Reference
Compare peptides
Two to four compounds, field by field: identity, United States regulatory status, and what kinds of documents are on file. The table records differences. It does not rank them.
No winner, no score, no recommendation. Counts describe how many documents of each kind Therapept has indexed — not how well a compound works, and not how much has been published overall.
Link to this comparison: /compare?peptides=thymosin-alpha-1,tb-500,thymosin-beta-4
| Thymosin alpha-1 | TB-500 | Thymosin beta-4 | |
|---|---|---|---|
| Identity | |||
| Class | Synthetic 28-residue N-acetylated peptide corresponding to the N-terminal fragment of prothymosin alpha | Synthetic acetylated heptapeptide corresponding to the actin-binding region of thymosin beta-4 (residues 17–23) | 43-residue N-terminally acetylated peptide; the parent molecule of the TB-500 fragment |
| Also listed as | Thymalfasin, Tα1, Zadaxin | Thymosin beta-4 fragment (LKKTETQ), Ac-LKKTETQ-OH, TB500 | Timbetasin, Thymosin β4, Tβ4 |
| Molecular formula | C129H215N33O55 | C38H68N10O14 | C212H350N56O78S |
| Molecular weight | 3108.3 g/mol | 889.0 g/mol | 4963 g/mol |
| CAS | 62304-98-7 | 885340-08-9 | 77591-33-4 |
| PubChem CID | 16130571 | 62707662 | 16132341 |
| Sequence length | 28 residues | 7 residues | 43 residues |
| Data caveat | None recorded | TB-500 is commonly described in vendor material as the Ac-SDKP fragment. Full caveat | Much of the wound-healing literature cited in commercial TB-500 material concerns this full-length peptide. Full caveat |
| United States regulatory status | |||
| Status | No FDA-approved product | No FDA-approved product | No FDA-approved product |
| FDA application | None recorded | None recorded | None recorded |
| Compounding | FDA bulk-substance nomination withdrawn; safety concerns remain published. | FDA bulk-substance nomination withdrawn; safety concerns remain published. | No FDA compounding entry recorded |
| WADA | Not named in this record | Named at S2.3 — “Thymosin-β4 and its derivatives e.g. TB-500”. Prohibited at all times; non-Specified. | Named at S2.3 — “Thymosin-β4 and its derivatives e.g. TB-500”, among growth factors and growth factor modulators. Prohibited at all times. |
| Evidence on file | |||
| Records | 3 | 6 | 0 |
| Human-interventional records | 0 | 0 | 0 |
| Human-observational records | 0 | 0 | 0 |
| Animal records | 0 | 1 | 0 |
| In-vitro records | 0 | 0 | 0 |
| Reviews | 1 | 2 | 0 |
| Regulatory documents | 2 | 3 | 0 |
| Earliest indexed | 2016 | 1999 | Not recorded |
| Latest indexed | 2026 | 2026 | Not recorded |
| Records | Open evidence file | Open evidence file | Open evidence file |
Every identity and regulatory value above is taken from the compound’s record, where its sources are listed. Evidence counts are derived from the published evidence file at build time. A missing class means no document of that kind is indexed — not that none exists.