BPC-157 and TB-500: What the Research Literature Covers

BPC-157 and TB-500 are two synthetic research peptides that are routinely discussed together but are structurally and biologically unrelated: BPC-157 is a 15-residue sequence corresponding to a partial sequence of a protein described in human gastric juice, while TB-500 is a short acetylated fragment of thymosin β4, an endogenous actin-sequestering protein. Neither compound is approved by FDA for any indication. Both are supplied for laboratory research use only and are not for human or animal consumption.

Why the pairing is a catalogue convention, not a scientific one

The two peptides are grouped in supplier listings and forum discussion rather than in the primary literature. They originate from different laboratories, different decades, and different parent molecules, and they are characterised in largely non-overlapping assay systems. Published studies that administer both compounds in the same model are rare, which means there is no direct head-to-head experimental record to summarise. What follows compares the two separate literatures, not the compounds themselves.

Specifications

CAS numbers for both research peptides circulate chiefly through vendor catalogues rather than through primary literature, and the identifier for TB-500 in particular should be treated as catalogue metadata rather than as an analytical result.

Mechanism and study-model comparison

BPC-157: reported mechanism and research history

BPC-157 was characterised at the University of Zagreb as a stable partial sequence of a larger gastric protein. The mechanistic record is preclinical. In a 2011 study, Chang et al. worked in two systems that were both outside a living animal: tendon explants taken from rat Achilles tendon and cultured rat tendon fibroblasts. They reported accelerated outgrowth from the explants, increased fibroblast survival under hydrogen peroxide stress, and concentration-dependent fibroblast migration, while proliferation measured by MTT assay was not directly affected. They attributed the migratory response to phosphorylation of focal adhesion kinase and paxillin. In 2017, Hsieh et al. reported increased vessel density in vitro and in vivo, recovery of blood flow in a rat hind-limb ischaemia model, and increased vascular expression of VEGFR2, together with VEGFR2 internalisation and downstream Akt–eNOS signalling in cultured human vascular endothelial cells; endothelial tube formation was suppressed by the internalisation inhibitor dynasore. A separate strand of work from the originating group describes interaction with the nitric oxide system.

The methodological caveats are as important as the findings. Reviewing the literature and patent record in 2025, Józwiak et al. noted that most, if not all, studies remain limited to small animal models, and that the pharmacokinetic record consists of a single study in rats and dogs reporting an elimination half-life below 30 minutes. That review drew a published comment from Sikiric and colleagues at the originating group and a reply from the review authors in the same journal in 2025, and the exchange itself is a useful record of where the field disagrees.

Thymosin β4 and the fragment marketed as TB-500

Thymosin β4 is described by Goldstein, Hannappel and Kleinman in their 2005 review as the major actin-sequestering molecule in eukaryotic cells; it binds monomeric actin and is largely unstructured until it folds on binding. In 1999, Malinda et al. reported increased re-epithelialisation, greater wound contraction, and increased collagen deposition and angiogenesis in a rat full-thickness dermal wound model treated with the full-length protein. Philp et al. reported in 2003 that a seven-residue actin-binding motif from thymosin β4 — the sequence sold as TB-500 — promoted endothelial cell adhesion and migration and aortic ring sprouting, and that adding soluble actin at 5–50 nM inhibited the adhesion and sprouting responses; that experiment is the basis for isolating the heptapeptide at all. In cardiac models, Bock-Marquette et al. (2004) described a functional complex of thymosin β4 with PINCH and integrin-linked kinase resulting in Akt activation, and reported upregulated ILK and Akt activity after coronary artery ligation in mice. Smart et al. (2007) reported outgrowth from quiescent adult epicardial explants and discussed the cleavage product AcSDKP. Parts of this cardiac line, particularly claims about epicardial cell fate, have been contested in subsequent cardiology literature; the actin-sequestering biochemistry has not.

The unavoidable point for anyone reading a supplier listing: this body of work was almost entirely generated with full-length thymosin β4 or with defined synthetic fragments in defined assays. It is not interchangeable evidence for the acetylated heptapeptide sold as TB-500.

Identity ambiguity in material labelled TB-500

"TB-500" is a trade designation rather than a chemical name, and material sold under it has historically been either the acetylated heptapeptide Ac-LKKTETQ near 889 g/mol or the full 43-residue protein near 4963 g/mol. These differ by roughly a factor of five in mass and are not the same substance. Published molecular weights for the heptapeptide also vary between vendor listings, which is itself a signal that catalogue metadata should not be treated as analytical data. Mass spectrometry and HPLC results on a lot-specific certificate of analysis are the only way to establish which molecule is actually in a vial; see lab testing for what those reports contain and how to read them.

What this comparison does not establish

There is no adequate human efficacy data for either compound as supplied, and neither has an established mechanism in humans. The BPC-157 record is preclinical and confined largely to small animal models. The thymosin β4 record is broader and includes completed registered clinical work, but that work concerns a specific pharmaceutical formulation under investigational control, not research-grade powder. Ranking the two against each other would require comparative data that does not exist in the published literature.

Regulatory status

Neither BPC-157 nor TB-500 is approved by FDA. BPC-157 has been identified in FDA's review of bulk drug substances nominated for compounding under section 503A as a Category 2 substance. The composition of that list is revised periodically, and the current FDA listing, rather than any secondary source including this page, is the authority on its present status. In sport, BPC-157 has been named as an example in section S0 of the WADA Prohibited List from 2022, and thymosin β4 and its derivatives, including TB-500, are prohibited at all times; the current WADA Prohibited List is the authority there. All material described here is sold subject to our research use policy.

Handling and documentation

Both compounds ship as lyophilized powder and are handled as standard synthetic peptides: stored desiccated below freezing, protected from light and moisture, and equilibrated to room temperature before a vial is opened to limit condensation. Guidance on cold-chain and long-term storage is collected under peptide storage, laboratory preparation of stock solutions under reconstitution, and the associated concentration arithmetic in the peptide calculator.

How should lyophilized material of either peptide be stored?

As supplied, both are lyophilized powders and are kept desiccated at −20 °C, shielded from light and moisture. Short excursions to ambient temperature during shipping are ordinary for lyophilized peptides; repeated freeze–thaw cycling of prepared solutions is the more common cause of degradation.

Are BPC-157 and TB-500 chemically related?

No. They share no sequence homology, no parent protein, and no established common target. BPC-157 derives from a gastric protein sequence; TB-500 is a fragment of thymosin β4.

What should a certificate of analysis show for these compounds?

A lot-specific report with HPLC purity, a mass spectrometry result matching the expected molecular weight for the exact molecule named on the label, and identification of the analysing laboratory. For TB-500 in particular, the reported mass distinguishes the heptapeptide from full-length thymosin β4.

Is either compound approved or otherwise cleared for use?

Neither is FDA approved. Both are supplied strictly as research chemicals, are not for human or animal consumption, and are prohibited in sanctioned sport under the WADA Prohibited List.

References

1. Chang CH, Tsai WC, Lin MS, Hsu YH, Pang JH (2011). The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. Journal of Applied Physiology 110:774–780.
2. Hsieh MJ, Liu HT, Wang CN, Huang HY, Lin Y, Ko YS, Wang JS, Chang VH, Pang JS (2017). Therapeutic potential of pro-angiogenic BPC157 is associated with VEGFR2 activation and up-regulation. Journal of Molecular Medicine 95:323–333.
3. Józwiak M, Bauer M, Kamysz W, Kleczkowska P (2025). Multifunctionality and Possible Medical Application of the BPC 157 Peptide — Literature and Patent Review. Pharmaceuticals 18:185.
4. Goldstein AL, Hannappel E, Kleinman HK (2005). Thymosin β4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine 11:421–429.
5. Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK (2003). The actin binding site on thymosin β4 promotes angiogenesis. The FASEB Journal 17:2103–2105.
6. Malinda KM, Sidhu GS, Mani H, Banaudha K, Maheshwari RK, Goldstein AL, Kleinman HK (1999). Thymosin β4 accelerates wound healing. Journal of Investigative Dermatology 113:364–368.
7. Bock-Marquette I, Saxena A, White MD, DiMaio JM, Srivastava D (2004). Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature 432:466–472.
8. Smart N, Risebro CA, Melville AA, Moses K, Schwartz RJ, Chien KR, Riley PR (2007). Thymosin β4 induces adult epicardial progenitor mobilization and neovascularization. Nature 445:177–182.