BPC-157 + TB-500 — identity, handling and published literature

A two-component research peptide blend, presented as a co-lyophilised powder in a sealed glass vial: the synthetic pentadecapeptide BPC-157 and TB-500, the N-acetylated 17–23 fragment of thymosin β4. The two are separate molecules sharing a vial, not a conjugate, salt or complex, and each carries its own identity, its own literature and its own regulatory classification.

Presentation and physical properties

The vial is filled and labelled by total peptide mass. Both components are supplied as a white to off-white lyophilised cake or powder; a collapsed, shrunken or discoloured cake indicates a compromised lyophilisation or a breach of the vial’s vacuum and is a reason to reject the vial rather than to reconstitute it.

BPC-157 is a 15-residue linear peptide, H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH (single-letter GEPPPGKPADDAGLV), corresponding to a partial sequence of human gastric juice protein BPC. It carries neither cysteine nor any aromatic residue, and its three consecutive proline residues at positions 3–5 give it a conformationally constrained backbone. Counting ionisable side chains together with the free termini, it is net anionic at neutral pH: one glutamate, two aspartates and the C-terminal carboxylate against one lysine and the free N-terminal amine.

TB-500, as the term is used commercially, is not full-length thymosin β4. Esposito and colleagues characterised material sold under that name by high-resolution mass spectrometry and identified it as the N-terminally acetylated 17–23 fragment of human thymosin β4, Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH (Ac-LKKTETQ), a seven-residue peptide spanning the actin-binding motif [13]. Full-length thymosin β4 is a 43-residue, N-acetylated protein of roughly 4,963 g/mol — some 5.6 times the mass of the heptapeptide. The distinction governs how the literature below is read and is set out again under Evidence gaps and limitations. Ac-LKKTETQ likewise contains no cysteine and no aromatic residue.

Both components are freely soluble in water and in aqueous buffers at neutral pH; neither requires an organic co-solvent or acidification at the concentrations reached by ordinary vial reconstitution. Because their molecular masses differ by a factor of about 1.6, an equal-mass blend is not an equimolar blend — a point developed in the arithmetic below.

Reconstitution arithmetic

Reconstitution is a division. The mass stated on the label divides by the volume of diluent introduced, and the quotient is the concentration of the resulting solution. Lyophilised peptide of this order occupies a negligible volume, so the final solution volume can be taken as the diluent volume without material error.

For a vial labelled 20 mg of total peptide:

The arithmetic above describes the blend as a whole. Per-component concentration depends on the ratio in which the vial was filled, and that ratio is a property of the individual vial’s specification — it must be read from the vial or its accompanying documentation, not assumed. Where a 20 mg vial has been filled as an equal 10 mg + 10 mg split, the per-component figures are:

Equal mass is not equal molarity. At 10 mg/mL each, BPC-157 (1,419.5 g/mol) is approximately 7.05 mmol/L while Ac-LKKTETQ (889.0 g/mol) is approximately 11.25 mmol/L — a molar ratio near 1 : 1.6 in favour of the shorter peptide. Any experimental design expressed in molar terms has to convert from mass explicitly rather than treating a “1:1 blend” as equimolar.

These figures are concentrations of a prepared solution. They are not, and must not be read as, a target amount for any purpose.

Storage and stability

Sealed lyophilised powder is the stable form. Long-term storage at −20 °C, desiccated and protected from light, is the standard condition for peptides of this type; brief excursions to ambient temperature during transit are tolerated by the dry cake and are the reason lyophilisate rather than solution is shipped. Vials should be allowed to reach room temperature before the stopper is pierced, so that atmospheric moisture does not condense onto cold powder.

Reconstituted solution is the unstable form. Aqueous peptide solutions are held refrigerated at 2–8 °C and protected from light, and repeated freeze–thaw cycling should be avoided — where a solution is to be kept beyond short-term use, single-use aliquots frozen once are preferable to repeated withdrawal from one container. The choice of diluent affects hold time independently of the peptide: bacteriostatic water contains 0.9 per cent benzyl alcohol as a preservative and permits multiple withdrawals, whereas sterile water contains no preservative and offers no microbiological hold at all.

Neither component contains cysteine, so neither is subject to disulfide scrambling; neither contains methionine, so neither carries the methionine-oxidation liability that full-length thymosin β4 does. The dominant degradation routes for both are hydrolytic and, in biological matrices, proteolytic. Mazzarino and colleagues, characterising a doping-control workflow across dried and liquid blood matrices, reported that BPC-157 and TB-500 were among the analytes showing complete degradation in serum, in contrast to their persistence in dried matrices across the study period [16]. That is a matrix-stability observation from an analytical method paper, and it bears directly on how samples containing either peptide must be handled between collection and analysis.

Analytical identity

Liquid chromatography coupled to mass spectrometry is the method of record for both components. Esposito and colleagues synthesised Ac-LKKTETQ and characterised it against commercial TB-500 material, and proposed a mass-spectrometric strategy for its detection in plasma and urine [13]. Kwok and colleagues published an LC-MS method covering seven bioactive peptides including this fragment in equine plasma [14]. Rahaman and colleagues quantified TB-500 together with its metabolites by UHPLC-Q-Exactive Orbitrap MS/MS in in-vitro systems and in rats [15], and Mazzarino and colleagues report a harmonised blood-matrix workflow covering 54 prohibited peptidic and non-peptidic compounds, BPC-157 and TB-500 among them [16].

Two practical constraints follow from the sequences themselves. Neither peptide contains tryptophan, tyrosine or phenylalanine, so ultraviolet quantification at 280 nm is not available for either — content determination has to rely on peptide-bond absorbance near 214 nm, on quantitative amino acid analysis, or on gravimetric peptide content, and a laboratory that assumes an A280 route will find no signal to work with. And because the vial contains two intended species, chromatographic characterisation of a blend must resolve and report each component separately: a single area-percent figure for a two-peptide mixture describes the combined intended peaks and conveys nothing about the ratio between them or about the impurity profile of either. Identity work on this presentation therefore means two identifications and two content figures, not one.

What the published literature investigated

The blend as a blend

One published study has investigated the two peptides administered together. Biçer and colleagues transected and repaired the Achilles tendon in 32 rats, allocating animals to control, BPC-157, TB-500 or combined groups over four weeks, and assessed the outcome biomechanically and histopathologically [1]. The authors reported higher maximum load to failure in the BPC-157 and TB-500 groups than in controls, reaching statistical significance in the TB-500 group, and reported improved histopathological parameters and extracellular matrix organisation in the treatment groups during early repair. This is the only identified study in which the combination itself was a study arm, and it is a rodent study.

Rodent work on BPC-157

Staresinic and colleagues transected the rat Achilles tendon and reported improved biomechanical, functional and histological measures in treated animals, with increased fibroblast and collagen formation, alongside an in-vitro arm on cultured tendocytes [2]. The broader BPC-157 rodent literature is large, spans gastrointestinal, vascular, musculoskeletal and central nervous system injury models, and originates predominantly from a single research group in Zagreb — a concentration of provenance that the recent review literature identifies as a limitation of the corpus rather than a criticism of any individual paper [17][19][20].

Rodent work on thymosin β4 and its actin-binding fragment

Philp and colleagues examined both full-length thymosin β4 and a synthetic peptide containing its actin-binding domain in dermal wound models in db/db diabetic mice and in aged mice, reporting effects on keratinocyte migration, wound contraction and collagen deposition [4]. Sosne and colleagues reviewed the evidence that short sequences within thymosin β4, including the LKKTETQ motif, account for a subset of the parent protein’s activities [6] — the structural premise on which the commercial fragment rests, and the reason the fragment exists at all.

In vitro work

Chang and colleagues reported that BPC-157 accelerated outgrowth from rat tendon explants, increased survival of cultured tendon fibroblasts under oxidative stress, and increased cell migration in a concentration-dependent manner, with effects associated with FAK–paxillin pathway activation [3]. Shah and colleagues reported that thymosin β4 inhibited PDGF-BB-induced activation, proliferation and migration of human hepatic stellate cells, attributing the effect to its actin-binding domain [5].

Human studies of BPC-157

Two small human reports have been published, both by the same group and neither controlled. Lee and Padgett conducted a retrospective chart review of 16 patients who had received intra-articular injection for knee pain, of whom 12 had received BPC-157 alone; the review was a telephone follow-up with no control group and no blinding [7]. Lee and Burgess subsequently reported a pilot intravenous safety assessment in two healthy adults, measuring cardiac, hepatic, renal, thyroid and glucose biomarkers before and after infusion and reporting no measurable change and no adverse effects [8]. Two participants is a case series, not a safety dataset.

BPC-157 was taken into clinical development under the codes PL-10, PLD-116 and PL-14736, principally for inflammatory bowel disease, and the review literature records that programme [17][18]. Mateescu and colleagues state that pharmaceutical development remains rudimentary, with no approved formulation, no validated regimen and no completed Phase II clinical trial [18]. No completed controlled trial result has been published.

Human studies of thymosin β4 — the parent protein, not TB-500

Full-length thymosin β4 has a genuine controlled human trial base, and it belongs to that molecule rather than to the heptapeptide in this vial. Ruff and colleagues reported a randomised, placebo-controlled single- and multiple-dose study of intravenous thymosin β4 in healthy volunteers [9]. Guarnera and colleagues reported a European prospective randomised multicentre study in venous ulcers [10] and a subsequent Phase II randomised multicentre study [11]. Sosne and colleagues reported a Phase II randomised, double-masked, placebo-controlled trial of a 0.1 per cent thymosin β4 ophthalmic formulation (RGN-259) in severe dry eye, in nine patients over 56 days [12]. Wang and colleagues reported a first-in-human, randomised, double-blind Phase I study of recombinant human thymosin β4 in 54 single-dose and 30 multiple-dose healthy Chinese volunteers, concluding that the recombinant protein was well tolerated at the doses studied [21].

Every one of these studies used the 43-residue protein or a formulation of it. None used Ac-LKKTETQ.

Review literature

Gwyer and colleagues reviewed BPC-157 in musculoskeletal soft tissue models [19]; Seiwerth and colleagues reviewed the wound-healing corpus [20]; McGuire and colleagues published a narrative review addressing both the reported findings and the risks [17]; Mateescu and colleagues addressed biopharmaceutical and translational development barriers [18]; and Mendias and colleagues reviewed approved and unapproved peptide therapies in the musculoskeletal and athletic context, covering thymosin β4 and TB-500 among others [22].

Evidence gaps and limitations

No controlled human trial of the combination exists. Not a small one, not an unpublished one that can be pointed at, not a trial of a comparable blend. The combination has been studied once, in 32 rats, over four weeks [1]. Any statement about how the two peptides behave together in humans is an extrapolation from that single rodent study and from separate literatures on each component.

Neither component has a completed randomised controlled trial in its own right. For BPC-157 the human record consists of one retrospective 16-patient chart review with no control arm [7] and one two-participant infusion safety pilot [8]. Neither design can support an inference about effect, and the second cannot support an inference about safety at population scale. A clinical development programme existed and did not produce a published completed Phase II result [18].

The human trials in the reference list below are trials of a different molecule. References [9] through [12] and [21] concern full-length thymosin β4, a 43-residue N-acetylated protein of roughly 4,963 g/mol. TB-500 as supplied is Ac-LKKTETQ, seven residues and 889.0 g/mol — approximately 18 per cent of the parent by mass, comprising the actin-binding motif and nothing else [13]. The fragment has no published human trial of any design. Evidence that the parent protein was tolerated in healthy volunteers, or that an ophthalmic formulation of it met endpoints in a nine-patient Phase II study, is evidence about the parent protein. It does not transfer to the fragment, and treating it as though it does is the single most common error in secondary writing about this substance.

Provenance is concentrated. A large share of the BPC-157 preclinical corpus originates from one research group, and independent replication of the principal findings is limited. This is noted in the recent review literature [17][18] and is a structural feature of the evidence base rather than a defect in any one paper.

There is no published human pharmacokinetic dataset for either component — no absorption, distribution, metabolism or elimination profile in humans against which exposure could be reasoned about. Metabolite work for TB-500 exists in vitro and in rats [15]. There is no chronic toxicology package, no reproductive toxicology, no carcinogenicity assessment and no immunogenicity dataset in the public literature for either peptide. The FDA’s stated concerns when placing both on its restricted compounding list included immunogenicity for certain routes and the characterisation of peptide-related impurities.

Blend-specific gaps compound the above. No published work characterises pharmacokinetic or physicochemical interaction between the two peptides in a shared solution, no stability study of the co-lyophilised mixture is available in the literature, and no ratio has been established as standard. Two under-characterised substances in one vial produce a combined uncertainty larger than either alone.

Regulatory and standards position

United Kingdom

Neither BPC-157 nor TB-500 holds a marketing authorisation from the MHRA, and neither appears in any UK-authorised medicinal product. Neither is a controlled drug under the Misuse of Drugs Act 1971, and neither is scheduled under the Misuse of Drugs Regulations 2001; possession and supply as a laboratory chemical are not offences under that legislation. Supply is governed instead by the Human Medicines Regulations 2012 and by the “medicinal product by presentation” limb carried over from Article 1(2) of Directive 2001/83/EC — the position set out in MHRA Guidance Note 8 and in Ter Voort (C-219/91). It is the claim made about a substance, not the molecule, that brings it within the definition of a medicinal product. A research chemical described in terms of identity, composition and handling is outside that definition; the same chemical described in terms of what it does to a person is within it, and is then an unauthorised medicinal product.

European Union

Neither component holds a centralised or national marketing authorisation in the EU. The presentation limb of Article 1(2) applies on the same terms as above.

United States

Neither component is an FDA-approved drug and neither has a USP-NF monograph. Both were placed in Category 2 of the FDA’s interim list of bulk drug substances under section 503A of the FD&C Act — substances the agency identified as raising significant safety risks and therefore outside its enforcement-discretion policy for compounding — in the agency’s 2023 revision. The compounding position has been under active revision during 2026 and the FDA’s current published list should be consulted rather than any secondary account of it. USADA states that “there appears to be no legal basis for selling BPC-157 as a drug, food, or a dietary supplement, and the Food and Drug Administration (FDA) confirmed there is also no legal basis for compounding pharmacies to use BPC-157 in compounded medications.”

Anti-doping — the two components sit in different classes

This blend cannot be given a single WADA classification, because its components are prohibited under different sections of the Prohibited List, with different Specified status and therefore different sanction consequences. Both are prohibited at all times, in and out of competition.

BPC-157 — Section S0, Non-Approved Substances. It is named expressly in the 2026 List, which provides that the class “covers many different substances including but not limited to BPC-157, 2,4-dinitrophenol (DNP), ryanodine receptor-1-calstabin complex stabilizers [e.g. S-107, S48168 (ARM210)] and troponin activators (e.g. reldesemtiv and tirasemtiv)”. The List states that “All prohibited substances in this class are Specified Substances.”

TB-500 — Section S2.3, Growth Factors and Growth Factor Modulators. The 2026 List names, among the growth factors in that subsection, “Thymosin-ß4 and its derivatives e.g. TB-500”, and closes the subsection with “and other growth factors or growth factor modulators affecting muscle, tendon or ligament protein synthesis/degradation, vascularisation, energy utilization, regenerative capacity or fibre type switching”. Section S2 states that “All prohibited substances in this class are non-Specified Substances.”

The practical consequence of the split is that the two components attract different default sanction treatment under Article 10 of the World Anti-Doping Code, and a single vial exposes an athlete to both. Detection is established rather than theoretical: validated methods for the fragment in human plasma and urine [13], in equine plasma [14] and for TB-500 metabolites [15] are published, and a current harmonised workflow covers both BPC-157 and TB-500 in dried and liquid blood matrices [16].

Laboratory handling and safety

No harmonised GHS classification exists for either component, and no toxicological dataset adequate to support a hazard assessment has been published for either. Both should therefore be handled as substances of unknown toxicity: laboratory coat, nitrile gloves and eye protection, no eating or drinking in the working area, and preparation of solutions in a manner that avoids dispersing the dry powder. Lyophilised cake is light and prone to static; the vial should be opened without agitation and diluent introduced down the vial wall rather than directly onto the cake, which also limits foaming and the shear that foaming implies.

Reconstituted material should be labelled at the point of preparation with both component identities, the total and per-component concentration, the diluent used and the date, because a mixed-peptide solution is indistinguishable by inspection from a single-peptide one and the ratio cannot be recovered from an unlabelled vial. Glass and stopper should be inspected before use; a cracked vial or a lifted stopper compromises the vacuum and the contents with it.

Waste solution and used vials should be disposed of through the laboratory’s chemical waste stream, not to drain. Sharps used in reconstitution go to a sharps container.

References

1. Biçer O, Adanir O, Güleryüz Y, Balci EC, Dinçel YM, Yenigün MY, Aydin C, Bayrak BY. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: a histopathological and biomechanical study. Jt Dis Relat Surg. 2026;37:822–837. Rodent (rat Achilles tendon transection, n=32). PMID 42542926
2. Staresinic M, et al. Gastric pentadecapeptide BPC 157 accelerates healing of transected rat Achilles tendon and in vitro stimulates tendocytes growth. J Orthop Res. 2003;21:976–983. Rodent, with in vitro arm. PMID 14554208
3. Chang CH, Tsai WC, Lin MS, Hsu YH, Pang JH. The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. J Appl Physiol (1985). 2011;110:774–780. In vitro (rat tendon explants and cultured fibroblasts). PMID 21030672
4. Philp D, et al. Thymosin beta 4 and a synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db diabetic mice and in aged mice. Wound Repair Regen. 2003;11:19–24. Rodent (db/db and aged mice). PMID 12581423
5. Shah R, et al. Thymosin β4 inhibits PDGF-BB induced activation, proliferation, and migration of human hepatic stellate cells via its actin-binding domain. Expert Opin Biol Ther. 2018;18:177–184. In vitro (human hepatic stellate cells). PMID 30063851
6. Sosne G, et al. Biological activities of thymosin beta4 defined by active sites in short peptide sequences. FASEB J. 2010;24:2144–2151. Review. PMID 20179146
7. Lee E, Padgett B. Intra-articular injection of BPC 157 for multiple types of knee pain. Altern Ther Health Med. 2021;27(4):8–13. Human, retrospective chart review, 16 patients, no control group, no blinding. PMID 34324435
8. Lee E, Burgess K. Safety of intravenous infusion of BPC157 in humans: a pilot study. Altern Ther Health Med. 2025;31(5):20–24. Human, uncontrolled pilot, 2 participants. PMID 40131143
9. Ruff D, et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223–229. Human trial, Phase I — full-length thymosin β4, not TB-500. PMID 20536472
10. Guarnera G, et al. Thymosin beta-4 and venous ulcers: clinical remarks on a European prospective, randomized study. Ann N Y Acad Sci. 2007;1112:407–412. Human trial, randomised multicentre — full-length thymosin β4, not TB-500. PMID 17495250
11. Guarnera G, et al. The effect of thymosin treatment of venous ulcers. Ann N Y Acad Sci. 2010;1194:207–212. Human trial, Phase II randomised multicentre — full-length thymosin β4, not TB-500. PMID 20536470
12. Sosne G, et al. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. Cornea. 2015;34:491–496. Human trial, Phase II, 9 patients — full-length thymosin β4 (RGN-259), not TB-500. PMID 25826322
13. Esposito S, et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4:733–738. In vitro / analytical characterisation. PMID 22962027
14. Kwok WH, et al. Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry. Anal Bioanal Chem. 2013;405:2595–2606. In vitro / analytical method, equine plasma. PMID 23318763
15. Rahaman KA, et al. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. J Chromatogr B Analyt Technol Biomed Life Sci. 2024;1235:124033. In vitro and rodent. PMID 38382158
16. Mazzarino M, Colpaert T, Deventer K, Van Eenoo P. Rapid and harmonized analytical workflow for the determination of peptidic and non-peptidic doping agents in dried and liquid blood matrices. Analyst. 2026;151:4398–4413. In vitro / analytical method, human blood matrices. PMID 42328738
17. McGuire FP, et al. Regeneration or risk? A narrative review of BPC-157 for musculoskeletal healing. Curr Rev Musculoskelet Med. 2025;18:611–619. Review. PMID 40789979
18. Mateescu DM, et al. BPC-157 as an investigational peptide therapeutic: biopharmaceutical challenges, formulation strategies, and translational development barriers. Pharmaceutics. 2026;18. Review. PMID 42198317
19. Gwyer D, et al. Gastric pentadecapeptide body protection compound BPC 157 and its role in accelerating musculoskeletal soft tissue healing. Cell Tissue Res. 2019;377:153–159. Review. PMID 30915550
20. Seiwerth S, et al. Stable gastric pentadecapeptide BPC 157 and wound healing. Front Pharmacol. 2021;12:627533. Review. PMID 34267654
21. Wang X, et al. A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin β4 in healthy Chinese volunteers. J Cell Mol Med. 2021;25:8222–8228. Human trial, Phase I, 84 subjects — recombinant full-length thymosin β4, not TB-500. PMID 34346165
22. Mendias CL, et al. Safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance. Sports Med. 2026; online ahead of print. Review. PMID 41966639

Research use only

BPC-157 + TB-500 is supplied as a laboratory reagent for research use only. It is not a medicinal product, not a food, not a dietary supplement and not a cosmetic ingredient. It is not authorised by the MHRA, the EMA or the FDA for human or veterinary use, and no part of this page describes, recommends or implies any use in humans or animals.

Nothing on this page is a statement that either component treats, prevents, cures or otherwise affects any condition. Findings are reported as statements about the studies that made them, and a finding in a rodent or in cell culture is a fact about that experiment and not a prediction about anything else. Both components are prohibited in sport at all times under the WADA Prohibited List, in the different sections set out above. Purchasers are responsible for satisfying themselves that possession, storage and use are lawful in their jurisdiction and comply with their institution’s requirements.