BPC-157 vs TB-500
Structural and analytical comparison · research use only
BPC-157 and TB-500 are the two most frequently co-studied peptides in tissue-model literature, and they are routinely confused for one another. They are not structurally related. This page compares only what can be stated objectively: identity, molecular profile, and supplied format.
| Property | BPC-157 | TB-500 |
|---|---|---|
| Classification | Synthetic pentadecapeptide | Synthetic fragment of thymosin beta-4 |
| Chain length | 15 amino acids | Short actin-binding fragment of a 43-residue parent protein |
| CAS number | 137525-51-0 | 77591-33-4 |
| Molecular formula | C62H98N16O22 | C212H350N56O78S |
| Molecular weight | 1419.53 g/mol | 4963.44 g/mol |
| Sequence origin | Partial sequence identified in gastric juice | Region of the thymosin beta-4 protein |
| Supplied format | Lyophilized powder, sealed vial | Lyophilized powder, sealed vial |
| Purity standard | ≥99.2% (HPLC) | ≥99.2% (HPLC) |
What they have in common
Both are supplied as lyophilized (freeze-dried) white powders in sealed vials, both are reconstituted the same way in the laboratory, and both are released only against an independent U.S. laboratory report confirming identity by mass spectrometry and purity by reverse-phase HPLC. Both appear in the preclinical tissue-model literature, which is why they are so often discussed together.
Where they differ
The difference that matters analytically is size and origin. BPC-157 is a short, fully synthetic 15-residue chain with a molecular weight near 1,420 g/mol. TB-500 is a fragment of a much larger naturally occurring protein and is roughly 3.5× heavier at about 4,963 g/mol. That mass difference is what separates them on a chromatogram and in mass-spectrometric identity confirmation — they are not interchangeable reference materials, and a COA for one tells you nothing about the other.
Handling
Identical in practice: store the sealed lyophilized vial at −20 °C protected from light and moisture, reconstitute immediately before study, and avoid repeated freeze-thaw of reconstituted solution. See reconstitution and storage for the full handling reference.
Supplied strictly as a research reference material for in-vitro laboratory use. Not for human or veterinary use.
Frequently asked questions
Are BPC-157 and TB-500 the same class of peptide?
No. BPC-157 is a fully synthetic 15-amino-acid peptide. TB-500 corresponds to a fragment of thymosin beta-4, a naturally occurring 43-residue protein. They differ in origin, sequence, and molecular weight (about 1,420 vs 4,963 g/mol).
Why are they so often mentioned together?
Both appear in the same body of preclinical tissue-model literature, so researchers reviewing that literature encounter them side by side. Co-occurrence in a literature set is not structural similarity.
Does one Certificate of Analysis cover both?
No. A COA is lot-specific and compound-specific. Each vial of each compound has its own report confirming that exact lot by mass spectrometry and HPLC.