Research comparison · Research use only

BPC-157 vs TB-500: What the Research Literature Describes

By BioLabs Research · Last reviewed October 2026

Two short synthetic peptides, compared on identity: where each comes from, how their sequences and masses differ, which laboratory models the published literature uses, and how regulators list them.

BPC-157 and TB-500 are often named together. Both are short synthetic peptides, both are supplied for laboratory research only, and neither is an approved drug. Beyond that they have little in common. This page compares them on identity and on what the published literature describes, without making any claim about effects in people or animals.

Origins

BPC-157 is a 15-amino-acid fragment of BPC, a larger protein (Mr 40,000) isolated from gastric juice^[1]. Its sequence is Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, CAS 137525-51-0^[2].

TB-500 is a catalog name. When analytical chemists examined a product sold as TB-500, they identified Ac-LKKTETQ in it: the N-terminally acetylated fragment matching residues 17–23 of thymosin beta-4 (Tβ4)^[3]. Tβ4 itself is a naturally occurring 43-residue peptide encoded by the TMSB4X gene^[4]. TB-500 and Tβ4 are related, but they are not the same compound.

At a glance

Formula, weight and identifiers are from PubChem^[2][5]; parent molecules from the original literature and UniProt^[1][4][3]. Current prices are on each product page.

Sequence and structure

The two sequences share no motif. BPC-157 is proline-rich, with four prolines including a run of three, and it carries three acidic residues (one glutamate, two aspartates) against one lysine. TB-500 carries two lysines, two threonines, one glutamate and one glutamine, and its first residue is acetylated, which removes the free N-terminal amine^[5].

TB-500's sequence sits inside Tβ4's actin-binding region. Tβ4 binds single actin molecules (G-actin) and keeps them from assembling into filaments^[4], and it was shown in 1991 to be identical to Fx, a previously described actin-sequestering peptide^[6]. Mutational work mapped part of the actin-binding site to a hexapeptide motif at residues 17–22 (LKKTET), with lysine 18 among the residues contacting actin^[7]. The TB-500 fragment, residues 17–23, spans that motif.

Mass: how a lab tells them apart

Because the masses are far apart, mass spectrometry separates the three molecules unambiguously: about 1419.5 for BPC-157, about 889.0 for TB-500^[2][5] and about 4963 for full-length Tβ4^[8]. A lot's MS result therefore settles which compound is in the vial, and a result near 4963 describes full-length Tβ4 rather than the TB-500 fragment. HPLC with high-resolution MS is the approach used to characterize the TB-500 fragment in the analytical literature^[3].

What kinds of models the literature uses

The published work on the two compounds sits in different laboratory traditions. The descriptions below cover study designs only; they are not evidence of safety or efficacy in people or animals.

• BPC-157: isolation chemistry and cell and tissue preparations. The founding paper describes BPC's isolation from gastric juice and its 15-residue fragment^[1]. Later laboratory work includes cultured tendon fibroblasts isolated from rats, in which receptor expression was measured^[9], and isolated rat aorta, used to study vasomotor tone and nitric oxide signaling markers^[10].
• TB-500 and Tβ4: protein biochemistry and analytical chemistry. Tβ4 research centers on actin binding, measured with purified proteins and engineered variants that map which residues matter^[6][7]. The TB-500 fragment itself was synthesized as a reference material and characterized as an analytical reference material^[3].

Why identity checks matter for both

Catalog names travel faster than chemistry. The analytical study of TB-500 is itself an example: an analytical laboratory used high-resolution mass spectrometry to identify Ac-LKKTETQ in a product sold under that name, and synthesized the fragment as a reference^[3]. Synthetic peptides can also carry deletion sequences, oxidized residues and counter ions such as trifluoroacetate, which can distort laboratory results^[11]. For either compound, the sequence and mass on the lot's MS report, matched to the lot number on the vial, are what identify the material.

Comparisons in popular discussion often go beyond what this literature supports. The two compounds come from different parent molecules, have unrelated sequences, and have been studied with different methods.

Regulatory status side by side

• FDA approval: Drugs@FDA lists no approved drug product containing BPC-157, TB-500 or thymosin beta-4^[12].
• Compounding: FDA lists both BPC-157 and the thymosin beta-4 fragment (LKKTETQ) among nominated bulk substances whose nominations were withdrawn, with its descriptions of potential safety risks retained^[13]. Neither is on the 503A bulks list in 21 CFR 216.23^[14].
• Sport: the WADA 2026 Prohibited List names BPC-157 under S0 and thymosin-β4 and its derivatives, such as TB-500, under S2^[15].

For the wider picture, see are peptides legal? and are peptides safe?.

Quality and documentation

Both compounds are supplied as lyophilized research material. Lab COA PDFs are published per product where available (others on request); where provided on the lot COA, it shows HPLC area percent at a stated wavelength and MS identity, with the laboratory and test date. Identity data for each compound is on its product page: BPC-157 and TB-500. Lab COA PDFs are published per product where available in our COA library (others on request), and how to read a peptide COA explains each field. Storage conditions are on each SDS. For background, see What are peptides?.

Frequently asked questions

Are BPC-157 and TB-500 the same peptide?

No. BPC-157 is a 15-residue fragment of a gastric juice protein. TB-500 is Ac-LKKTETQ, an acetylated 7-residue fragment of thymosin beta-4. Their sequences, formulas and masses differ.

Is TB-500 the same as thymosin beta-4?

No. Thymosin beta-4 is the full 43-residue peptide of about 4963 g/mol. TB-500 is a 7-residue fragment matching residues 17–23, about 889 g/mol.

How can a lab tell BPC-157 and TB-500 apart?

By mass spectrometry. BPC-157 is about 1419.5 g/mol and TB-500 about 889.0 g/mol, so the MS result on a lot's COA identifies which compound is in the vial.

Are BPC-157 or TB-500 FDA approved?

No. Drugs@FDA lists no approved drug product containing either compound. BioLabs Research sells both for laboratory research only.

Where can I get a COA for either compound?

Lab COA PDFs are published per product where available in our COA library; others on request. Quote the lot number printed on the vial.

For laboratory research use only. Not for human or veterinary use. Not a drug, food, cosmetic or dietary supplement, and not intended to diagnose, treat, cure or prevent any condition. Nothing on this page is medical or legal advice.

References

1. Sikirić P, Petek M, Rucman R, et al. A new gastric juice peptide, BPC. […] J Physiol Paris. 1993;87(5):313–327. doi:10.1016/0928-4257(93)90038-u. PMID 8298609. pubmed.ncbi.nlm.nih.gov/8298609
2. National Center for Biotechnology Information. PubChem Compound Summary for CID 9941957 (BPC-157). pubchem.ncbi.nlm.nih.gov/compound/9941957
3. Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500 […]. Drug Test Anal. 2012;4(9):733–738. doi:10.1002/dta.1402. PMID 22962027. pubmed.ncbi.nlm.nih.gov/22962027
4. UniProt Consortium. UniProtKB P62328, Thymosin beta-4 (human). www.uniprot.org/uniprotkb/P62328/entry
5. National Center for Biotechnology Information. PubChem Compound Summary for CID 62707662 (TB-500, Ac-LKKTETQ). pubchem.ncbi.nlm.nih.gov/compound/62707662
6. Safer D, Elzinga M, Nachmias VT. Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable. J Biol Chem. 1991;266(7):4029–4032. PMID 1999398. pubmed.ncbi.nlm.nih.gov/1999398
7. Van Troys M, Dewitte D, Goethals M, Carlier MF, Vandekerckhove J, Ampe C. The actin binding site of thymosin beta 4 mapped by mutational analysis. EMBO J. 1996;15(2):201–210. PMID 8617195. pubmed.ncbi.nlm.nih.gov/8617195
8. National Center for Biotechnology Information. PubChem Compound Summary for CID 45382195 (thymosin beta-4). pubchem.ncbi.nlm.nih.gov/compound/45382195
9. Chang CH, Tsai WC, Hsu YH, Pang JH. Pentadecapeptide BPC 157 […] growth hormone receptor expression in tendon fibroblasts. Molecules. 2014;19(11):19066–19077. doi:10.3390/molecules191119066. PMID 25415472. pubmed.ncbi.nlm.nih.gov/25415472
10. Hsieh MJ, Lee CH, Chueh HY, et al. […] BPC 157 on vasomotor tone and the […] Src-Caveolin-1-endothelial nitric oxide synthase pathway. Sci Rep. 2020;10(1):17078. doi:10.1038/s41598-020-74022-y. PMID 33051481. pubmed.ncbi.nlm.nih.gov/33051481
11. D'Hondt M, Bracke N, Taevernier L, et al. Related impurities in peptide medicines. J Pharm Biomed Anal. 2014;101:2–30. doi:10.1016/j.jpba.2014.06.012. PMID 25044089. pubmed.ncbi.nlm.nih.gov/25044089
12. US Food and Drug Administration. Drugs@FDA: FDA-Approved Drugs (database). www.accessdata.fda.gov/scripts/cder/daf
13. US Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
14. 21 CFR 216.23, bulk drug substances that can be used to compound under section 503A (eCFR). www.ecfr.gov/current/title-21/section-216.23
15. World Anti-Doping Agency. The 2026 Prohibited List (in force 1 January 2026). www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf