Thymosin Alpha-1 (Thymalfasin)
28-amino-acid thymic immune-modulation peptide
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. Lyochem 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 signalling, and antimicrobial activity. The defining QC requirement is bacterial-endotoxin control: many downstream assays (NF-κB reporters, macrophage-activation panels, neutrophil-priming readouts) are themselves activated by endotoxin contamination, so a clean LAL on the specific lot 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: research laboratories that have validated this peptide into their workflow and academic and contract research laboratories.
Specifications
- CAS
- 62304-98-7
- Sequence
- SDAAVDTSSEITTKDLKEKKEVVEEAEN
- Appearance
- White lyophilized powder
- Purity (HPLC)
- ≥ 99.0%
- Common vial sizes
- 5 mg, 10 mg
- MOQ
- On request
- Lead time
- 10–18 days
- Storage
- -20°C, protect from light
Documentation available on request
- Lot-specific Certificate of Analysis (CoA)
- RP-HPLC chromatogram with peak integration
- ESI-MS identity confirmation (±0.5 Da)
- Sequence verification by LC-MS/MS
- Water content by Karl Fischer
- SDS / MSDS
- Bacterial endotoxin (LAL, USP <85>) — recommended for in vivo work
- Microbial limits (USP <61>/<62>) on request
- Low-bind plasticware notes for cationic AMPs
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.
Frequently asked questions
What's the difference between Thymosin Alpha-1, Thymalin, and Thymulin?▾
These three are commonly confused but are distinct molecules. Thymosin Alpha-1 (also called Thymalfasin) is a defined 28-amino-acid synthetic peptide with a single CAS (62304-98-7), the molecule with the largest body of clinical data and the approved drug status in multiple jurisdictions. Thymulin is a 9-amino-acid zinc-binding peptide (CAS 63958-90-7), a different molecule with limited approved status. Thymalin is generally not a single defined peptide but a thymic-extract complex with batch-to-batch compositional variation. Buyers should be explicit about which they want at quote stage, they are not interchangeable.
Why is Thymosin Alpha-1 approved as a finished drug in some markets but not the US?▾
Thymosin Alpha-1 has approved status in over 35 jurisdictions including China, Italy, India, Singapore, the Philippines, and several other markets, primarily for chronic hepatitis B and as a chemotherapy / vaccine adjuvant. The molecule was developed and clinically advanced primarily outside the US, and the FDA-approval pathway was not pursued historically due to commercial considerations rather than safety or efficacy concerns. Buyers in countries where Thymosin Alpha-1 is an approved medication can reference the local registry; buyers elsewhere are supplied on a research-use-only basis.
What stability and analytical considerations apply specifically to Thymosin Alpha-1?▾
Lyophilized Thymosin Alpha-1 is stable for the standard 24-month re-test window at -20 °C. The N-terminal acetylation is the diagnostic identity check by mass spec (theoretical MW 3108 Da; the +42 Da relative to the unacetylated form is the confirmation). Sequence verification by LC-MS/MS is recommended at first-time supplier qualification because the 28-residue sequence has multiple Asp and Glu residues whose deamidation byproducts elute close to the target peak on RP-HPLC. For compounding pharmacy use the bacterial endotoxin (LAL) test is the standard add-on; for research workflows the LAL is optional but recommended for any in vivo or immune-cell readout where endotoxin would confound interpretation.
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