All information below describes the compound's chemical identity, laboratory handling, and the published research literature. It describes molecular targets and results in laboratory and animal models only — not effects in humans — and is not evidence of any human benefit.
What Is Thymosin Alpha-1?
Thymosin Alpha-1 (also written Thymosin α1, and known by the international nonproprietary name thymalfasin) is a 28-amino-acid peptide with an N-terminally acetylated serine (sequence SDAAVDTSSEITTKDLKEKKEVVEEAEN). It corresponds to a fragment of the larger precursor protein prothymosin alpha and was first isolated from thymic tissue (thymosin fraction 5) by Goldstein and colleagues in the 1970s. The reference material supplied here is produced by chemical synthesis as a characterized analogue of the naturally occurring sequence.
A thymalfasin drug product is marketed under the trade name Zadaxin and is registered in a number of jurisdictions outside the United States. The material supplied by Explicit Research is research-grade and is not that approved drug product; it is provided as a reference compound for in vitro and animal research use only. The sections below summarize its chemical identity, laboratory handling, the molecular targets and model systems examined in the published literature, and the primary references — without describing outcomes, efficacy, or effects in humans.
Research Targets & Pathways
Published preclinical literature has examined Thymosin Alpha-1 in relation to several molecular systems. These are pathway associations reported in laboratory and animal models; refer to the cited studies for methods and findings.
- Toll-like receptor signaling — examined in relation to TLR2 and TLR9 engagement and the downstream MyD88 adaptor in immune-cell model systems.
- Dendritic-cell maturation pathways — studied in relation to dendritic-cell surface-marker and cytokine-signaling assays.
- NF-κB transcriptional axis — reported downstream of Toll-like receptor pathway activation in cellular models.
- Thymocyte / T-cell differentiation — investigated in thymocyte maturation and T-cell subset differentiation assay systems.
- Interferon and cytokine induction — examined in relation to type-I/type-II interferon and interleukin signaling pathways in peripheral blood mononuclear cell (PBMC) systems.
Model Systems Studied
Thymosin Alpha-1 has been used as a test compound across a range of published preclinical and experimental model systems, primarily in vitro immune-cell assays and disease-oriented models. Refer to the cited literature for study designs, endpoints, and findings.
- In vitro immune cell — PBMC cultures, dendritic-cell cultures, lymphocyte-proliferation, and T-cell differentiation assay systems.
- Viral infection models — cellular models of hepatitis B virus (HBV), hepatitis C virus (HCV), and SARS-CoV-2.
- Oncology / tumor immunology — tumor-immunology assay systems and checkpoint-pathway model systems.
- Systemic inflammation — sepsis and severe-acute-inflammation model systems.
- Hepatic — liver-injury and fibrosis-marker model systems.
Note: much of the published clinical literature originates from jurisdictions where a thymalfasin drug product holds regulatory approval; those data describe the approved product and are not extrapolable to research-grade material used in laboratory contexts.
Stability & Handling
Thymosin Alpha-1 is supplied as a lyophilized powder. As a fully synthetic peptide it is handled under the same general conventions as other research peptides: stored desiccated and cold in its lyophilized state, reconstituted in an aqueous solvent immediately before use, and aliquoted to limit freeze-thaw cycling. The compound is described in the literature as water-soluble; solvent choice, working concentration, and storage duration should be confirmed against the lot-specific Certificate of Analysis for each experimental system.
Molecular & Technical Profile
C129H215N33O55 | MW ~3108.3 g/mol (approx.) | CAS 62304-98-7 | Sequence: Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN (28 residues)
Storage, Reconstitution & Working Concentrations
Storage, reconstitution, and working-concentration values are general laboratory guidance for in vitro and animal research; always confirm against the lot-specific Certificate of Analysis. The molecular weight is given as an approximate value; confirm exact mass against the lot-specific COA.
Current Research Status
As of the time of this writing, Thymosin Alpha-1 has not been approved by the U.S. Food and Drug Administration (FDA) for any human use. A thymalfasin drug product (Zadaxin) is registered in a number of countries outside the United States, but that regulatory status applies to the approved drug product and not to research-grade reference material. Much of the published human clinical literature reflects trials conducted in those jurisdictions and is geographically concentrated; independent replication and standardized outcome reporting remain limited. Ongoing preclinical research continues to characterize the compound's mechanistic profile and molecular-target associations in laboratory and animal model systems.
Research FAQ
Is Thymosin Alpha-1 approved for human use?
The material supplied here is research-grade and is not the approved drug product. A thymalfasin drug (marketed as Zadaxin) is registered in a number of countries outside the United States, but Thymosin Alpha-1 is not FDA-approved for any human use in the United States and is supplied for laboratory research use only — not for human consumption.
What is Thymosin Alpha-1's molecular formula and sequence?
A synthetic 28-residue peptide with an N-terminally acetylated serine, sequence Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN — molecular formula C129H215N33O55, MW approximately 3108.3 g/mol, CAS 62304-98-7.
How is Thymosin Alpha-1 stored and reconstituted?
Store lyophilized at −20°C, desiccated and protected from light. Reconstitute in sterile water or sterile PBS (pH 7.4); store the reconstituted solution at 2–8°C for up to ~28 days and avoid repeated freeze–thaw.
What molecular targets has Thymosin Alpha-1 been studied for?
Preclinical work has characterized associations with Toll-like receptor signaling (TLR2, TLR9) and the MyD88 adaptor, dendritic-cell maturation pathways, the NF-κB axis, and thymocyte / T-cell differentiation, across in vitro immune-cell, viral-infection, oncology, and systemic-inflammation model systems. Note the geographic-concentration caveat for the clinical literature noted above.
Selected References
- Goldstein AL, Badamchian M. (2004). Thymosins: chemistry and biological properties in health and disease. Expert Opinion on Biological Therapy, 4(4):559–73.
- Romani L, et al. (2007). Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance. Annals of the New York Academy of Sciences, 1112:326–38.
- Pica F, et al. (2007). Effect of thymosin alpha1 on dendritic cell function and Toll-like receptor signaling. International Immunopharmacology, 7(13):1730–7.
- Garaci E, et al. (2010). Thymosin alpha1: from bench to bedside. Annals of the New York Academy of Sciences, 1194:1–13.
- Andreone P, et al. (2004). Thymalfasin (thymosin alpha1) in chronic hepatitis B: pharmacology and clinical review. Expert Review of Anti-infective Therapy, 2(5):701–11.
- Zhang Y, et al. (2023). Molecular mechanisms of thymosin alpha1 in viral infectious diseases. Molecules, 28(8):3539.