The question of BPC-157 vs TB-500 comes up often because the two peptides are listed side by side in research catalogues and discussed together online. In chemical terms, though, they have almost nothing in common. This comparison covers origin, sequence, identity data and the shape of each research literature, so that laboratories can choose the right material for a given study design.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.
For a fuller introduction to both compounds, start with our BPC-157 and TB-500 research overview.
At a glance
- Name: BPC-157 / TB-500
- Synonyms: Body Protection Compound 157 / thymosin beta-4 fragment
- Sequence: GEPPPGKPADDAGLV / commonly described as Ac-LKKTETQ, confirm against analytical data
- Molecular formula: C62H98N16O22 / confirm from analytical data
- Molecular weight: 1419.5 g/mol / confirm from analytical data
- CAS number: 137525-51-0 / 885340-08-9
- Form: Lyophilised powder
- Storage: 2-8°C, dark, upright, do not freeze. Keep sealed until use.
Origin
BPC-157 was introduced by a research group at the University of Zagreb in the early 1990s. They described it as a partial sequence of a protein isolated from human gastric juice and named it Body Protection Compound. The peptide studied today is a synthetic 15-residue sequence.
TB-500 has a different lineage. It relates to thymosin beta-4, a 43-residue protein first sequenced from calf thymus in 1981 and later found in most mammalian cells. The TB-500 name is usually applied to a synthetic acetylated fragment of the thymosin beta-4 actin-binding region, although it has also been used for the full-length protein. Our explainer on what TB-500 is discusses this ambiguity.
Sequence and structure
BPC-157 has the sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val. It is rich in proline and contains several acidic residues, which together influence its conformation and its reported stability in acidic conditions. It has a defined formula, C62H98N16O22, and a molecular weight of about 1419.5 g/mol for the free acid.
The fragment most often sold as TB-500, Ac-LKKTETQ, is shorter at seven residues and is basic in character because of its two lysines. It corresponds to residues 17 to 23 of thymosin beta-4, part of the region that contacts actin. Because the TB-500 name covers more than one possible molecule, its formula and mass should be read from the analytical data of the specific material rather than assumed.
Sequence homology
There is no meaningful sequence similarity between the two peptides. They do not belong to the same protein family, and neither is a fragment of the other. Any similarity is in the research themes they have been investigated for, not in their chemistry.
Research literature compared
- Volume and source: BPC-157 literature is dominated by a single research group. Thymosin beta-4 has been studied by many independent laboratories worldwide.
- Model systems: both have been examined mainly in cell culture and rodent models. Thymosin beta-4 research also includes biochemical work on actin binding dating back to the early 1990s.
- Mechanistic themes: BPC-157 papers frequently discuss the nitric oxide system and growth factor signalling. Thymosin beta-4 papers centre on actin sequestration, cell migration and blood vessel formation in experimental models.
- Clinical stage: no authorised medicine exists for either. Full-length thymosin beta-4 has been examined in early-phase investigational trials, while human data for BPC-157 are very limited.
These differences matter when interpreting findings. A result from a thymosin beta-4 study using the full-length protein cannot be transferred automatically to the seven-residue fragment, and a BPC-157 result from one group carries more weight once it has been reproduced elsewhere.
Single compounds or a blend?
Some catalogues, including ours, list a BPC-157 / TB-500 blend alongside the individual peptides. The blend suits experiments where the combination is the variable under study. For mechanistic work, where an observation needs to be attributed to one molecule, separate vials of BPC-157 and TB-500 give cleaner control. A blend has no single CAS number, formula or molecular weight, so identity relies on the analytical data showing each component.
Analytical checks for both
For either peptide, the same two analyses establish identity and purity. HPLC shows the proportion of the main peak relative to synthesis-related impurities, and our catalogue specification is >99% by HPLC. Mass spectrometry confirms that the main component has the expected mass. For TB-500 in particular, the mass spectrum is the quickest way to tell a fragment from the full-length protein. Our guide to reading a peptide certificate of analysis walks through both.
Storage
Both peptides are supplied lyophilised, and our storage recommendation is the same for each: 2-8°C, protected from light, upright and not frozen, with the vial sealed until use.
View BPC-157, TB-500 or the BPC-157 / TB-500 blend in the catalogue.
Frequently asked questions
What is the main difference between BPC-157 and TB-500?
They come from different sources. BPC-157 is a 15-residue peptide described as a partial sequence of a gastric juice protein. TB-500 relates to thymosin beta-4, an intracellular actin-binding protein, and usually refers to a short acetylated fragment of it.
Are BPC-157 and TB-500 structurally related?
No. They share no meaningful sequence similarity and belong to no common protein family.
Which has more independent research?
Thymosin beta-4, the parent of TB-500, has been studied by many independent groups. BPC-157 research is concentrated in one group and is almost entirely preclinical.
Does a BPC-157 / TB-500 blend have its own CAS number?
No. A blend is a mixture of two separate peptides, so it has no single CAS number, formula or molecular weight. Each component should be identifiable in the analytical data.
Is either peptide an approved medicine?
No. Neither BPC-157 nor TB-500 is an authorised medicine in the UK. Our materials are for laboratory research use only.
References
- Sikiric P, Seiwerth S, Rucman R, et al. Brain-gut axis and pentadecapeptide BPC 157: theoretical and practical implications. Current Neuropharmacology, 2016.
- Low TL, Hu SK, Goldstein AL. Complete amino acid sequence of bovine thymosin beta 4. Proceedings of the National Academy of Sciences USA, 1981.
- Safer D, Elzinga M, Nachmias VT. Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable. Journal of Biological Chemistry, 1991.
- Goldstein AL, Hannappel E, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine, 2005.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.