Thymosin Alpha-1 (Thymalfasin)

PeptideXpo buyer fit

Overview

Thymosin Alpha-1 (also known as Thymalfasin, brand name Zadaxin) is a 28-amino-acid N-terminally acetylated peptide originally isolated from bovine thymus and now produced synthetically. It is approved as a prescription biological in over 35 jurisdictions (including China, Italy, India, and several Southeast Asian markets) for indications including chronic hepatitis B, chronic hepatitis C as combination therapy, and as a vaccine adjuvant. The molecule's mechanism centers on enhancement of T-cell maturation and function through TLR-9 dependent dendritic-cell activation, plus broader effects on NK-cell and macrophage activity, the basis for both the antiviral and immune-restoration research interest. PeptideXpo supplies Thymosin Alpha-1 as a lyophilized powder at ≥99.0% HPLC purity. The 28-residue sequence is well within reliable SPPS range, and the N-terminal acetylation is confirmed by mass spec at +42 Da relative to the unmodified peptide. Because Thymosin Alpha-1 is an approved biological in multiple jurisdictions and the supply chain serves both compounding pharmacy and research-lab buyers, the documentation packet emphasizes batch-specific COA depth: HPLC chromatogram, mass spec, water content, counter-ion, and on-request endotoxin (LAL) and microbial limits. Standard 5 mg and 10 mg fills cover most workflows.

Who buys this, and why

Buyers in this category are research labs studying immune-modulation, cytokine signaling, and antimicrobial activity. The defining QC requirement is bacterial-endotoxin control: many of the downstream assays (NF-κB reporters, macrophage activation panels, neutrophil-priming readouts) are themselves activated by endotoxin contamination, so a clean LAL on the specific batch is a precondition rather than a nice-to-have. LL-37 and related cationic antimicrobial peptides additionally benefit from low-bind plasticware during dilution.

Primary buyer fit: 503A / 503B compounding pharmacies and academic and contract research laboratories.

Specifications

CAS

62304-98-7

Sequence

SDAAVDTSSEITTKDLKEKKEVVEEAEN

Appearance

White to off-white lyophilized powder

Purity (HPLC)

≥ 99.0%

Strength

2 mg – 10 mg

Packaging

10 vials/box · base pack (multiples of 10)

Half-life

≈ 3 hours

MOQ

On request

Lead time

10–18 days

Storage

2–8°C, protect from light

Documentation available on request

• Certificate of Analysis (COA)
• HPLC Chromatogram
• Mass-spec identity (ESI-MS)
• Bacterial endotoxin (LAL, USP <85>)
• Microbial limits (USP <61>/<62>)
• Bioburden screening
• Sequence verification (LC-MS/MS)
• SDS / MSDS

Regulatory note

Approved as a prescription biological in over 35 jurisdictions including China, Italy, India, and several APAC markets (brand name Zadaxin or generic equivalents). Sold only to qualified buyers with appropriate licensing in their jurisdiction; not approved in the US or EU at the time of writing.

Selected literature

1. Goldstein AL, Low TL, McAdoo M, McClure J, Thurman GB, Rossio J, Lai CY, Chang D, Wang SS, Harvey C, Ramel AH, Meienhofer J. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proc Natl Acad Sci U S A. 1977;74(2):725-729.
2. Romani L, Bistoni F, Montagnoli C, Gaziano R, Bozza S, Bonifazi P, Zelante T, Moretti S, Rasi G, Garaci E, Puccetti P. Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance. Ann N Y Acad Sci. 2007;1112:326-338.
3. Wu J, Zhou L, Liu J, Ma G, Kou Q, He Z, Chen J, Ou-Yang B, Chen M, Li Y, Wu X, Gu B, Chen L, Zou Z, Qiang X, Chen Y, Lin A, Zhang G, Guan X; Chinese Severe Sepsis Cooperation Group. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Crit Care. 2013;17(1):R8.
4. Gu B, Zhou Y, Nie Y, Wang L, Liang L, Liao Z, Wen J, Guan X, Chen M, Wu J, Pei F. Efficacy of thymosin α1 for sepsis: a systematic review and meta-analysis of randomized controlled trials. Front Cell Infect Microbiol. 2025;15:1673959.
5. Liu F, Wang HM, Wang T, Zhang YM, Zhu X. The efficacy of thymosin α1 as immunomodulatory treatment for sepsis: a systematic review of randomized controlled trials. BMC Infect Dis. 2016;16:488.
6. Liu Y, Pang Y, Hu Z, Wu M, Wang C, Feng Z, Mao C, Tan Y, Liu Y, Chen L, Li M, Wang G, Yuan Z, Diao B, Wu Y, Chen Y. Thymosin alpha 1 (Tα1) reduces the mortality of severe COVID-19 by restoration of lymphocytopenia and reversion of exhausted T cells. Clin Infect Dis. 2020;71(16):2150-2157.

Frequently asked questions