Comparison · 2026-09-24
Scientific lead: Alice Kay, Ph.D.
Thymosin Alpha-1 vs TB-500: Research Comparison
Research-use notice: This page records catalogue differences only: sequences, receptor classes, fill sizes, and Certificate of Analysis rows. It is not a protocol. It is not medical or veterinary advice, and it does not rank materials for personal use. BlueNex Labs materials are research use only. Research-use-only labelling is not a Health Canada authorization and it does not create a Drug Identification Number.
Thymosin is a family name with at least two catalogue members that do not match. Thymosin alpha-1 is a defined 28-residue thymic peptide. TB-500 is named here as a fragment from the beta family. Buying one because a form said "thymosin" is a documentation error before it is anything else. For the glossary entry, see thymosin. For the alpha-1 guide, see thymosin alpha-1. For the fragment guide, see What is TB-500?.
Alpha family versus beta fragment
Thymosin alpha-1 is described in the thymosin literature as an N-acetylated 28-residue peptide. The sequence used in that literature is 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. Low, Goldstein, and colleagues reported the sequence analysis of thymosin alpha-1 in the Journal of Biological Chemistry in 1979. Twenty-eight residues, an acetylated N terminus, and a thymic origin are the structural marks. The shop listing calls the same object a 28-residue thymic peptide for T-cell signalling models. That is a laboratory frame. It is not a personal-use claim, and this page does not add one.
Thymosin beta-4 is a different polypeptide, 43 residues, discussed as an actin-binding protein. TB-500 on this site is not that full chain and it is not thymosin alpha-1. The catalogue calls it a synthetic fragment modelled on a region of thymosin beta-4. Fragment papers discuss Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln, residues 17-23, as the actin-binding motif. Seven residues versus 28 is enough to separate the masses. The N-terminal acetylated tetrapeptide of thymosin beta-4, sometimes called Ac-SDKP in other papers, is a third fragment and is not a catalogue SKU. Do not collapse three thymosin strings into the TB-500 vial.
Signalling language stays with the paper
Alpha-1 papers are usually about lymphocyte signalling in a stated model. Beta-4 fragment papers are usually about actin and cell migration in a stated model. Those are different experimental objects. A result in one system does not rename the other peptide, and it does not authorize a substitution when the purchasing line used only the family word. BPC-157, a gastric pentadecapeptide, is a third object again. Its comparison with TB-500 is BPC-157 vs TB-500, including the blend vials that contain both of those sequences and do not contain thymosin alpha-1.
| Record | Thymosin alpha-1 | TB-500 |
|---|---|---|
| Sequence or length | 28 residues, N-acetylated thymic peptide | Named as a thymosin beta-4 fragment; fragment literature discusses a 7-residue actin-binding motif |
| Molecular class | Thymosin alpha family | Thymosin beta-4 fragment, not the alpha family |
| Receptor or target class | Discussed in T-cell and lymphocyte signalling models | Discussed in actin-binding and cell-migration models |
| Catalogue size | 10 mg | 10 mg |
| COA | No library row on the September 20, 2026 review. | View certificate. Blend PDFs do not cover this vial. |
Equal milligrams, separate certificates
Both live listings are 10 mg. The equal fill is not an identity. Thymosin alpha-1 still has no certificate anchor. TB-500 10 mg has its purity report on the TB-500 10 mg certificate. The published 5 mg/5 mg BPC-157 / TB-500 report names that blend. It does not name thymosin alpha-1, and it does not name the TB-500-only vial. How to read a peptide COA describes what to check: sample name, method, area percent, and mass.
A 28-residue mass and a short-fragment mass will disagree if the wrong sequence was assumed. That disagreement is useful. Record it against the slug you opened, which is thymosin alpha-1 or TB-500, not against the word thymosin. The cellular hub is where these cards sit beside matrix peptides. The hub is not a shared lot.
Thymosin alpha-1 still has no published lot. Write the sequence family, the 10 mg fill, the shop slug, and the sentence "certificate not on the September 20, 2026 library review" for that vial only. That sentence is a record. It is not a defect to be papered over with a blend PDF. For TB-500 10 mg, record the report on the TB-500 10 mg certificate. A bookmarked absence is evidence about that review date, not about every vial that arrives afterward.
Domestic fulfilment
Orders ship inside Canada after Interac e-Transfer, on Canada Post Xpresspost. Read Canada laboratory procurement for the desk facts. This comparison is not a city page. Research use only. Not for human or veterinary use.
Frequently asked questions
- Is TB-500 a vial of thymosin alpha-1?
- No. Thymosin alpha-1 is a 28-residue thymic peptide. TB-500 is named on this catalogue as a thymosin beta-4 fragment. The family word thymosin does not make the sequences the same.
- Do these 10 mg listings share a certificate?
- No. Thymosin alpha-1 has no library row, and TB-500 10 mg has its own report on the TB-500 10 mg certificate. The BPC-157 / TB-500 5 mg/5 mg blend report does not document thymosin alpha-1, and it does not document TB-500 alone.
- What does research use only mean here?
- Each solid is for laboratory work. This comparison does not provide personal-use steps, and research-use-only labelling is not a Health Canada authorization.
Research use only. BlueNex Labs does not provide medical or veterinary advice. Confirm your institution’s policies before purchase. How a comparison or class note is checked sits on documentation standards. The biochemist of record is Alice Kay, Ph.D.