If a supplied lot fails agreed specifications, we’ll replace it at no cost or refund its purchase price in full.
Quality test failed? Free replacement or full refund.
Off-spec? Free replacement or full refund.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epithalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
28-amino-acid thymic immune-modulation peptide
Supply and ordering
Ask sales about Thymosin Alpha 1 availability, order quantities, packaging, and batch documentation. Include other catalog items in the same inquiry if you are planning a combined or recurring order.
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 to a ≥99.0% HPLC purity specification. 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, every released lot comes with its batch COA, including the HPLC chromatogram and mass spec; water content, counter-ion, endotoxin (LAL) and microbial limits are available on request and listed on the COA when tested. 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
Also available as a nasal spray (US stock)
Besides lyophilized vials, Thymosin Alpha 1 is stocked in the US as a ready-to-use nasal spray.
Documentation available on request
Each picture is a low-resolution preview of a report's first page, with batch and report numbers covered. For the full, clear report, ask our sales team, naming the product and strength.
Batch COAThymosin Alpha 1 5 mg
HPLC purity · MS identity
Batch COA
Full, clear copy from sales
Batch COAThymosin Alpha 1 10 mg
HPLC purity · MS identity
Batch COA
Full, clear copy from sales
Third-party reportThymosin Alpha-1 5 mg
HPLC purity · MS identity
Third-party laboratory, Tianjin, China
Full, clear copy from sales
Third-party reportThymosin Alpha-1 10 mg
HPLC purity · MS identity
Third-party laboratory, Tianjin, China
Full, clear copy from sales
Independent test fails? Full refund. How it works
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
Frequently asked questions
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.
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.
Review the matching batch COA for the storage, retest, identity, and other results actually recorded for the lot. If a buyer's written procedure requires LC-MS/MS, endotoxin, or another additional test, agree the laboratory, method, specification, sample, timing, report, and buyer-funded cost with sales before quotation unless different written terms are accepted.
Yes. Thymosin Alpha 1 is also stocked as a ready-to-use nasal spray (10 mg) in 10 mL or 20 mL bottles, from 10 bottles of each. These orders ship from our US stock; ask our sales team for details and a quote.
Send any vial from your order to an independent laboratory of your choice. If the report shows the product does not meet the specification on its COA — purity below the stated minimum, or an identity that does not match — share the report with our sales team and we refund that product in full.
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