BPC-157 and TB-500 are two distinct research reference materials that are often listed side by side and are easy to confuse, partly because they are sometimes sourced together. This page compares them on identity alone, meaning their names, registry numbers, molecular descriptions, and sequences, so the two can be told apart from the certificate rather than from the label.
How the two compounds differ at a glance
At the level of identity, these are two separate materials. BPC-157 has a single, well-defined registry entry. TB-500 is a market name that can point to more than one molecule, so it carries more than one registry number depending on which form is in the vial.
| Property | BPC-157 | TB-500 (market name) |
|---|---|---|
| Compound class | Synthetic pentadecapeptide (15 residues) | Either full-length thymosin beta-4 or the Ac-LKKTETQ heptapeptide |
| CAS registry | 137525-51-0 | 77591-33-4 (thymosin beta-4) or 885340-08-9 (Ac-LKKTETQ) |
| Molecular formula | C62H98N16O22 | C212H350N56O78S or C38H68N10O14 |
| Approx. molar mass | ~1419.5 g/mol | ~4963 g/mol or ~889 g/mol |
Compound identity and CAS registry
BPC-157 resolves to one registry entry, CAS 137525-51-0. It is a synthetic pentadecapeptide, that is, a single chain of 15 amino-acid residues, and the same CAS number appears consistently across chemical registries and supplier catalogues.
TB-500 is where the ambiguity sits. The name is used in the market for two different molecules. One is the full-length thymosin beta-4 peptide, CAS 77591-33-4. The other is a shorter synthetic heptapeptide, Ac-LKKTETQ, CAS 885340-08-9, which corresponds to a short segment of the thymosin beta-4 sequence. Because a single label can refer to either, the registry identity of any given TB-500 vial is read from its certificate of analysis, not assumed from the name.
Molecular formula, molar mass, and structure
BPC-157 has the molecular formula C62H98N16O22 and a molar mass of roughly 1419.5 g/mol. As a 15-residue peptide, it sits well below the size of a small protein.
The two TB-500 forms differ substantially in size. Full-length thymosin beta-4 has the formula C212H350N56O78S and a molar mass of about 4963 g/mol, consistent with a peptide of 43 residues. The Ac-LKKTETQ heptapeptide has the formula C38H68N10O14 and a molar mass near 889 g/mol. The gap between about 889 and about 4963 g/mol is large enough that mass measurement alone separates the two TB-500 forms.
Amino-acid sequence
BPC-157 has the one-letter sequence GEPPPGKPADDAGLV, written in three-letter form as Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val.
The TB-500 heptapeptide form has the short sequence Ac-LKKTETQ, that is, Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln, carrying an N-terminal acetyl group. This segment corresponds to residues 17 to 23 of the thymosin beta-4 sequence. The full-length thymosin beta-4 form is a longer peptide of 43 residues and is not reproduced here. The sequences are the clearest identity marker: BPC-157 and either TB-500 form share no common chain.
Confirming identity and purity by LC-MS
Because TB-500 can refer to more than one molecule, the name printed on a label is not sufficient on its own. The reliable record is the analytical certificate. Each batch catalogued here is characterized by liquid chromatography and mass spectrometry (LC-MS) at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, which reads the measured mass against the expected molar mass for the stated sequence and reports an estimated purity figure. For a TB-500 material in particular, that certificate is what resolves whether the vial holds the full-length thymosin beta-4 peptide or the shorter Ac-LKKTETQ heptapeptide.
Which one is catalogued at livvmore
At livvmore, BPC-157 is catalogued on its own as BPC-157, with its full identity record on the BPC-157 research profile. TB-500 is not catalogued as a standalone item. It appears only inside Wolverine (BPC-157 + TB-500), and its registry and sequence details are set out on the TB-500 identity page.
For laboratory research use only. Not for human or veterinary use.
Frequently asked questions
Are BPC-157 and TB-500 the same compound?
No. They are separate reference materials with different names, CAS numbers, molecular formulas, molar masses, and sequences. They belong to different molecular classes and share no common chain.
Why does TB-500 have more than one CAS number?
TB-500 is a market name rather than a single defined molecule. It can refer to full-length thymosin beta-4 (CAS 77591-33-4) or to the shorter Ac-LKKTETQ heptapeptide (CAS 885340-08-9). The registry identity of a specific vial is read from its certificate of analysis.
How large is each molecule by molar mass?
BPC-157 is about 1419.5 g/mol. The TB-500 heptapeptide form is near 889 g/mol, while the full-length thymosin beta-4 form is about 4963 g/mol.
How is a batch’s identity confirmed?
By LC-MS at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, which compares the measured mass to the expected molar mass for the stated sequence and reports an estimated purity value.
Can TB-500 be catalogued on its own at livvmore?
No. It is catalogued only within Wolverine (BPC-157 + TB-500). BPC-157 is the item catalogued as a standalone material.