EU, Germany, Austria or Switzerland. It is approved in China, Italy and about 35 other countries for hepatitis indications. Not on the WADA list. Importing it without a medical prescription and approval is legally problematic in Germany (AMG).

Legal status varies by country and can change. This is not legal advice.

STRUCTURE & MOLECULE
H₂NAc-SDAAVDTSSEITTKDLKEKKEVVEEAENCOOH
28
AMINO ACIDS
~3108.3
MOL. WEIGHT (Da)
~2 hours
HALF-LIFE
SOURCES & EXTERNAL DATABASES

Methodology: Peptica compiles publicly available studies and regulatory information and assigns each statement an evidence level. Not medical advice. No warranty.

RELATED PEPTIDES & FURTHER READING
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Community notes

Note: These posts are user opinions and not medical advice. Posts containing dosages, therapeutic claims or purchase recommendations are removed. All entries are manually reviewed before publication.
This page is intended solely for factual, scientifically oriented information. No medical advice · no dosage or usage recommendations · no claims of efficacy · no substitute for medical consultation. Peptica sells no substances. Partner links are marked as advertising; Peptica may earn a commission. © 2026 Peptica · Issue 01