Thymosin Alpha-1

Immunomodulatory 28-residue peptide

Identifier graph

Cross-references to canonical chemistry knowledge graphs. Each binding is the same identity used in PubMed-indexed literature.

CAS Registry Number
62304-98-7 · CAS Common Chemistry
InChIKey
NZVYCXVTEHPMHE-ZSUJOUNUSA-N
PubChem CID
CID 16130571
Wikidata
Q20817234
ChEMBL
CHEMBL412531
Molecular formula
C129H215N33O55
Molecular weight
3108.30 g/mol
IUPAC name
(4S)-4-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S,3R)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-acetamido-3-hydroxypropanoyl]amino]-3-carboxypropanoyl]amino]propanoyl]amino]propanoyl]amino]-3-methylbutanoyl]amino]-3-carboxypropanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-3-hydroxypropanoyl]amino]-4-carboxybutanoyl]amino]-3-methylpentanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxybutanoyl]amino]-6-aminohexanoyl]amino]-3-carboxypropanoyl]amino]-4-methylpentanoyl]amino]-6-aminohexanoyl]amino]-4-carboxybutanoyl]amino]-6-aminohexanoyl]amino]-6-aminohexanoyl]amino]-4-carboxybutanoyl]amino]-3-methylbutanoyl]amino]-3-methylbutanoyl]amino]-4-carboxybutanoyl]amino]-4-carboxybutanoyl]amino]propanoyl]amino]-5-[[(1S)-3-amino-1-carboxy-3-oxopropyl]amino]-5-oxopentanoic acid

What is Thymosin Alpha-1?

Thymosin Alpha-1 (Tα1, also called Thymalfasin and marketed as Zadaxin) is a 28-residue acetylated peptide originally identified in calf thymus extract by Goldstein and colleagues in the 1970s. The peptide is enzymatically derived from a longer precursor (Prothymosin-α) and is one of the most clinically-developed immunomodulatory peptides — Tα1 is licensed in over 30 countries for adjunctive use in viral hepatitis and immunocompromised states.

CAS 62304-98-7, molecular formula C₁₂₉H₂₁₅N₃₃O₅₅, molecular weight 3108.30 g/mol. Wikidata QID Q20817234, PubChem CID 16130571, ChEMBL ID CHEMBL412531.

Mechanism of action

Thymosin Alpha-1 is a Toll-like receptor (TLR) agonist — principally TLR9 and TLR2 — and modulates dendritic-cell maturation, T-cell differentiation toward Th1 responses, and natural-killer-cell activity. The peptide does not act on a single high-affinity receptor in the way of small-molecule drugs; rather, it shapes innate-immunity signalling broadly, producing a more competent adaptive-immunity response in immunocompromised states.

Research context

One of the most-published immunomodulatory peptides. Investigated in clinical and preclinical studies of viral infection (hepatitis B and C, cytomegalovirus, HIV-related immunocompromise), cancer immunotherapy adjuvant studies, and immunocompromised-host vaccine response.

Analytical specifications

Every batch of Thymosin Alpha-1 supplied by NMChem is characterised by reversed-phase HPLC for purity determination and by mass spectrometry for identity confirmation. Certificate of Analysis (COA) documents are issued per batch and made available on request.

Identity is confirmed by electrospray-ionisation mass spectrometry (ESI-MS); the observed mass falls within ±2 Da of the theoretical monoisotopic mass calculated from the residue sequence. Purity is determined by reversed-phase HPLC on a C18 column with a trifluoroacetic-acid-modified water/acetonitrile gradient and reported as the area-under-curve percentage of the main peak at 214 nm. NMChem specification is ≥99% main peak. Material ships as lyophilised powder and must be reconstituted in sterile water or bacteriostatic water immediately before use.

Browse the COA database

UK regulatory status

Supplied as a research-grade reference standard for laboratory use only. Not a licensed medicinal product in the United Kingdom and not approved by the MHRA for human or veterinary administration. Sale is restricted to researchers, institutions and laboratory professionals; the compound must be retained within research premises. End-user compliance with the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 (where applicable) and local institutional biosafety policy is the responsibility of the buyer.

Research literature

Selected peer-reviewed publications from PubMed referencing this compound.

  1. Thymosin α-1 Reverses M2 Polarization of Tumor-Associated Macrophages during Efferocytosis. Wei YT et al. · Cancer research · 2022
    PubMed PMID 35364609
  2. Thymosin alpha-1. Ancell CD et al. · American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists · 2001
    PubMed PMID 11381492
  3. Aging and Thymosin Alpha-1. Simonova MA et al. · International journal of molecular sciences · 2025
    PubMed PMID 41373628

Related compounds

Other research compounds in adjacent mechanism classes or commonly used alongside Thymosin Alpha-1.

  • TB-500
    Synthetic Thymosin Beta-4 fragment · 17-residue peptide
  • Thymalin
    Thymus peptide extract · Khavinson preparation

Frequently asked questions about Thymosin Alpha-1

What's the difference between Thymosin Alpha-1 and Thymosin Beta-4?
Despite the similar names, Thymosin Alpha-1 and Thymosin Beta-4 (TB-500's parent protein) are structurally unrelated and act through completely different mechanisms. Thymosin Alpha-1 is an immunomodulatory peptide acting via TLR signalling. Thymosin Beta-4 is an actin-binding protein involved in tissue repair. They share only the genus name 'thymosin' as a historical artefact of their joint discovery in thymus extracts.
Is Thymosin Alpha-1 licensed in the UK?
Thymosin Alpha-1 (as Zadaxin) is licensed in over 30 countries for adjunctive use in viral hepatitis and immunocompromised conditions. It is not currently MHRA-licensed in the UK. NMChem supplies it as a research-grade reference standard for laboratory characterisation only.

Get research-grade Thymosin Alpha-1 from NMChem

UK supplier · HPLC and MS verified · Per-batch Certificate of Analysis · Tracked Royal Mail dispatch.

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