BPC-157 and TB-500 are two of the most frequently discussed research peptides, and they are often mentioned in the same breath. Searches for bpc 157 peptides, tb 500 and bpc 157 tb500 reflect that pairing. Yet the two molecules have different origins, different sizes and different bodies of literature behind them. This overview sets out what each compound is, how they are characterised in the laboratory and what published preclinical work has examined, without drawing conclusions about effects in humans.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.
This page is the hub for our BPC-157 and thymosin cluster. For deeper reading, see what TB-500 is and how it relates to thymosin beta-4, a side-by-side comparison of BPC-157 vs TB-500, our explainer on thymosin alpha-1 vs thymosin beta-4 and a profile of the KPV peptide, an alpha-MSH fragment.
At a glance: BPC-157
- Name: BPC-157
- Synonyms: Body Protection Compound 157, pentadecapeptide BPC 157, PL 14736
- Sequence: Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val (GEPPPGKPADDAGLV)
- Molecular formula: C62H98N16O22
- Molecular weight: 1419.5 g/mol
- CAS number: 137525-51-0
- Form: Lyophilised powder
- Storage: 2-8°C, dark, upright, do not freeze. Keep sealed until use.
At a glance: TB-500
- Name: TB-500
- Synonyms: thymosin beta-4 fragment, synthetic thymosin beta-4 related peptide
- Sequence: commonly described as the acetylated actin-binding fragment of thymosin beta-4 (Ac-LKKTETQ); confirm against the supplied analytical data
- Molecular formula: see analytical data for the specific material
- Molecular weight: see analytical data for the specific material
- CAS number: 885340-08-9
- Form: Lyophilised powder
- Storage: 2-8°C, dark, upright, do not freeze. Keep sealed until use.
What is BPC-157?
BPC-157 is a synthetic linear peptide of 15 amino acids. The name stands for Body Protection Compound, a label introduced by the Croatian research group led by Predrag Sikiric at the University of Zagreb, which has produced most of the published work on the compound since the early 1990s. The group has described BPC-157 as a partial sequence of a larger protein they reported isolating from human gastric juice. The parent protein itself has not been widely characterised by independent groups, so in practice BPC-157 is studied as a defined synthetic sequence rather than as a fragment of a well-mapped natural protein.
Structurally, the sequence is notable for a run of three proline residues near the N-terminus and two adjacent aspartic acid residues in the middle. Proline-rich stretches restrict backbone flexibility, and the Sikiric group has repeatedly described the peptide as stable in gastric juice, which they offered as one reason for the interest in it. The free acid form has a molecular formula of C62H98N16O22 and a molecular weight of around 1419.5 g/mol. Some suppliers also offer an acetate or arginate salt, which changes the counter-ion but not the peptide sequence. When comparing materials, check which form a certificate of analysis refers to.
Where BPC-157 has been studied
Almost all published BPC-157 research is preclinical, meaning it was carried out in cell culture or in animal models, chiefly rats and mice. Reviews by the Sikiric group summarise rodent work on the gastrointestinal tract, including models of gastric lesions and intestinal anastomosis, as well as experiments on tendon, ligament and muscle tissue, blood vessel formation and interactions with the nitric oxide system. Other papers have investigated the peptide in rodent models relevant to the brain-gut axis and to dopaminergic and serotonergic signalling.
Two features of this literature are important for anyone reading it critically. First, a large proportion of the work comes from a single research group, and independent replication has been more limited. Second, controlled human data are very sparse. A compound code, PL 14736, appears in the literature in connection with early clinical development for inflammatory bowel conditions, but no regulator, including the MHRA, has authorised BPC-157 as a medicine. The material we supply is a research chemical and is not a medicine.
What is TB-500?
TB-500 is a name used in the research chemical market for a synthetic peptide related to thymosin beta-4, a naturally occurring 43-amino-acid protein. Thymosin beta-4 was first sequenced from bovine thymus by Low, Hu and Goldstein in 1981 and was later found to be present in most mammalian cell types. Its best characterised role is as a G-actin sequestering protein: it binds monomeric actin and regulates the pool available for filament assembly, which is central to cell shape and movement.
The term TB-500 is not a pharmacopoeial or INN name, and its exact meaning varies between sources. It is most commonly described as a short acetylated fragment corresponding to the actin-binding region of thymosin beta-4, often written as Ac-LKKTETQ (residues 17 to 23). Some suppliers have historically used the name for full-length synthetic thymosin beta-4. Because of this ambiguity, the identity of any TB-500 material should be judged by its analytical data, specifically the mass spectrum and HPLC trace, rather than by its name. Our article on what TB-500 is goes into this distinction in more detail.
Where thymosin beta-4 has been studied
The thymosin beta-4 literature is broader and more diverse than the BPC-157 literature, partly because the native protein is ubiquitous and has been studied by many independent groups. Reviews such as Huff and colleagues (2001) and Goldstein, Hannappel and Kleinman (2005) describe work on actin dynamics, cell migration, angiogenesis in cell and animal models, and responses in models of tissue injury in the skin, eye and heart. Some of this research focused on the full-length protein and some on specific fragments, including the actin-binding region and the N-terminal tetrapeptide Ac-SDKP, which has its own literature.
Full-length thymosin beta-4 has been examined in early-phase clinical trials sponsored by drug developers, including ophthalmic and dermal formulations. These are separate investigational products and do not imply anything about research-grade TB-500. Thymosin beta-4 is not an authorised medicine in the UK, and our material is supplied for laboratory research only.
BPC-157 and TB-500 compared
Although the two names are often paired, the molecules differ in nearly every respect that matters for a laboratory. Our full BPC-157 vs TB-500 comparison sets this out in detail, but the headline points are summarised below.
- Origin: BPC-157 is described as a partial sequence of a gastric juice protein, while TB-500 relates to thymosin beta-4, a ubiquitous intracellular actin-binding protein.
- Size: BPC-157 is a 15-residue peptide. TB-500 is usually described as a 7-residue acetylated fragment, while the parent thymosin beta-4 has 43 residues.
- Literature: BPC-157 research is concentrated in one group and is almost entirely preclinical. Thymosin beta-4 research spans many groups and includes early clinical studies of the full-length protein.
- Mechanistic focus: BPC-157 papers often discuss nitric oxide signalling and growth factor pathways. Thymosin beta-4 papers centre on actin sequestration and cell migration.
- Identity data: BPC-157 has a well-defined formula and molecular weight. For TB-500, identity should be confirmed from the analytical data of the specific material.
Why are BPC-157 and TB-500 paired in research catalogues?
The pairing is largely a matter of overlapping research themes. Both compounds have been investigated in rodent models involving soft tissue, blood vessel formation and cell migration, so researchers designing comparative in vitro or animal experiments sometimes want both on hand. That is the reason some suppliers, including us, list a combined product. The BPC-157 / TB-500 blend is a single lyophilised vial containing both peptides, which may suit researchers running experiments where the combination itself is the variable under study.
A blend is not a new chemical entity and does not have its own CAS number, molecular formula or molecular weight. Each component should be identifiable on the analytical data. For most mechanistic work, where the aim is to attribute an observation to a single compound, separate vials of BPC-157 and TB-500 give clearer experimental control.
Related peptides in this cluster
Discussions of TB-500 often lead to confusion with thymosin alpha-1, a completely different 28-residue peptide that happens to share the thymosin name because both were originally isolated from thymus extracts. Our article on thymosin alpha-1 vs thymosin beta-4 explains the history and the structural differences. Thymosin alpha-1 is notable because a version of it, thymalfasin, has been approved as a medicine in a number of countries outside the UK. Research-grade thymosin alpha-1 is a separate material and is not a medicine.
Another short peptide that often appears in the same research conversations is KPV, the C-terminal tripeptide Lys-Pro-Val of alpha-melanocyte-stimulating hormone. It has been investigated in cell and rodent models of intestinal and skin inflammation. See our KPV peptide profile for identity data and the key literature.
Quality and identity checks for research use
Because both compounds are synthetic peptides made by solid-phase synthesis, the main quality questions are the same: is the material the intended sequence, and how much of the vial is that sequence rather than synthesis by-products. Two analyses answer those questions.
- HPLC (high-performance liquid chromatography) separates the target peptide from related impurities such as truncated or deletion sequences. Purity is expressed as the area of the main peak as a percentage of all peaks detected. Our catalogue purity specification is >99% by HPLC.
- Mass spectrometry confirms that the main component has the expected molecular mass. For BPC-157, the observed mass should be consistent with a molecular weight of about 1419.5 g/mol. For TB-500, the observed mass tells you which form of the peptide you actually have.
Our guide on how to read a peptide certificate of analysis explains how to interpret these documents, and our research peptides UK buyer's guide covers wider supplier checks.
Storage and handling of lyophilised material
BPC-157 and TB-500 are supplied as lyophilised (freeze-dried) powders, which are considerably more stable than peptides in solution. Our storage recommendation for both is 2-8°C, protected from light, stored upright and not frozen, with the vial kept sealed until use. Moisture is the main enemy of lyophilised peptides, so allowing a cold vial to reach room temperature before opening reduces condensation. Our article on how to store lyophilised peptides covers the reasoning in more depth.
Standard laboratory practice applies: wear gloves and eye protection, label vials clearly with compound and date, and record storage conditions in your laboratory notebook so any later analytical findings can be interpreted in context.
Regulatory position in the UK
Neither BPC-157 nor TB-500 is an authorised medicinal product in the UK. Whether a product is regulated as a medicine depends on how it is presented and what it is said to do, which is why responsible suppliers describe these compounds strictly as laboratory research materials and avoid any claims about effects in people. Our article are peptides legal in the UK explains the framework in general terms. It is not legal advice.
Reading the literature critically
When reviewing published work on either peptide, a few questions help put findings in context. Was the study in cells, animals or people? Which form of the peptide was used: full-length thymosin beta-4, a fragment or BPC-157 as a specific salt? How large were the groups, and has the finding been reproduced by an independent laboratory? Was the material characterised analytically? Many early papers predate the routine reporting of purity and mass data, which makes cross-study comparison harder.
These questions do not diminish the research, but they matter when designing new experiments. A study that cannot state precisely which peptide was used is difficult to build on, which is one reason we emphasise identity data on every product page.
It is also worth separating mechanistic findings from descriptive ones. A cell culture experiment showing that thymosin beta-4 binds G-actin describes a molecular interaction that can be measured directly. A rodent study reporting faster closure of an experimental wound describes an outcome in a whole organism with many variables. Both are useful, but they answer different questions, and neither on its own predicts what would happen in a human.
Researchers who want to understand the field from first principles may find it helpful to start with the structural papers, such as the original thymosin beta-4 sequencing work, before moving to the larger body of animal studies and reviews. For BPC-157, the reviews from the Zagreb group provide the most complete map of what has been examined, and reading them alongside independent studies gives a fairer picture of how far the findings have travelled beyond one laboratory.
View BPC-157, TB-500 or the BPC-157 / TB-500 blend in the catalogue.
Frequently asked questions
Are BPC-157 and TB-500 the same thing?
No. BPC-157 is a 15-residue synthetic peptide described as a partial sequence of a gastric juice protein. TB-500 is a synthetic peptide related to thymosin beta-4, usually described as a short acetylated fragment of its actin-binding region. They differ in origin, size and the body of literature behind them.
What is the CAS number for BPC-157?
The CAS number for BPC-157 is 137525-51-0. Its molecular formula is C62H98N16O22 and its molecular weight is about 1419.5 g/mol.
What is the CAS number for TB-500?
The CAS number listed for our TB-500 is 885340-08-9. Because the TB-500 name has been used for more than one form of thymosin beta-4 related peptide, identity is best confirmed from mass spectrometry data.
Has BPC-157 been studied in humans?
Published BPC-157 research is almost entirely preclinical, carried out in cell culture and rodent models. It is not an authorised medicine in the UK, and our material is supplied for laboratory research only.
Why is there a BPC-157 / TB-500 blend?
Some researchers study the two peptides together in comparative experiments, so a combined vial is offered for convenience. A blend has no single CAS number or formula, and separate vials give clearer control when attributing observations to one compound.
How should BPC-157 and TB-500 be stored?
Both are lyophilised powders. We recommend 2-8°C, protected from light, upright and not frozen, with the vial kept sealed until use.
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: a thymic hormone that induces terminal deoxynucleotidyl transferase activity in thymocyte populations. Proceedings of the National Academy of Sciences USA, 1981.
- Huff T, Muller CS, Otto AM, Netzker R, Hannappel E. beta-Thymosins, small acidic peptides with multiple functions. International Journal of Biochemistry and Cell Biology, 2001.
- Goldstein AL, Hannappel E, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine, 2005.
- PubChem, National Center for Biotechnology Information. Compound records for BPC-157 and thymosin beta-4.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.