BPC-157 and TB-500 are two different molecules with two different evidence bases: a 2025 systematic review of BPC-157 found 36 studies, 35 of them preclinical and one a retrospective series of 12 patients [1], while TB-500 is a seven-residue fragment of thymosin beta-4 whose only human study is a trial registered in 2026 that has not yet reported [2, 14]. As of 4 November 2026, FDA lists both substances among 503A bulk substance nominations that were placed in category 2 and later withdrawn, a draft HHS interim policy published on 30 October 2026 names both among six peptides for 503A enforcement discretion under ten conditions, and the WADA 2026 Prohibited List names BPC-157 under S0 and TB-500 under S2.3 [8, 12, 30].
A patient who asks about the pair is usually asking four things: what each molecule is, what the tendon, ligament and angiogenesis studies measured and in how many animals, which human trials exist, and how the two differ under US compounding and anti-doping rules. The sections below answer each in that order. ExaVeyra Sciences supplies licensed practices; every clinical decision described here belongs to the prescriber.
Regulatory status
Neither BPC-157 nor TB-500 is an FDA-approved drug, and as of 4 November 2026 FDA’s compounding page places both in the table of substances previously in category 2 of the interim policy whose nominations were withdrawn, which leaves each on no 503A list for any route [8, 10]. The Pharmacy Compounding Advisory Committee considered both on 23 July 2026 [9], and on 30 October 2026 HHS published a draft interim enforcement discretion policy under which it does not intend to act against 503A compounding of six peptides, BPC-157 and TB-500 among them, when ten conditions are met, a policy HHS describes as not binding and open for comment to 13 November 2026 [11, 30]. ExaVeyra offers BPC-157, TB-500 and other non-catalog peptides for IND-authorized clinical trials through our pharmacy partner, with the sponsor’s IND number, sponsor details and protocol confirmed before any supply; our pharmacy partner reads the interim policy’s conditions for any patient-specific prescription, and the practitioner decides any use.
Understanding the two molecules begins with their size and origin
BPC-157 is a 15-residue peptide, sequence GEPPPGKPADDAGLV, described by its originating group as a stable fragment of a gastric protein and studied for three decades mostly in rat models from one laboratory in Croatia [19, 7]. A 2026 pharmaceutics review reported that it has no approved formulation, no validated regimen and no completed phase 2 trial, and that a preclinical ADME study confirmed a plasma half-life under 30 minutes [7].
TB-500 is the N-acetylated seven-residue peptide LKKTETQ, residues 17 to 23 of thymosin beta-4, a 43-residue protein present in most mammalian cells [18, 24]. Philp and colleagues reported in 2003 that this actin-binding motif reproduced the angiogenic activity of the full protein at about 50 nM in endothelial migration and aortic arch sprouting assays, which is the experimental origin of the fragment [24].
The human studies often attributed to TB-500 used the full protein [2]. Tham and colleagues reviewed the literature to June 2026 and reported that TB-500 is frequently conflated with thymosin beta-4 despite the absence of validated biologic or clinical equivalence [2]. The evidence pages for BPC-157 and TB-500 on this site take each molecule on its own record.
Published tendon and ligament studies of BPC-157 are rat models from one program
Staresinic and colleagues reported in 2003 that rats with a transected Achilles tendon given BPC-157 intraperitoneally at three quantities showed higher load to failure, Young modulus and functional index scores than saline controls across days 1 to 14 [19]. Krivic and colleagues reported in 2006 that the same peptide improved functional index, load to failure and collagen organization after Achilles detachment from bone, assessed through day 21 [22].
Cerovecki and colleagues reported in 2010 that medial collateral ligament transection in rats, followed for 90 days, showed functional, biomechanical and histological improvement in intraperitoneal, oral and topical peptide arms compared with controls [21]. Chang and colleagues, an independent group, reported in 2011 that the peptide accelerated outgrowth from tendon explants and increased fibroblast migration and survival under oxidative stress, without a direct effect on proliferation [20].
The angiogenesis mechanism most often proposed comes from Hsieh and colleagues, who reported in 2017 increased vessel density in chick membrane and tube formation assays, faster blood-flow recovery in a rat hind-limb ischemia model, and increased VEGFR2 expression and internalization in human endothelial cells [23]. Vasireddi and colleagues summarized the field in 2025 as level IV and V evidence, with preclinical models reporting improved outcomes in muscle, tendon, ligament and bone [1].
Thymosin beta-4 carries the human trials, and the fragment carries one registration
Malinda and colleagues reported in 1999 that the full protein, applied topically or intraperitoneally to rat full-thickness wounds, raised reepithelialization 42 percent above saline controls at day 4 and up to 61 percent at day 7 [25]. Ruff and colleagues reported in 2010 a phase 1 randomized placebo-controlled study of intravenous synthetic thymosin beta-4 in four cohorts of ten healthy volunteers, with infrequent mild or moderate adverse events and no dose-limiting toxicity [26].
The ophthalmic program, RGN-259, produced the largest randomized datasets. Sosne and Ousler reported in 2015 a 72-subject double-masked phase 2 trial in which neither primary endpoint reached significance while several secondary endpoints favored the peptide and no adverse events were observed [27]; a nine-patient severe dry eye trial reported a 35.1 percent reduction in discomfort at day 56 [28]. Treadwell and colleagues reported that in two phase 2 ulcer trials the wounds that did heal closed about a month sooner in peptide groups [29].
None of those trials used the seven-residue fragment. The first registered human study of TB-500 itself, NCT07487363, is a phase 1 and 2 cardiovascular biomarker study planned for 80 participants that began recruiting in February 2026 [14]. For BPC-157, the registry held a single 2015 phase 1 record planned for 42 participants, status unknown, until three studies were registered in 2026: a phase 2 trial planned for 120 participants, a phase 1 trial planned for 30, and a completed single-arm oral supplement study of 40 [13].
A 2026 rat study examined the two peptides side by side and in combination
Biçer and colleagues reported in 2026 the only head-to-head comparison located: 32 male rats with Achilles transection and repair, randomized to control, BPC-157, TB-500 or both, eight per group, assessed at four weeks [5]. The study reported higher maximum load to failure in both peptide groups than in controls, reaching statistical significance only in the TB-500 group, and lower histopathology scores in the TB-500 and combination groups.
The same study reported that combined BPC-157 and TB-500 did not confer additional benefit compared with either agent alone [5]. That single exploratory finding, eight animals per arm, is the entire controlled evidence base for the combination that search engines call a stack, and the authors describe it as an exploratory rat model study of early repair [5].
Combined BPC-157 and TB-500 treatment did not confer additional benefits compared to either agent alone, the study reported, in an exploratory four-week rat model of eight animals per group.
Several questions remain open in the published evidence
A practice fields the comparison more easily when the gaps are stated alongside the studies. The points below set out what the published evidence does not yet show for either molecule.
- No controlled human trial of BPC-157 has been published; the one clinical study in the 2025 systematic review was a retrospective series in which 7 of 12 patients reported relief after intraarticular use, without validated outcome measures [1, 2].
- No human trial of the TB-500 fragment has reported results; the thymosin beta-4 trials used the full 43-residue protein by ophthalmic, topical or intravenous routes [2, 14, 27].
- No human tendon or ligament outcome exists for either molecule; Tewari and colleagues reported in 2026 that 67 percent of publications on six marketed peptides were animal studies and that human data were a handful of weakly controlled investigations [6].
- No clinical safety dataset exists for BPC-157; Vasireddi and colleagues found no clinical safety data, and Mateescu and colleagues reported the human pharmacokinetic profile as critically undercharacterized [1, 7].
- No validated regimen, route or formulation exists for either peptide, and a half-life under 30 minutes for BPC-157 sits unexplained beside effects reported to last hours to days in animals [7].
- Product identity is uncertain outside a pharmacy: Janvier and colleagues reported purity between 5 and 75 percent for cysteine-containing peptides and arsenic and lead above ICH parenteral limits in falsified peptide products bought online [16].
The 503A category record and the WADA list separate legal status from sport status
FDA’s page on bulk substances that may present significant safety risks, content current as of 22 April 2026 and read on 4 November 2026, lists BPC-157 and thymosin beta-4 fragment (LKKTETQ), also known as TB-500, in its table of substances previously in category 2 whose nominations were withdrawn [8]. For BPC-157 the agency wrote that it had identified no, or only limited, safety-related information for the proposed routes; for the fragment it wrote that it had not identified any human exposure data [8].
A withdrawn nomination leaves a substance on no 503A list, and FDA’s bulks page states that a 503A compounder may use a bulk substance only under a USP or NF monograph, as a component of an approved drug, or from the 503A bulks list set by rulemaking [10]. The advisory committee discussed BPC-157 and TB-500 on 23 July 2026, and the meeting page states ulcerative colitis and wound healing as the uses FDA evaluated; the page posts no vote summary, and the HHS policy document records that CDER recommended against listing each peptide while the committee voted in favor, advice that leaves the decision with FDA [9, 30].
HHS then published on 30 October 2026 a notice of availability for a draft interim enforcement discretion policy, 91 FR 68526, with comments open to 13 November 2026 [11]. Appendix A names six peptides, BPC-157, epitalon, KPV, MOTS-c, semax and TB-500, and the policy applies to state-licensed pharmacies, federal facilities and licensed physicians compounding under 503A until FDA rulemaking decides each peptide’s place on the bulks list [30]. A covered peptide stays in FDA’s withdrawn-nominations table and off the codified 503A bulks list in the meantime [8, 30].
The ten conditions read as a documentation standard: bulk substance from an FDA-registered original manufacturer with a certificate of analysis meeting the appendix testing standard, a single active ingredient per product, reporting of products and serious adverse events to MedWatch and the states, a label stating the product is compounded and not for resale, a 510(k)-cleared syringe as the only delivery device, oral bioavailability documentation for any oral form, and a patient-specific prescription [30]. The route limits are specific to each peptide: subcutaneous, intramuscular, oral and topical dosage forms for BPC-157 acetate, and subcutaneous or intramuscular injectable forms for TB-500 acetate, with no intravenous route for either [30]. GHK-Cu, CJC-1295 and ipamorelin are absent from the list, and 503B outsourcing is not addressed [30].
Sport status is a separate question with a clearer answer. The WADA 2026 Prohibited List, in force 1 January 2026, names BPC-157 as an example under S0, non-approved substances prohibited at all times, and names thymosin-beta-4 and its derivatives, with TB-500 as the example, under S2.3, growth factors prohibited at all times [12]. Antidoping laboratories have published validated urine methods for both molecules [17, 18].
Labeling a vial for research does not change its status when it is sold for human use. In a 2023 warning letter the FDA stated that despite labeling for research purpose only and not for human consumption, the firm’s BPC-157 and TB-500 products were intended as drugs for human use because of the claims made for them, and listed both as unapproved new drugs [15].
A side-by-side table summarizes the record for each peptide
The table places the two molecules beside each other on structure, evidence, regulatory status and sport status, with the source for each cell. A practice can hand a patient the same comparison it reads itself.
| Attribute | BPC-157 | TB-500 (LKKTETQ) | Source |
|---|---|---|---|
| Structure | 15 residues, GEPPPGKPADDAGLV, gastric protein fragment | 7 residues, N-acetyl LKKTETQ, residues 17 to 23 of thymosin beta-4 | [18, 19, 24] |
| Animal tendon and ligament data | Rat Achilles transection, detachment and MCL series from one program; independent explant work | One 2026 rat Achilles study; the fragment’s own literature is small | [5, 19, 20, 21, 22] |
| Angiogenesis data | VEGFR2 activation in chick membrane, rat hind limb and human endothelial cells | Actin-binding motif reproduced full-protein activity at about 50 nM in vitro | [23, 24] |
| Published human trials | None controlled; one retrospective series of 12 patients | None for the fragment; full-protein trials of 9, 40, 72 and 72 participants | [1, 26, 27, 28, 29] |
| Registered studies, 5 Nov 2026 | Four records: 42 planned (2015, status unknown); 120 and 30 planned, and 40 in a completed single-arm oral supplement study (2026) | One record: 80 participants planned, phase 1 and 2, recruiting | [13, 14] |
| FDA 503A status | Category 2, nomination withdrawn; on no 503A list | Category 2, nomination withdrawn; on no 503A list | [8, 10] |
| PCAC | Discussed 23 July 2026; use FDA evaluated, per the meeting page: ulcerative colitis | Discussed 23 July 2026; use FDA evaluated, per the meeting page: wound healing | [9] |
| HHS interim policy, 30 Oct 2026 | Listed; subcutaneous, intramuscular, oral and topical forms under ten conditions | Listed; subcutaneous or intramuscular forms under ten conditions | [11, 30] |
| WADA 2026 list | S0 non-approved substances, named as an example | S2.3 growth factors, named as the thymosin-beta-4 example | [12] |
| Supply through ExaVeyra | IND-authorized clinical trials through our pharmacy partner | IND-authorized clinical trials through our pharmacy partner | Supplier position |
Patient conversations rest on the same documents a sponsor would need
When a patient asks about either peptide, the reviews written for orthopedic and sports medicine physicians converge on the same counsel: distinguish preclinical plausibility from clinical validation, raise product quality, and address the anti-doping rules for anyone who competes [2, 3, 4]. Mendias and Awan reported in 2026 that a gray market for these peptides operates largely outside regulatory oversight, with scarce human safety data [3].
For a practice, the route that exists today is the investigational one. ExaVeyra offers BPC-157, TB-500 and other non-catalog peptides for IND-authorized clinical trials through our pharmacy partner, with the sponsor’s IND number, sponsor details and protocol confirmed before any supply, and the clinic launch guide on adding 503A peptides explains how that documentation is assembled.
A verified account places the documentation within reach
A practice that wants to work with either peptide inside a trial starts with the sponsor’s IND number, the sponsor details and the protocol, and ExaVeyra confirms those before any supply through our pharmacy partner. The catalog peptides and hormone preparations that are compounded by our 503A pharmacy partner against a patient-specific prescription sit behind the same verified account.
Anyone may apply or ask the scientific team a question without an NPI, and NPI verification, which takes 1 to 3 business days, gives access to the practitioner portal, product documentation and pricing. One trial of BPC-157 and one of TB-500 opened for recruitment in 2026, a second BPC-157 trial is registered to start in 2027, and practices that keep their documentation in order will be ready to read those results as they arrive.
Aviso Educativo: This article is for educational purposes only and does not constitute medical or legal advice. It does not identify any material, compound, device setting or protocol as safe, effective or appropriate for any patient, and it is not intended to diagnose, treat, cure, or prevent any disease. Questions about a treatment belong with the reader’s own licensed provider. Exosome material is supplied for topical aesthetic use by licensed practitioners. No exosome product is FDA-approved for any use, and ExaVeyra Sciences makes no statement about administration, route, or outcome. Compounded medications are not FDA-approved. They are prepared by a 503A compounding pharmacy licensed by the Texas State Board of Pharmacy for an individual patient against that patient’s prescription, and are available to NPI-verified licensed practitioners only, in the states where the pharmacy is licensed. Product, device and brand names mentioned are trademarks of their respective owners and are used only to identify the products discussed. Their mention is not an endorsement, and those owners have not reviewed or endorsed this article. ExaVeyra Sciences is a supplier and takes no part in any diagnosis, treatment decision, or plan of care. Findings described are attributed to the peer-reviewed literature, trial registries and agencies cited. The content of these guides is provided for general informational purposes only. It does not constitute legal, medical, or regulatory advice, and does not establish that any particular product or practice is compliant. Regulatory requirements vary by state and depend on the circumstances of each practice. Each practitioner should consult their own legal counsel and the applicable state licensing boards before acting on anything stated here.
Referencias
- 1.Vasireddi N, Hahamyan H, Salata MJ, Karns M, Calcei JG, Voos JE, et al. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS J. 2025;21(4):485-495. PMID 40756949. doi:10.1177/15563316251355551Systematic review of PubMed, Cochrane and Embase to June 2024; 36 studies included, 35 preclinical and 1 clinical. Carries in this article: the animal literature reported improved functional, structural and biomechanical outcomes in muscle, tendon, ligament and bone models; the single human study was a retrospective series in which 7 of 12 patients reported relief after intraarticular use; no clinical safety data were found. Disclosure: several authors declare industry relationships (Stryker, Smith and Nephew, Arthrex) in the PubMed record.
- 2.Tham A, Hodgkins CW, Kennedy JG. Investigational Peptides in Orthopaedic Practice: Evidence, Safety, and Patient Counseling for BPC-157, Thymosin Beta-4, and TB-500. J Am Acad Orthop Surg. 2026. Published online ahead of print. PMID 42937313. doi:10.5435/JAAOS-D-26-00049Narrative review of PubMed, Embase and Scopus to June 2026 with primary regulatory and antidoping sources. Carries in this article: BPC-157 has the largest body of direct musculoskeletal preclinical evidence while human evidence is one small uncontrolled case series; thymosin beta-4 has broader human experience in ophthalmic, dermatologic and cardiovascular settings; TB-500 is a distinct seven-residue fragment frequently conflated with the full protein without validated equivalence. Disclosure: none stated in the PubMed record.
- 3.Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026;56(8):1921-1935. PMID 41966639. doi:10.1007/s40279-026-02437-0Narrative review of approved and unapproved peptides marketed direct to patients, including BPC-157, thymosin beta-4 and TB-500. Carries in this article: the authors describe favorable tissue outcomes in animal models alongside scarce human safety data and a gray market operating outside regulatory oversight. Disclosure: one author reports consulting fees from Arthrex unrelated to the topic.
- 4.Villegas Meza AD, Nocek M, Mitchell BC, Lizarraga M, DeFoor MT, Ruzbarsky JJ, et al. Injectable Peptides in Sports Medicine: A Structured Narrative Review of Evidence, Safety, and Antidoping Implications. JBJS Rev. 2026;14(5). PMID 42160466. doi:10.2106/JBJS.RVW.26.00027Structured narrative review of human and translational studies published January 2020 to August 2025 across PubMed, Embase and Web of Science. Carries in this article: BPC-157 and thymosin derivatives remain investigational with uncertain safety profiles, product quality concerns and widespread antidoping restrictions. Funding: Steadman Philippon Research Institute listed in the PubMed record.
- 5.Biçer O, Adanir O, Güleryüz Y, Balci EC, Dinçel YM, Yenigün MY, et al. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg. 2026;37(3):822-837. PMID 42542926. doi:10.52312/jdrs.2026.2951Randomized four-arm rat study; 32 male Sprague-Dawley rats, eight per group (control, BPC-157, TB-500, both), four weeks after Achilles transection and repair. Carries in this article: the study reported higher load to failure in both peptide groups, statistically significant only for TB-500, and that the combination conferred no additional benefit over either agent alone. Disclosure: none stated in the PubMed record.
- 6.Tewari K, Liu TP, Im C, Hamad C, Petrigliano F, Cheung EC, et al. Peptide Supplements and Their Therapeutic Applications in Sports Medicine. Am J Sports Med. 2026. Published online ahead of print. PMID 42578445. doi:10.1177/03635465261464420PRISMA scoping review of six peptides (BPC-157, thymosin beta-4 or TB-500, CJC-1295, MK-677, ipamorelin and GHK-Cu) across musculoskeletal tissues. Carries in this article: 67 percent of identified publications used preclinical animal models, human studies were a handful with weak controls, and the authors concluded the claimed benefits remain unsubstantiated by human trials. Disclosure: not stated in the PubMed record.
- 7.Mateescu DM, Gavrilescu DM, Constantinescu FE, Oancea C, Ilie AC, Folescu R, et al. BPC-157 as an Investigational Peptide Therapeutic: Biopharmaceutical Challenges, Formulation Strategies, and Translational Development Barriers. Pharmaceutics. 2026;18(5):625. PMID 42198317. doi:10.3390/pharmaceutics18050625Narrative review of PubMed, Embase and Cochrane to April 2026 with patent and regulatory agency searches. Carries in this article: no approved formulation, no validated regimen and no completed phase 2 trial exist for BPC-157, and a preclinical ADME study confirmed a plasma half-life under 30 minutes. Funding: a university in Romania; the authors declare no conflicts.
- 8.U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (category 2 of the interim policies, with the table of substances nominated but withdrawn). Content current as of 04/22/2026; verified 4 November 2026. https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risksAgency compounding page (CDER). Carries in this article: BPC-157 and thymosin beta-4 fragment (LKKTETQ), also known as TB-500, both sit in the table of substances previously in category 2 whose nominations were withdrawn, with the agency rationale for each quoted in the body; the page also lists CJC-1295 and GHK-Cu for injectable routes in the same table and ipamorelin acetate in both tables.
- 9.U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee (agenda, briefing documents for BPC-157 and TB-500, FDA presentations). Content current as of 08/06/2026; verified 4 November 2026. https://www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-compounding-advisory-committee-07232026Agency advisory committee page. Carries in this article: the committee discussed BPC-157 (free base and acetate) and TB-500 (free base and acetate) on 23 July 2026 for possible inclusion on the 503A bulks list, with ulcerative colitis the use evaluated for BPC-157 and wound healing the use evaluated for TB-500; as read on 4 November 2026 the page posts briefing documents and presentations and no vote summary or minutes.
- 10.U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. Content current as of 05/14/2026; verified 4 November 2026. https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-actAgency compounding page (CDER). Carries in this article: the three routes by which a bulk substance may be used under 503A (USP or NF monograph, component of an approved drug, or the 503A bulks list), the definitions of categories 1, 2 and 3 of the interim policy, and the statement that only notice-and-comment rulemaking places a substance on the list.
- 11.U.S. Department of Health and Human Services, Office of the Secretary. Enforcement Discretion Policy Regarding 503A Compounding Using Certain Peptide Bulk Drug Substances; notice of availability. Federal Register. 2026;91:68526-68527 (FR Doc. 2026-22192, Docket HHS-OASH-2026-0496), published 30 October 2026, comments to 13 November 2026; verified 4 November 2026 on govinfo.gov and the Federal Register API. https://www.federalregister.gov/documents/2026/10/30/2026-22192/enforcement-discretion-policy-regarding-503a-compounding-using-certain-peptide-bulk-drug-substancesFederal Register notice of availability of a draft interim policy, with a two-week comment window. Carries in this article: HHS stated it does not intend to take enforcement action against a state-licensed pharmacy, federal facility or licensed physician compounding under 503A with a peptide bulk substance listed in the policy appendix while rulemaking proceeds, that the draft establishes no rights and is not binding on HHS or the public, and that FDA rulemaking may later propose adding some or all of those peptides to the 503A bulks list.
- 12.World Anti-Doping Agency. The 2026 Prohibited List, World Anti-Doping Code International Standard, in force 1 January 2026 (S0 Non-approved substances; S2.3 Growth factors and growth factor modulators). PDF read on wada-ama.org, verified 4 November 2026. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdfInternational standard, English text. Carries in this article: S0 prohibits at all times any pharmacological substance with no current approval by a governmental health authority for human use and names BPC-157 as an example; S2.3 names thymosin-beta-4 and its derivatives, with TB-500 given as the example, among prohibited growth factors.
- 13.ClinicalTrials.gov. Registered studies returned for the term BPC-157 on 5 November 2026: NCT02637284 (PCO-02 safety and pharmacokinetics, phase 1, 42 participants estimated, started October 2015, status unknown); NCT07437547 (acute hamstring strain, phase 2, 120 participants estimated, recruiting, started February 2026); NCT07803250 (recovery after rotator cuff repair, phase 1, 30 participants estimated, not yet recruiting, estimated start January 2027); NCT07752381 (single-arm oral supplement study, 40 participants, completed, first posted 7 August 2026). https://clinicaltrials.gov/search?term=BPC-157Registry records read through the ClinicalTrials.gov v2 API. Carries in this article: for more than a decade the only registered human study of BPC-157 was a 2015 phase 1 record whose status is unknown, and three further studies were registered in 2026, which is the route by which human evidence for the peptide would arrive.
- 14.ClinicalTrials.gov. NCT07487363, TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD; phase 1 and 2, 80 participants estimated, recruiting, started February 2026; record read 4 November 2026. https://clinicaltrials.gov/study/NCT07487363Registry record. Carries in this article: the first registered human trial of the seven-residue fragment itself, as distinct from the full thymosin beta-4 protein studied in the RGN-259 and intravenous programs.
- 15.U.S. Food and Drug Administration, Center for Drug Evaluation and Research. Warning Letter to Warrior Labz SARMS (reference 655280), issued 12 June 2023, posted 20 June 2023; verified 4 November 2026. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/warrior-labz-sarms-655280-06122023Agency enforcement letter. Carries in this article: the agency stated that despite labeling for research purpose only and not for human consumption, the firm’s BPC-157 and TB-500 products were intended as drugs for human use because of the claims made for them, and listed both among unapproved new drugs.
- 16.Janvier S, Cheyns K, Canfyn M, Goscinny S, De Spiegeleer B, Vanhee C, et al. Impurity profiling of the most frequently encountered falsified polypeptide drugs on the Belgian market. Talanta. 2018;188:795-807. PMID 30029448. doi:10.1016/j.talanta.2018.06.023Laboratory analysis of the ten most frequently encountered falsified peptide products bought from three suspected illegal internet pharmacies. Carries in this article: the study reported high variation in content per unit, purity between 5 and 75 percent for cysteine-containing peptides, and arsenic and lead at up to ten times the ICH limit for parenteral drugs. Disclosure: Belgian public health institute authors.
- 17.Cox HD, Miller GD, Eichner D. Detection and in vitro metabolism of the confiscated peptides BPC 157 and MGF R23H. Drug Test Anal. 2017;9(10):1490-1498. PMID 28035768. doi:10.1002/dta.2152Analytical chemistry study from a WADA-accredited laboratory on peptides identified in confiscated vials. Carries in this article: BPC 157 forms a stable metabolite detectable in urine, the validated method has a limit of detection of 0.1 ng/mL, and the peptide was stable in urine for at least four days, which is the basis for antidoping detection.
- 18.Ho EN, Kwok WH, Lau MY, Wong AS, Wan TS, Lam KK, et al. Doping control analysis of TB-500, a synthetic version of an active region of thymosin β₄, in equine urine and plasma by liquid chromatography-mass spectrometry. J Chromatogr A. 2012;1265:57-69. PMID 23084823. doi:10.1016/j.chroma.2012.09.043Equine doping-control method paper. Carries in this article: the description of TB-500 as a veterinary preparation whose key ingredient is the N-acetylated peptide LKKTETQ, residues 17 to 23 of thymosin beta-4, with a validated detection method for urine and plasma.
- 19.Staresinic M, Sebecic B, Patrlj L, Jadrijevic S, Suknaic S, Perovic D, et al. Gastric pentadecapeptide BPC 157 accelerates healing of transected rat Achilles tendon and in vitro stimulates tendocytes growth. J Orthop Res. 2003;21(6):976-83. PMID 14554208. doi:10.1016/S0736-0266(03)00110-4Controlled rat study of complete Achilles transection with assessment on days 1, 4, 7, 10 and 14, plus tendocyte culture. Carries in this article: the study reported higher load to failure, Young modulus and Achilles functional index in peptide groups than in saline controls, at three quantities given intraperitoneally. Disclosure: the authors’ group holds the peptide research program.
- 20.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(3):774-80. PMID 21030672. doi:10.1152/japplphysiol.00945.2010In vitro study of rat Achilles tendon explants and cultured tendon fibroblasts by an independent group in Taiwan. Carries in this article: the study reported accelerated outgrowth from explants, no direct effect on proliferation, improved survival under oxidative stress and concentration-dependent migration and spreading, with FAK-paxillin phosphorylation proposed as the mechanism.
- 21.Cerovecki T, Bojanic I, Brcic L, Radic B, Vukoja I, Seiwerth S, et al. Pentadecapeptide BPC 157 (PL 14736) improves ligament healing in the rat. J Orthop Res. 2010;28(9):1155-61. PMID 20225319. doi:10.1002/jor.21107Controlled rat study of medial collateral ligament transection followed for 90 days with intraperitoneal, oral and topical peptide arms. Carries in this article: the study reported functional, biomechanical and histological improvement in ligament groups compared with controls, the ligament counterpart of the tendon series.
- 22.Krivic A, Anic T, Seiwerth S, Huljev D, Sikiric P. Achilles detachment in rat and stable gastric pentadecapeptide BPC 157: Promoted tendon-to-bone healing and opposed corticosteroid aggravation. J Orthop Res. 2006;24(5):982-9. PMID 16583442. doi:10.1002/jor.20096Controlled rat study of Achilles detachment from the calcaneus assessed at days 1 to 21, with a methylprednisolone comparison arm. Carries in this article: the study reported improved Achilles functional index, load to failure and collagen organization at the tendon-to-bone junction in peptide groups.
- 23.Hsieh MJ, Liu HT, Wang CN, Huang HY, Lin Y, Ko YS, et al. Therapeutic potential of pro-angiogenic BPC157 is associated with VEGFR2 activation and up-regulation. J Mol Med (Berl). 2017;95(3):323-333. PMID 27847966. doi:10.1007/s00109-016-1488-yMechanistic study using the chick chorioallantoic membrane assay, endothelial tube formation, a rat hind-limb ischemia model and human endothelial cells. Carries in this article: the study reported increased vessel density, faster blood-flow recovery and increased VEGFR2 expression and internalization, the angiogenesis mechanism most often proposed for BPC-157.
- 24.Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK. The actin binding site on thymosin beta4 promotes angiogenesis. FASEB J. 2003;17(14):2103-5. PMID 14500546. doi:10.1096/fj.03-0121fjeIn vitro and ex vivo study using natural thymosin beta-4, proteolytic fragments and synthetic peptides in endothelial migration and chick aortic arch sprouting assays. Carries in this article: the seven-residue actin-binding motif showed near-identical angiogenic activity to the full 43-residue protein at about 50 nM, the experimental origin of the LKKTETQ fragment later sold as TB-500.
- 25.Malinda KM, Sidhu GS, Mani H, Banaudha K, Maheshwari RK, Goldstein AL, et al. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-8. PMID 10469335. doi:10.1046/j.1523-1747.1999.00708.xControlled rat full-thickness wound study with topical and intraperitoneal arms and a keratinocyte migration assay. Carries in this article: the study reported reepithelialization 42 percent above saline controls at day 4 and up to 61 percent at day 7, with increased collagen deposition and angiogenesis, the dermal evidence for the full protein.
- 26.Ruff D, Crockford D, Girardi G, Zhang Y. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223-9. PMID 20536472. doi:10.1111/j.1749-6632.2010.05474.xPhase 1 randomized placebo-controlled study; four cohorts of ten healthy subjects, single intravenous exposure then 14 daily exposures across four ascending quantities. Carries in this article: adverse events were infrequent and mild or moderate, with no dose-limiting toxicity or serious adverse event, and pharmacokinetics were dose proportional. Sponsor: the developer of synthetic thymosin beta-4.
- 27.Sosne G, Ousler GW. Thymosin beta 4 ophthalmic solution for dry eye: a randomized, placebo-controlled, Phase II clinical trial conducted using the controlled adverse environment (CAE™) model. Clin Ophthalmol. 2015;9:877-84. PMID 26056426. doi:10.2147/OPTH.S80954Single-center double-masked phase 2 trial; 72 subjects randomized 1:1 to 0.1 percent thymosin beta-4 or placebo for 28 days. Carries in this article: neither primary endpoint reached significance, several secondary endpoints favored the peptide, and no adverse events were observed, the largest published randomized human dataset for the full protein at the time.
- 28.Sosne G, Dunn SP, Kim C. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. Cornea. 2015;34(5):491-6. PMID 25826322. doi:10.1097/ICO.0000000000000379Multicenter double-masked placebo-controlled 56-day phase 2 trial in nine patients with severe dry eye at two US sites. Carries in this article: the study reported a 35.1 percent reduction in ocular discomfort and a 59.1 percent reduction in corneal staining in the peptide group at day 56, from 12 eyes against 6 control eyes, an example of the small size of the early RGN-259 trials.
- 29.Treadwell T, Kleinman HK, Crockford D, Hardy MA, Guarnera GT, Goldstein AL. The regenerative peptide thymosin β4 accelerates the rate of dermal healing in preclinical animal models and in patients. Ann N Y Acad Sci. 2012;1270:37-44. PMID 23050815. doi:10.1111/j.1749-6632.2012.06717.xNarrative summary of the thymosin beta-4 dermal program by its developers, covering animal models and two phase 2 trials in venous stasis and pressure ulcers (72 patients each on the registry). Carries in this article: the authors reported that wounds that did heal closed about a month sooner in peptide groups, with no efficacy claim for the fragment. Disclosure: authors affiliated with the sponsor.
- 30.U.S. Department of Health and Human Services. HHS Enforcement Discretion Policy Regarding 503A Compounding Using Certain Peptide Bulk Drug Substances, with Appendix A (interim access list) and Appendix B (peptide identities, route limits and testing standard). 16 pages; read on hhs.gov 4 November 2026. https://www.hhs.gov/sites/default/files/hhs-503a-peptide-enforcement-discretion-policy-appendix-b.pdfDraft interim policy document. Carries in this article: Appendix A lists six peptides (BPC-157, epitalon, KPV, MOTS-c, semax and TB-500); ten conditions apply, including a bulk substance from an FDA-registered manufacturer with a certificate of analysis meeting the appendix testing standard, a single active ingredient per product, MedWatch and state reporting, the label statement that the product is compounded and not for resale, a 510(k)-cleared syringe as the only delivery device, oral bioavailability documentation for any oral form, and a patient-specific prescription; the route limits read subcutaneous, intramuscular, oral and topical for BPC-157 acetate and subcutaneous or intramuscular for TB-500 acetate; the document records that CDER recommended against listing each peptide and the advisory committee voted in favor, and that neither the category 2 placement in September 2023 nor its removal on 22 April 2026 changed status under section 503A.