Research Overview
BPC-157 and TB-500 are cross-shopped because the preclinical literature keeps putting them in the same models: transected rodent tendon, dermal wounds, ischemic muscle, cultured cells under stress. The two are structurally unrelated, and only one published rodent experiment has run them side by side (Bicer et al., Jt Dis Relat Surg 2026, PMID 42542926).
BPC-157 is a synthetic 15-residue peptide corresponding to a partial sequence of a protein described in human gastric juice (Staresinic et al., J Orthop Res 2003, PMID 14554208). TB-500 is not a protein: analytical work on material sold under that name identified an N-terminally acetylated fragment of thymosin beta-4, the 17 to 23 segment Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln (Esposito et al., Drug Test Anal 2012, PMID 22962027), the region described as the actin-binding and cell-migration site of the parent protein (Ho et al., J Chromatogr A 2012, PMID 23084823).
Because the name is applied in practice both to that fragment and to the full 43-residue protein, species identity is the first thing to settle in a study design. All findings below are cell, rodent or equine observations reported as research context only.
Structure and Class
BPC-157 is a pentadecapeptide, Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val (GEPPPGKPADDAGLV), reported free-base formula C62H98N16O22, molecular weight approximately 1419.5 g/mol, CAS 137525-51-0, PubChem CID 9941957. The sequence and the 1419 mass appear in the rodent tendon report itself (Staresinic et al., J Orthop Res 2003, PMID 14554208). The chain holds no cysteine and no methionine, so there is no disulfide to protect and no thioether to oxidize.
TB-500 has two identities in circulation, differing by roughly a factor of five in mass. The acetylated heptapeptide Ac-LKKTETQ is PubChem CID 62707662, C38H68N10O14, approximately 889.0 g/mol, CAS 885340-08-9. Full-length thymosin beta-4 is a separate record: CID 16132341, C212H350N56O78S, approximately 4963 g/mol, CAS 77591-33-4, and those are the values printed in the Compound Information panel of the Disguised Alpha TB-500 listing. Both are commonly supplied as acetate or trifluoroacetate salts, so confirm species, salt form, net content and molecular weight against the batch certificate before any molarity calculation.
Side by Side
| Attribute | BPC-157 | TB-500 |
|---|---|---|
| Compound class | Synthetic pentadecapeptide, 15 residues | Acetylated heptapeptide fragment of thymosin beta-4; name also used for the full 43-residue protein |
| Origin | Partial sequence of a protein described in human gastric juice | Residues 17 to 23 of thymosin beta-4, N-terminus acetylated |
| Identity data | C62H98N16O22, approximately 1419.5 g/mol, CAS 137525-51-0 | Fragment: C38H68N10O14, 889.0 g/mol, CAS 885340-08-9. Full protein: C212H350N56O78S, 4963 g/mol, CAS 77591-33-4 |
| Mechanism as reported | FAK and paxillin phosphorylation with fibroblast migration; VEGFR2-Akt-eNOS signaling | Actin binding and sequestration, cell migration; PINCH and integrin-linked kinase complex activating Akt |
| Study models cited | Rat Achilles transection, tendon explants and fibroblasts, chick chorioallantoic membrane, human endothelial cells, rat hind-limb ischemia | Rat dermal wounds, keratinocyte assay, mouse cardiomyocytes and coronary ligation, rat Achilles transection, equine administration |
| Human clinical evidence | Three pilot studies in review, no controlled trials | None retrieved for the fragment |
| Supplied form | Lyophilized powder, single vial, also in a blend with TB-500 | Lyophilized powder, single vial, also in a blend with BPC-157 |
Research Context: BPC-157
Rodent tendon work is the anchor. In rat Achilles transection, BPC-157 was reported to improve load to failure, modulus of elasticity, functional index scores and histological organization against saline controls, and in parallel cell work it reversed the growth-inhibiting effect of 4-hydroxynonenal on cultured tendocytes (Staresinic et al., J Orthop Res 2003, PMID 14554208). Models: rat and rat tendon cells.
A mechanism study in rat tendon explants and cultured tendon fibroblasts reported accelerated explant outgrowth, higher cell survival under hydrogen peroxide stress, dose-dependent transwell migration, F-actin formation, and dose-dependent phosphorylation of focal adhesion kinase and paxillin with total protein unchanged (Chang et al., J Appl Physiol 2011, PMID 21030672). Models: ex-vivo explants and cell culture.
A vascular study reported increased vessel density in the chick chorioallantoic membrane and endothelial tube formation assays, faster blood-flow recovery in rat hind-limb ischemia, and increased expression and internalization of VEGFR2 with VEGFR2-Akt-eNOS activation in human endothelial cells (Hsieh et al., J Mol Med 2017, PMID 27847966). Models: chick embryo assay, rat, human cell culture.
Two 2025 reviews size up that evidence base. A systematic review included 36 studies, 35 preclinical and one clinical, reporting a half-life under 30 minutes and no clinical safety data (Vasireddi et al., HSS J 2025, PMID 40756949). A narrative review counted three human pilot studies and called the compound investigational (McGuire et al., Curr Rev Musculoskelet Med 2025, PMID 40789979).
Research Context: TB-500 and Thymosin Beta-4
The dermal literature belongs to the parent protein. In a rat full-thickness wound model, thymosin beta-4 was reported to increase re-epithelialization at days 4 and 7, increase wound contraction, and raise collagen deposition and angiogenesis, with keratinocyte migration stimulated two to three fold in a Boyden chamber assay (Malinda et al., J Invest Dermatol 1999, PMID 10469335). Models: rat and cell assay.
The cardiac work describes a separate pathway: thymosin beta-4 promoted myocardial and endothelial cell migration in the embryonic heart, improved cardiomyocyte survival in culture, and formed a complex with PINCH and integrin-linked kinase that activates Akt, with both upregulated after coronary artery ligation in mice (Bock-Marquette et al., Nature 2004, PMID 15565145). Models: mouse embryo, cell culture, mouse ligation.
Work on the fragment itself is mostly analytical: mass spectrometry identified Ac-LKKTETQ in a TB-500 preparation and confirmed it by independent synthesis (Esposito et al., Drug Test Anal 2012, PMID 22962027), and a method study detected it and its metabolites in equine urine and plasma after a single administration (Ho et al., J Chromatogr A 2012, PMID 23084823).
The only head-to-head experiment used four groups in one rat Achilles transection and repair model: control, BPC-157, TB-500 and the combination, given for four weeks. Load to failure was higher in both treated groups and significant for TB-500; Bonar scores were significantly lower in the TB-500 group and Movin scores in the TB-500 and combination groups. The combination added nothing over either alone, and the authors call the study exploratory (Bicer et al., Jt Dis Relat Surg 2026, PMID 42542926).
Choosing Between Them for a Research Question
Pick by endpoint. A design built on focal adhesion signaling, fibroblast migration or VEGFR2-dependent angiogenesis has direct precedent with BPC-157. A design built on actin dynamics, integrin-linked kinase and Akt, cardiomyocyte survival or epithelial migration has direct precedent with thymosin beta-4 and its fragment.
TB-500 carries one extra decision: which species the study is using. BPC-157 has one CAS number and one mass; a protocol naming only TB-500 is under-specified until the certificate is read. If a design needs both in one vial, the fixed blend supplies them, with the caveat that the head-to-head rodent study found no additive effect. Neither has controlled human efficacy data, so any comparison compares preclinical evidence bases.
Handling and Storage
Both ship lyophilized, and lyophilized is the stable state. Standard practice: keep the sealed vial cold and dark, bring it to room temperature before opening so moisture does not condense onto the cake, add diluent gently down the vial wall, and let the material dissolve instead of shaking it. The Disguised Alpha pages for both state minus 20 C for the powder as shipped and 2 to 8 C after reconstitution, protected from light, freeze-thaw cycles avoided.
In solution, treat both as time-limited: aliquot into single-use volumes, label each with the lot number, and record the certificate molecular weight used for molarity. Neither BPC-157 nor Ac-LKKTETQ contains cysteine, so disulfide scrambling is not a concern; aggregation driven by agitation, heat and concentration is the shared failure mode.
Questions Researchers Ask
Is TB-500 the same thing as thymosin beta-4?
Not necessarily. Published analysis of TB-500 preparations identified the acetylated 17 to 23 fragment near 889 g/mol (Esposito et al., Drug Test Anal 2012, PMID 22962027), while full thymosin beta-4 is a 43-residue protein near 4963 g/mol. The certificate decides which one a lot is.
Do the two act by the same mechanism?
Reported mechanisms differ: focal adhesion kinase, paxillin and VEGFR2-Akt-eNOS signaling for BPC-157, actin sequestration and an integrin-linked kinase complex for thymosin beta-4. Convergence downstream was raised as an untested hypothesis in the head-to-head rodent study (Bicer et al., Jt Dis Relat Surg 2026, PMID 42542926).
Has anyone compared them directly?
Once, in rats: the four-group Achilles study reported a significant biomechanical advantage in the TB-500 group at four weeks and no additive effect from the combination (Bicer et al., Jt Dis Relat Surg 2026, PMID 42542926).
What should be confirmed on the certificate?
Printed lot identity, the identified species and its molecular weight, HPLC purity against specification, measured net peptide content, and the salt or counterion.
BPC-157 and TB-500 are supplied strictly for laboratory and in-vitro research use. They are not for human consumption, veterinary use, or any diagnostic or therapeutic application. Nothing on this page is medical, dosing, or therapeutic advice.