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Thymosin Alpha-1 vial

Thymosin Alpha-1

Also searched as: thymosin alpha 1, ta1 peptide

$80 In stock

Ships from

For research use only. Not for human or veterinary use.

Ships from the USA or Canada. Shipping details

Thymosin Alpha-1 (drug name thymalfasin) is a synthetic peptide of 28 amino acids with an acetylated N-terminus,14 sold here as one vial of freeze-dried powder for laboratory research. PubChem classes it as an immunologic adjuvant, a substance that stimulates or modulates immune responses.1 FDA has approved no drug that contains it.5

Specifications

Sequence (one-letter code)Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN-OH (acetylated N-terminus)1
Sequence (three-letter code)Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH1
Length28 amino acids14
Molecular formulaC129H215N33O552
Molar mass3108.3 g/mol2
CAS number62304-98-7, used for both the free base and the acetate salt (PubChem also lists 69521-94-4)35
PubChem CID161305712
FormFreeze-dried (lyophilized) powder
Vial contentsOne vial; the strength per vial and the salt form (free base or acetate) are not yet listed, so read the vial label before any concentration math
Ships fromUSA, Canada
StorageFDA reports that Ta1 free base should be stored desiccated below -18 °C, and that the acetate salt is kept in a sealed container at 2 to 8 °C or in a freezer, where it is reported stable below -20 °C.5

Supplies for Thymosin Alpha-1

Bulk and wholesale orders

Labs planning a longer series of experiments can ask for Thymosin Alpha-1 in larger quantities through a wholesale account. Quantity terms are confirmed on application.

Wholesale detailsApply for a wholesale account

Questions about Thymosin Alpha-1

About Thymosin Alpha-1

Thymosin Alpha-1 (Ta1) is a peptide of 28 amino acids first isolated from calf thymus in 1977, as one of several peptides in thymosin fraction 5, a crude thymus extract.64 The body makes its own Ta1 by cutting it from a larger protein, prothymosin alpha.7 In lab and animal studies it acts on immune cells.4 A brand version, Zadaxin, is approved in Italy and some other countries, mostly for hepatitis B or as a vaccine adjuvant.4

This page lists Thymosin Alpha-1 for sale as a research vial, with the Thymosin Alpha-1 price and stock for each origin in the selector above. Read What is Thymosin Alpha-1? for the full evidence before you buy Thymosin Alpha-1 for a study.

Research highlights

  • Pharmacokinetics, 9 healthy volunteers (1999): after an injection under the skin, blood levels peaked in 1 to 2 hours, with an elimination half-life under 3 hours.13
  • Immune effects, lab and animal studies: FDA summarizes reports that Ta1 can raise natural killer cell activity and activate dendritic cells, effects proposed to run at least partly through Toll-like receptor 9.45
  • Melanoma in mice: every dose tested, from 0.02 to 6 mg/kg, reduced tumor size by 45 to 50%, so higher doses added no effect.4
  • Chronic hepatitis B, double-blind phase 3 trial in 97 patients (1999): complete response was 14% on Ta1 and 4% on placebo (P = 0.084, not significant).11
  • Sepsis, TESTS phase 3 trial in 1,106 adults (2025): 28-day mortality was 23.4% on Ta1 and 24.1% on placebo (hazard ratio 0.99, P = 0.93), and no secondary or safety outcome differed significantly.12
  • FDA review (2024): FDA found a lack of evidence of effectiveness for all 12 uses it evaluated, including infections, cancers and vaccine response.5

Regulatory status

FDA has approved no drug product that contains Ta1.5 In December 2024, FDA's Pharmacy Compounding Advisory Committee voted 17 to 4 against adding the free base, and 17 to 4 against the acetate salt, to the 503A bulks list used for pharmacy compounding.8 FDA also says compounded Ta1 may pose a significant risk of immunogenicity (immune reactions) for certain routes of administration.9 USADA's advisory on the 2027 WADA Prohibited List, which takes effect on January 1, 2027, does not name Ta1, but it warns that a peptide not named on the List may still be prohibited.10 Every vial is labeled: For research use only. Not for human or veterinary use.

Handling and storage

FDA reports a water solubility of up to 2 mg/mL for Ta1 free base and up to 1 mg/mL for the acetate salt, which it says is difficult to reconstitute in water.5 The highest strength FDA found in clinical studies was 2 mg/mL, and it said a more concentrated solution could aggregate.5 So each mg needs at least 0.5 mL of water (free base) or 1 mL (acetate); confirm the strength on the vial label first. Once dissolved, the free base was reported stable for 2 to 7 days at 4 °C, or below -18 °C for later use.5 The lab steps are in How to reconstitute a peptide vial, and the reconstitution calculator does the concentration math.

Frequently asked questions

Where can I buy thymosin alpha 1?

This page sells Thymosin Alpha-1 as a freeze-dried vial for laboratory research, with stock and the current price for each shipping origin in the selector. It is not for use in people. It is also not Zadaxin, the brand approved abroad: FDA calls Zadaxin a finished drug product that cannot be used interchangeably with Ta1 as a substance.4

Where does Thymosin Alpha-1 ship from?

Orders ship from the USA and Canada to addresses across the United States. Thymosin Alpha-1 is listed with two shipping origins, and the selector above shows the stock status of each one before the vial goes in your cart. Processing, delivery and other shipping details are on the shipping page.

What strength is the Thymosin Alpha-1 vial?

The listing offers one standard vial, and the strength per vial is not yet stated here, so read the vial label before any concentration math. Strength matters for mixing, because FDA reports a water solubility of only up to 2 mg/mL for the free base and up to 1 mg/mL for the acetate salt.5

How should Thymosin Alpha-1 be stored when it arrives?

A freezer suits both dry forms FDA describes: the free base is stored desiccated below -18 °C, and the acetate salt in a sealed container at 2 to 8 °C or a freezer.5 That matters while the listing does not state the salt form. FDA adds that formulation, processing and environmental conditions may cause aggregation and degradation.5 See How to store peptides.

Is there a certificate of analysis for Thymosin Alpha-1?

Certificates and lab documents, where available, are listed on the lab results page. Check which tests a Ta1 certificate covers. FDA's 2024 review found both the free base and the acetate not well characterized, lacking key data on impurities, aggregates and bacterial endotoxin,5 so a purity figure alone leaves those questions open.

What supplies are used with a Thymosin Alpha-1 vial?

The supplies listed for this vial are bacteriostatic water as a diluent, a 3 mL Luer-Lok syringe, an 18G 1-inch needle, insulin syringes and alcohol swabs. Which of them a lab needs depends on its method and the vial strength. These are lab handling supplies, not directions for use in people.

Written by D2C Peptides Editorial Team.

Pending qualified review.

Updated .

Sources

  1. PubChem Compound CID 16130571 (Thymalfasin): full record (PUG View), Biologic Line Notation and Pharmacology sections. PubChem, National Library of Medicine (NIH), 2026.
  2. PubChem Compound CID 16130571 (Thymalfasin): computed properties (PUG REST). PubChem, National Library of Medicine (NIH), 2026.
  3. PubChem Compound CID 16130571 (Thymalfasin): CAS section (PUG View). PubChem, National Library of Medicine (NIH), 2026.
  4. FDA Evaluation of Thymosin Alpha-1 (Ta1) Related Bulk Drug Substances (Ta1 (free base) and Ta1 acetate), FDA Briefing Document, Pharmacy Compounding Advisory Committee, December 4, 2024 (memo dated 11/15/2024). U.S. Food and Drug Administration, 2024.
  5. Thymosin Alpha-1 (Ta1) Related Bulk Drug Substances (FDA presentation slides, Pharmacy Compounding Advisory Committee Meeting, December 4, 2024). U.S. Food and Drug Administration, 2024.
  6. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide (Goldstein AL et al.; PMID 265536, PMCID PMC392366). Proceedings of the National Academy of Sciences of the USA (abstract via PubMed, NCBI E-utilities), 1977.
  7. Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance (Romani L et al.; PMID 17495242). Annals of the New York Academy of Sciences (abstract via PubMed, NCBI E-utilities), 2007.
  8. Final Summary Minutes of the Pharmacy Compounding Advisory Committee Meeting, December 4, 2024. U.S. Food and Drug Administration, 2025.
  9. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Thymosin-alpha 1 (Ta1) row, 'Bulk drug substances nominated but withdrawn' table). U.S. Food and Drug Administration, 2026.
  10. Athlete Advisory: What's New on the 2027 WADA Prohibited List? U.S. Anti-Doping Agency (USADA), 2026.
  11. Thymosin alpha1 treatment of chronic hepatitis B: results of a phase III multicentre, randomized, double-blind and placebo-controlled study (Mutchnick MG et al.; PMID 10607256). Journal of Viral Hepatitis (abstract via PubMed, NCBI E-utilities), 1999.
  12. TESTS trial: thymosin α1 in adults with sepsis, multicentre, double blinded, randomised, placebo controlled, phase 3 (Wu J et al.; PMID 39814420, PMCID PMC11780596, DOI 10.1136/bmj-2024-082583). BMJ (abstract via PubMed, NCBI E-utilities), 2025.
  13. Pharmacokinetics of thymosin alpha1 after subcutaneous injection of three different formulations in healthy volunteers (Rost KL et al.; PMID 10027483). International Journal of Clinical Pharmacology and Therapeutics (abstract via PubMed, NCBI E-utilities), 1999.
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