Thymosin Alpha-1

What is Thymosin Alpha-1?

The 5mg vial is the lower-mass presentation of thymosin alpha-1 (TA1, INN thymalfasin), the 28-residue, N-terminally acetylated peptide of sequence Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN, molecular weight 3108.28 g/mol, CAS 62304-98-7. The compound is identical to the one in the 10mg vial, same sequence, same receptor pharmacology, and the full chemistry (first isolation from bovine thymus and characterisation by Goldstein and colleagues, Proc Natl Acad Sci USA, 1977), the Zadaxin licensing history and the toll-like receptor mechanism reported by Romani and colleagues (Blood, 2004) are documented on the main Thymosin Alpha-1 page and are not repeated here. This page covers what is specific to the 5mg format: half the lyophilised mass of the 10mg vial in the same single-vial glass format, which means half the concentration at a given fill volume, a smaller total peptide mass for pilot and screening-stage designs, and a shorter in-use window per vial that naturally limits cumulative exposure of the deamidation-prone C-terminal asparagine. Supplied as lyophilised powder for in-vitro laboratory research use only.

Thymosin Alpha-1 5mg vs 10mg

The two vials contain the same molecule, so this is a handling and logistics comparison rather than a chemical one, and there is deliberately no purity or quality difference between the sizes. Each vial size is its own batch with its own certificate of analysis: the 5mg batch UKPL-9508 carries its own published certificate rather than inheriting the 10mg batch's figures. The 5mg vial is the lower-mass format for protocols that call for a smaller total peptide mass, 5mg lyophilised in the same single-vial glass format as the 10mg vial. At an identical fill volume the reconstituted stock reaches half the concentration of the 10mg vial, so fill volumes must be scaled rather than carried over from larger-vial work. The trade-offs run in both directions. In the 10mg vial's favour: batch continuity, since one batch under one certificate covers double the work, and a lower cost per milligram, since vial, stopper, lyophilisation and assay costs are incurred per vial rather than per milligram. In the 5mg vial's favour: a lower upfront cost for pilot and screening work, a shorter in-use window per vial that limits the cumulative exposure any single reconstituted stock accumulates, and less unused material left over when a design is revised or abandoned. The counterpoint is that a large design run on 5mg vials spans more batches than the same design on 10mg vials, so inter-batch variance and certificate management scale accordingly. Which size to choose is a logistics decision, not a scientific one.

Thymosin Alpha-1 Research Applications

The applications are those documented for the 10mg vial, since the compound is the same: T-cell maturation and function models, dendritic cell and natural killer cell activity assays, cytokine regulation studies and toll-like receptor signalling work following Romani and colleagues (Blood, 2004), plus recent oncology literature examining TA1 alongside immune checkpoint inhibitors (Wang et al., Cancer Manag Res, 2025). Vial content affects study logistics rather than endpoint selection. A 5mg vial suits pilot runs, dose-response screening across a modest plate count, and designs where the total peptide mass required is small enough that a 10mg vial would leave substantial unused material. The honest boundaries are unchanged from the main page: the licensed indications are prescription medicine uses in specific jurisdictions, much of the older immunology literature is small and heterogeneous, and the recent checkpoint-inhibitor combination data are largely retrospective. Material supplied here is for in-vitro laboratory research only.

Reconstitution Guide

Allow the vial to reach room temperature, then sterilise the rubber stopper of both the peptide vial and the bacteriostatic water vial with an alcohol swab. Draw the bacteriostatic water into a sterile syringe and inject it slowly down the inner glass wall of the peptide vial, never directly onto the lyophilised powder. Swirl gently in a slow circular motion until fully dissolved; the solution should be clear and colourless. Do not shake or vortex. The sequence contains no cysteine and no methionine, so no disulfide or oxidation-specific handling is required, but the C-terminal asparagine is deamidation-prone: reconstitute promptly, avoid introducing excess air, and refrigerate immediately after labelling the vial with the reconstitution date. One point is specific to the 5mg vial: set the fill volume from your target concentration, since 5mg reaches half the concentration of 10mg at identical volume. We specify no fill volume, as that is a protocol decision, and provide no dosing information.

See our full peptide reconstitution guide and reconstitution calculator for step-by-step protocol.

Storage Instructions

Lyophilised vials should be stored at -20°C, protected from light and moisture, and remain stable for up to 24 months. Once reconstituted with bacteriostatic water, store the solution at 2-8°C (standard refrigerator) and use within approximately 4 weeks. For longer storage, prepare single-use aliquots at -20°C and avoid repeated freeze-thaw cycles. The degradation route to design against is deamidation of the C-terminal asparagine, which is accelerated in solution at higher pH and temperature. The 5mg format's practical advantage is that a single reconstituted stock is typically consumed within fewer working sessions, so cumulative room-temperature exposure is naturally limited; the matching discipline is to keep each session short, keep the vial cold between draws, and never store the solution in contact with alkaline solutions. Handle under sterile laboratory conditions throughout.

Frequently Asked Questions

Research References

• Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide (Goldstein et al., Proc Natl Acad Sci USA, 1977)
• Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling (Romani et al., Blood, 2004)
• Thymosin alpha1: a historical overview (Garaci, Ann N Y Acad Sci, 2007)

Related Research Compounds

• → Thymosin Alpha-1 10mg (main product page)
• → TB-500
• → Bacteriostatic Water 10ml