Thymosin Alpha-1 (CAS 62304-98-7), also known as Thymalfasin, is a synthetic 28-amino acid peptide with the molecular formula C129H215N33O55 and a molecular weight of 3108.34 g/mol. Defined by the amino acid sequence 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-OH, Thymalfasin features a characteristic N-terminal acetylation and is the most extensively characterised individual peptide within the thymosin family. Produced via solid-phase peptide synthesis, Thymalfasin signals through Toll-like receptors (TLRs) and is associated with T-cell maturation and innate immune signalling pathways in preclinical immunology research.

Thymosin Alpha-1 has been extensively investigated as one of the most widely studied thymic peptides in preclinical and translational immunology. Published in vitro studies in dendritic cell preparations have examined Thymalfasin’s interaction with Toll-like receptors (specifically TLR2 and TLR9) and downstream MyD88-dependent signalling cascades, documenting dendritic cell activation and Th1 immune polarisation as primary signalling outputs of Thymosin Alpha-1-mediated TLR engagement and characterising IL-12 production and IFN-γ secretion as downstream readouts of receptor-mediated dendritic cell maturation under controlled conditions [1]. In vivo mouse studies have investigated Thymalfasin/Thymosin α1 in immunological challenge models, including murine cytomegalovirus infection and cyclophosphamide-conditioned tumour models. These studies documented antiviral immune activation through TLR9/MyD88/IRF7-dependent pathways and IFN-α/IFN-γ responses, as well as dependence on CD4/CD8 T-cell and NK-cell compartments in cyclophosphamide-treated mice, consistent with Thymalfasin as an immunomodulatory agent acting across innate and adaptive immune responses under conditions of immune challenge [2,3], making Thymosin Alpha-1 a key reference compound in thymic peptide research examining TLR-mediated innate immune signalling and T-cell maturation in preclinical immunology models.

Thymosin Alpha-1 is manufactured in a cGMP compliant laboratory to a guaranteed purity of 98% or above. Every batch is independently tested using HPLC and MS-UPLC analysis before dispatch. Vials are vacuum sealed and stored in a temperature controlled, monitored cold storage system. Certificates of Analysis are available on request.

Sold strictly for in vitro research purposes only. Not for human consumption. Intended for use by qualified researchers in laboratory settings only.

Editorial Team

Dr. Martina Rossi, PhD

Scientific Contributor and Reviewer

Reviewed and approved 14 June 2026

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