This is an identity reference for thymosin alpha-1. It describes what the name denotes, how it differs from compounds with similar names, and its analytical characteristics. It makes no claim about what the compound does and gives no preparation or handling guidance.
What the name refers to
Thymosin alpha-1 is a 28-residue peptide, N-terminally acetylated, originally isolated from thymus tissue and now produced synthetically. It is a linear sequence of standard L-amino acids with no disulfide bridges, and the N-terminal acetyl group is part of the specification rather than an optional modification.
The naming confusion worth resolving
Thymosin alpha-1 and thymosin beta-4 are unrelated molecules that share a historical naming convention because both were isolated from the same tissue extract. They differ in length, sequence and structure. The short fragment commonly sold as TB-500 derives from thymosin beta-4, not from thymosin alpha-1, and the two should never be treated as variants of one another in a record.
Ordering errors in this area come from abbreviation. “Thymosin” alone is not an identifier. Record the full compound name and the sequence.
Analytical characteristics
Chain length. At 28 residues this is among the longer compounds in the catalogue. Peak width increases with size, and wide-pore stationary phases generally give better resolution for peptides in this range than the pore sizes used for short sequences.
N-terminal acetylation. Acetylation adds 42 Da relative to the free-amine form and removes one positive charge, which changes both mass and retention. Non-acetylated material is a distinct impurity, distinguishable by mass spectrometry, and a supplier’s specification should state that the N-terminus is acetylated.
Acidic character. The sequence is notably rich in acidic residues, which makes the molecule unusually polar for its length. It retains less strongly than chain length alone would predict, and a method developed for a typical hydrophobic peptide of similar size may not be appropriate.
Aromatic content. Aromatic residues are sparse in this sequence, so 280 nm is a poor basis for either purity assessment or quantification. Analysis at 214 nm is the appropriate method.
Deletion sequences. In a 28-residue synthesis, the cumulative probability of at least one coupling failure is meaningful even at high per-step efficiency. Deletion sequences are the expected impurity class, they differ from the target by a single residue, and they elute close to the main peak. A shallow gradient earns its time on a compound of this length.
Confirming identity independently
Verify the full 28-residue sequence and the N-terminal acetylation against public chemical databases rather than relying on the name. Our product pages carry compound identity links that run those searches.
What we publish
Thymosin alpha-1 sits in our antimicrobial and cytokine-pathway peptides category, grouped by the pathway it is studied against rather than by any intended outcome. Its product page carries an independent reverse-phase HPLC analysis, net peptide content, counter-ion form and vial size. Vials carry no batch or lot numbers and are matched to their published test by crimp and cap colour.
Research use only. All products supplied by Battle Born Peptides are laboratory reference materials for in-vitro research and analytical use by qualified professionals. They are not drugs, foods, dietary supplements, cosmetics or medical devices; they are not approved by the FDA or any other regulator for use in humans or animals; and they are not intended to diagnose, treat, cure, mitigate or prevent any disease, or to affect the structure or any function of the body of humans or animals. Nothing in this article is preparation, handling or dosing guidance. See our full research-use terms.