Research Guides

Thymosin Alpha-1: 5mg vs 10mg Research Guide

By UK Peptide Lab Research Team•19 September 2026•6 min read

Key Takeaways

The 5mg and 10mg vials contain the identical 28-residue, N-terminally acetylated peptide (Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN, 3108.28 g/mol); only the lyophilised mass per vial differs.
Each size is its own batch with its own certificate of analysis; there is deliberately no purity or quality difference between the two.
At an equal fill volume the 5mg vial reaches half the concentration of the 10mg vial, so reconstitution volumes must be scaled rather than carried over.
The sequence has no cysteine or methionine; the C-terminal asparagine deamidates in solution, and the 5mg vial's shorter in-use window helps contain that. Supplied for in-vitro laboratory research only.

Same Molecule, Half the Vial Content

Thymosin alpha-1 is a 28-residue, N-terminally acetylated peptide of 3108.28 g/mol, first isolated from bovine thymus by Goldstein and colleagues (Proc Natl Acad Sci USA, 1977). The 5mg and 10mg vials contain the identical molecule: same sequence, same CAS 62304-98-7, same pharmacology. The only difference is vial content, 5mg of lyophilised powder against 10mg in the same single-vial glass format. There is deliberately no purity or quality difference between the sizes, and each is its own batch with its own certificate of analysis. The full chemistry and literature sit in our Thymosin Alpha-1 research guide; this article covers what the 5mg format changes and what it does not.

What the 5mg Format Suits

The consequences are arithmetic rather than chemical. At an identical fill volume, a 5mg vial reconstitutes to half the concentration of a 10mg vial, so volumes must be scaled rather than carried over. The 5mg format suits designs with a smaller total peptide mass: pilot runs, dose-response screening across modest plate counts, and work where a 10mg vial would leave substantial unused material. The 10mg format wins on batch continuity, one batch and certificate covering twice the work, and on cost per milligram. The 5mg format wins on exposure, since each reconstituted stock is exhausted sooner, and on the lower upfront cost of pilot work. A large design run on 5mg vials spans more batches, so certificate management scales accordingly.

Handling: No Cysteines, No Methionines, One Asparagine

Handling guidance is identical across sizes because the chemistry is. The sequence contains no cysteine, so there are no disulfides, and no methionine, so the oxidation liabilities that dominate handling for many research peptides do not apply. The residue to design around is the C-terminal asparagine, which deamidates in solution at a rate that rises with temperature and pH. Reconstitute with bacteriostatic water injected slowly down the inner glass wall, swirl gently, never shake or vortex, keep the solution at 2-8°C and use within approximately 4 weeks, and aliquot for longer storage. The 5mg vial's shorter working life is itself a stability advantage: the stock is typically finished before deamidation accumulates.

The Honest Boundaries

TA1's pharmaceutical history makes precise framing essential. As Zadaxin (SciClone) it is licensed as a prescription medicine in more than 35 countries for immunomodulatory indications, supported by Chien and colleagues' randomised controlled trial in chronic hepatitis B (Hepatology, 1998), but it has never been licensed in the UK, the EU or the United States. The modern mechanism centres on TLR9-dependent dendritic cell activation (Romani et al., Blood, 2004), the older T-cell literature reviewed by Garaci (Ann N Y Acad Sci, 2007). Nothing here transfers to human use: this material is supplied for in-vitro laboratory research only.

Sourcing in the UK

UK Peptide Lab supplies Thymosin Alpha-1 5mg at £29.99 as lyophilised powder, batch UKPL-9508 at 99.48% purity by HPLC, supplier-tested, with the certificate of analysis published on the product page and independent third-party verification pending. Same-day dispatch on orders before 2pm GMT, free Royal Mail Tracked shipping over £45. For in-vitro laboratory research use only.

Related Products

Thymosin Alpha-1 Thymosin Alpha-1 TB-500 Bacteriostatic Water

Disclaimer: This article is for research and educational purposes only. All information provided is not intended as medical advice. UK Peptide Lab products are not for human consumption and are sold strictly for laboratory research use only.

Frequently Asked Questions

What is the difference between Thymosin Alpha-1 5mg and 10mg?

Only the mass of lyophilised peptide per vial. Both hold the identical 28-residue, N-terminally acetylated thymosin alpha-1 sequence at 3108.28 g/mol (CAS 62304-98-7); the 5mg vial contains half the mass in the same single-vial glass format. There is deliberately no purity or quality difference between the sizes, and each is its own batch with its own published certificate of analysis rather than inheriting the other's figures.

Is the 5mg vial the same quality as the 10mg vial?

Yes, by design. Each vial size is its own batch with its own certificate of analysis, and the 5mg batch UKPL-9508 is verified at 99.48% purity by HPLC on the supplier's analysis, with independent third-party verification pending. The batch number on the certificate matches the batch number printed on the vial you receive.

How do I store and reconstitute the Thymosin Alpha-1 5mg vial?

Store lyophilised vials at -20°C, protected from light and moisture, for up to 24 months. Reconstitute with bacteriostatic water injected slowly down the inner glass wall, swirl gently, never shake or vortex, and hold the solution at 2-8°C, using within approximately 4 weeks. The sequence has no cysteine or methionine, but the C-terminal asparagine deamidates in solution, so keep sessions short and the vial cold. Research use only.

References

[1] Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proc Natl Acad Sci USA (1977). View →
[2] Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling. Blood (2004). View →
[3] Thymosin alpha1: a historical overview. Ann N Y Acad Sci (2007). View →
[4] Efficacy of thymosin alpha1 in patients with chronic hepatitis B: a randomized, controlled trial. Hepatology (1998). View →