TB-500 FDA Approval Status 2026

TB-500 FDA Approval Status 2026. Is TB-500 FDA approved in 2026? Review TB-500 regulatory status, WADA and USADA warnings, and thymosin beta-4 research. RESEARCH CONTEXT NOTICE: This article discusses compounds available for laboratory and research use only. All efficacy data referenced comes from published clinical trials and is provided for educational purposes. These products are not intended for human consumption. PeptideStack does not provide medical advice. Key Takeaways TB-500 is NOT FDA approved — No regulatory approval exists for TB-500 in any therapeutic indication Derived from Thymosin Beta-4: TB-500 is a synthetic fragment of the naturally occurring 43-amino-acid protein Thymosin Beta-4 (Tβ4) No active FDA clinical trials: There are no current IND applications or FDA-registered trials for TB-500 itself Published preclinical research exists: Thymosin Beta-4 has peer-reviewed studies on wound healing, actin regulation, and cardiac repair PCAC vote, July 23, 2026: The FDA's Pharmacy Compounding Advisory Committee voted 8-6 with one abstention to recommend TB-500 free base and TB-500 acetate for the 503A Bulks List — a compounding recommendation, not an approval WADA Prohibited List: TB-500 is classified under S2 (Peptide Hormones, Growth Factors) on the World Anti-Doping Agency banned substance list Research-grade availability: TB-500 is available for laboratory and investigational use only What Is TB-500? TB-500 is a synthetic peptide corresponding to the active region (amino acids 17-23) of Thymosin Beta-4 (Tβ4), a naturally occurring protein found in virtually all human and animal cells. Thymosin Beta-4 was first isolated from the thymus gland in the 1960s by Allan Goldstein's laboratory at the George Washington University School of Medicine. For chart-forward research protocol context, see the tb-500 dosage guide, including loading-versus-maintenance conventions and 5mg/10mg vial reconstitution math. For TB-500 thymosin beta-4 FDA approval status searches, the answer is straightforward: TB-500 itself is not FDA approved, and the thymosin beta-4 research literature does not create an approved TB-500 drug. Related queries such as TB-500 legal status FDA approval 2026 and FDA TB-500 approval should be treated as regulatory-status questions, not evidence of approval. The TB 500 peptide is used exclusively in research settings to study the biological activities attributed to the parent Thymosin Beta-4 protein, particularly its role in actin regulation, cell migration, and tissue repair processes — the same regenerative, anti-inflammatory activity profile that places it on many a list of anti-inflammatory peptides researchers track. Property Detail Full Name Thymosin Beta-4 active fragment (TB-500) Amino Acids 43 (full Tβ4 sequence) Active Region LKKTETQ (residues 17-23) Molecular Weight ~4,963 Da (full Tβ4) Origin Thymus gland protein, ubiquitous in nucleated cells CAS Number 77591-33-4 (Thymosin Beta-4) FDA Status Not approved WADA Status Prohibited (S2 category) Is TB-500 FDA Approved? No. TB-500 is not FDA approved. TB-500 has no FDA approval for any therapeutic indication as of September 2026. It has not completed the clinical trial pathway required for regulatory approval, and there are no active Investigational New Drug (IND) applications filed with the FDA for TB-500 specifically. This places TB-500 in the same regulatory category as other research peptides like Ipamorelin and BPC-157 — compounds with published preclinical research but no regulatory pathway to market. For the parallel 2026 advisory committee review covering BPC-157, see our BPC-157 FDA approval status 2026 breakdown. For a complete overview of which peptides DO have FDA approval, see our FDA Approved Peptides List 2026 . The distinction matters for researchers: FDA-approved peptides like tesamorelin (Egrifta) have completed Phase III trials and post-market surveillance. TB-500 research remains at the preclinical stage. The 503A Compounding Vote on TB-500 (July 2026) TB-500's regulatory picture gained its first concrete movement in 2026, when the FDA's Pharmacy Compounding Advisory Committee (PCAC) reviewed thymosin beta-4 fragment bulk drug substances at its July 23-24, 2026 meeting. On July 23, 2026 the committee voted 8-6, with one abstention , to recommend TB-500 free base and TB-500 acetate for inclusion on the Section 503A Bulks List, with wound healing as the use evaluated. The same session produced matching 8-6 votes for BPC-157 and KPV, and a 7-5 vote for MOTS-c. That is a compounding-eligibility recommendation, not a drug approval, and it does not take effect on its own. FDA initiates notice-and-comment rulemaking and issues a final determination before a substance formally joins the 503A Bulks List — a process that historically runs from several months to more than a year. Two points matter for anyone reading headlines about the vote: TB-500 is still not FDA approved. There is no approved indication, no new drug application, and no FDA-registered human clinical trial program for TB-500. Compounding eligibility is not consumer availability. A 503A listing would allow a licensed compounding pharmacy to prepare TB-500 against a valid prescription. Research-grade material sold for laboratory use remains a separate channel entirely. Why the Vote Was Close: FDA's Stated Concerns FDA's briefing material for the meeting is the clearest public statement of why TB-500 has never advanced, and it maps directly onto the questions researchers ask most often: FDA concern What the record shows No human safety studies FDA's review identified no human safety studies for TB-500 — zero drug-exposed participants, no pharmacokinetic data, and no immunogenicity or aggregation assessment. No human exposure data FDA has stated it has not identified human exposure data for drug products containing the thymosin beta-4 LKKTETQ fragment (residues 17-23). Evidence is preclinical only Published efficacy work uses the parent Thymosin Beta-4 protein in animal models, not synthetic TB-500 in humans. No pharmacopoeial standard No USP or National Formulary drug-substance monograph exists for TB-500, and it is not a component of any FDA-approved drug. None of those findings changed as a result of the July 2026 recommendation. What changed is that a majority of the advisory committee concluded the narrower statutory compounding criteria were met — a different question from safety and efficacy for approval. Peptides Still Under Review PCAC has indicated it will further consider additions including injectable GHK-Cu , Melanotan II , Dihexa acetate , Cathelicidin LL-37 and PEG-MGF at a future meeting. Epitalon and Semax were recommended on July 24, 2026, and Emideltide (DSIP) was the only substance the committee declined to recommend — so the 503A classification question continues to move into 2027. Thymosin Beta-4 vs TB-500: Understanding the Difference A common source of confusion in TB-500 research is the relationship between TB-500 and Thymosin Beta-4. They are related but not identical: Characteristic Thymosin Beta-4 (Tβ4) TB-500 Nature Naturally occurring protein Synthetic research peptide Sequence Full 43-amino-acid protein Contains the active LKKTETQ region Source Found in all nucleated cells Manufactured synthetically Clinical trials Some ophthalmic studies (RegeneRx) None registered with FDA Research focus Broad biological characterization Targeted tissue repair studies Most published research references Thymosin Beta-4 rather than TB-500 by name. When researchers cite "TB-500 research," they are typically referencing studies conducted on the parent Thymosin Beta-4 protein or its active fragment. Published Research on Thymosin Beta-4 While TB-500 clinical trials registered with the FDA do not exist, Thymosin Beta-4 has a meaningful body of published preclinical research. Here are the key studies: Study Year Focus Key Finding Malinda et al. ( J Invest Dermatol ) 1999 Wound healing Tβ4 accelerated wound closure in rodent models by promoting keratinocyte migration Philp et al. ( FASEB J ) 2004 Cardiac repair Tβ4 reduced scar size and improved cardiac function post-myocardial infarction in mice Sosne et al. ( Ann NY Acad Sci ) 2007 Corneal repair Tβ4 promoted corneal epithelial wound healing and reduced inflammation Bock-Marquette et al. ( Nature ) 2004 Cardiac survival Tβ4 activated Akt survival pathway in cardiomyocytes after ischemic injury Smart et al. ( Nature ) 2011 Cardiac progenitors Tβ4 priming reactivated adult epicardial progenitor cells for cardiac repair Important context: These studies were conducted using Thymosin Beta-4 protein in animal models. Results cannot be directly extrapolated to synthetic TB-500 in human applications. The preclinical evidence, while promising, has not progressed to FDA-registered clinical trials for TB-500, and PubMed searches for TB-500 regulatory warnings between 2015-2026 consistently return the same conclusion: no certificate of analysis exists in any FDA database for TB-500 as an approved drug product, and researchers working with this compound should rely on vendor-provided third-party COAs for verification. Mechanism of Action The biological activities attributed to TB-500 stem from Thymosin Beta-4's role as a major actin-sequestering protein. Understanding these mechanisms is central to TB-500 peptide research : Actin Regulation Thymosin Beta-4 is the primary intracellular G-actin (monomeric actin) sequestering protein. By binding G-actin in a 1:1 complex, it regulates the availability of actin monomers for polymerization into filamentous actin (F-actin). This controls: Cell structure: Actin filaments form the cytoskeleton that determines cell shape Cell motility: Actin polymerization drives cell migration toward injury sites Cytokinesis: Actin dynamics are essential for cell division Cell Migration and Wound Healing Published research demonstrates that Thymosin Beta-4 promotes cell migration through: Endothelial cell migration: Critical for angiogenesis (new blood vessel formation) Keratinocyte migration: Relevant to dermal wound closure (Malinda et al., 1999) Anti-inflammatory properties: Modulation of NF-κB signaling in inflammatory models Angiogenesis Multiple studies have demonstrated Thymosin Beta-4's role in promoting new blood vessel formation. This angiogenic activity is relevant to tissue repair, as adequate blood supply is essential for healing processes. This mechanism is complementary to — but distinct from — the angiogenic properties of BPC-157 , which operates through different vascular growth factor pathways. Clinical Trial Landscape The TB-500 clinical trial landscape requires careful distinction between TB-500 and Thymosin Beta-4: TB-500 Specifically There are no FDA-registered clinical trials for TB-500. No pharmaceutical company has filed an IND application for TB-500 as a therapeutic agent. All TB-500 use remains confined to preclinical research settings. Thymosin Beta-4 (Parent Protein) RegeneRx Biopharmaceuticals conducted ophthalmic clinical trials using Thymosin Beta-4 (under the name RGN-259) for dry eye syndrome and neurotrophic keratopathy. These trials represent the closest any Tβ4-related compound has come to therapeutic development, though the program has not resulted in FDA approval as of February 2026. This contrasts sharply with peptides that have completed the regulatory pathway. For example, tesamorelin received FDA approval in 2010 for HIV-associated lipodystrophy after completing Phase III trials — a process TB-500 has not even begun. WADA Prohibited Status The TB-500 WADA classification is an important regulatory consideration. TB-500 (and Thymosin Beta-4) is listed on the World Anti-Doping Agency's Prohibited List under: For the broader cross-agency picture, including FDA, TGA, WADA, and USADA language, continue with this TB-500 regulatory status guide and compare it with our TB-500 legal status breakdown. Category: S2 — Peptide Hormones, Growth Factors, Related Substances, and Mimetics Status: Prohibited at all times (in-competition and out-of-competition) Testing: Detectable via mass spectrometry-based anti-doping tests This prohibition applies regardless of the compound's FDA approval status. Many WADA-prohibited substances are not illegal to possess for research but are banned in competitive athletics. Athletes subject to WADA testing should be aware of this classification. For a comprehensive breakdown of TB-500's legal status across jurisdictions, including DEA scheduling and international law, see our Is TB-500 Legal? guide. The WADA prohibition reflects the compound's biological activity profile — its potential effects on tissue repair and recovery fall under the category of performance-enhancing substances that the agency monitors. Beyond the WADA ban, additional regulatory warnings for the thymosin beta-4 fragment exist across multiple agencies: USADA (the United States Anti-Doping Agency) lists TB-500 as a prohibited peptide for competing athletes, Australia's TGA has issued warnings against its use, and the EMA has not registered it for therapeutic use in Europe. The Drugs@FDA database contains no entry for TB-500, and the FDA has publicly noted that there is no human exposure data supporting its safety. FDA, TGA, WADA, and USADA Warnings For searches around thymosin beta-4 FDA TGA WADA USADA warnings , the regulatory picture is consistent across agencies: TB-500 is not an FDA-approved drug, Australia's TGA lists TB-500 among unapproved peptide products with safety, quality, labeling, and import concerns, and WADA/USADA treat thymosin beta-4 derivatives such as TB-500 as prohibited for tested athletes. These warnings do not mean TB-500 is a controlled substance; they mean it lacks drug approval, has unresolved safety questions, and is banned under anti-doping rules. For TB-500 regulatory warnings EMA PubMed 2015-2026 searches, published PubMed-indexed research during this period still centers on thymosin beta-4 biology, ophthalmic development programs, and detection/metabolism work rather than FDA-approved TB-500 human-use data. The EMA has not authorized TB-500 as a human medicine, and the FDA has stated it has not identified human exposure data for drug products containing the thymosin beta-4 LKKTETQ fragment. Despite continued social media hype around TB-500 in recovery and wellness circles, none of the major regulators have moved toward approval, and consumer availability remains limited to research-grade product outside FDA-approved drug channels. TB-500 vs BPC-157: Brief Comparison TB-500 and BPC-157 are frequently discussed together in tissue repair research contexts. While both are research peptides without FDA approval, they differ significantly in origin, mechanism, and research background: Property TB-500 BPC-157 Origin Thymosin Beta-4 (thymus) Body Protection Compound (gastric juice) Amino Acids 43 15 Primary Mechanism Actin regulation, cell migration Angiogenesis, nitric oxide modulation WADA Status Prohibited (S2) Not currently prohibited FDA Status Not approved Not approved For a comprehensive comparison of mechanisms, research backgrounds, and combination research rationale, see our detailed BPC-157 vs TB-500 research comparison . Frequently Asked Questions Is TB-500 FDA approved? No. TB-500 is not FDA approved for any therapeutic indication. There are no active IND applications or FDA-registered clinical trials for TB-500, and it remains a research-only compound available for laboratory and investigational use. The advisory committee's July 2026 recommendation concerns 503A compounding eligibility only. Is TB-500 legal to buy? The TB-500 legal status varies by jurisdiction, but in the United States, TB-500 is legal to purchase for research and laboratory purposes. It is not a DEA-scheduled controlled substance. However, it is prohibited by WADA for competitive athletes and is not approved for human consumption. What is the difference between TB-500 and Thymosin Beta-4? Thymosin Beta-4 is the naturally occurring 43-amino-acid protein found in virtually all human cells. TB-500 is a synthetic research peptide that contains the biologically active region (LKKTETQ, residues 17-23) of Thymosin Beta-4. Most published research uses Thymosin Beta-4 rather than TB-500 by name. Why is TB-500 banned by WADA? TB-500 is WADA banned under category S2 (Peptide Hormones, Growth Factors) because its biological activity profile — promoting cell migration, tissue repair, and recovery — falls under the definition of performance-enhancing substances. This prohibition applies at all times, both in-competition and out-of-competition. Is TB-500 the same as BPC-157? No. TB-500 and BPC-157 are distinct peptides with different origins, amino acid sequences, and mechanisms of action. TB-500 derives from Thymosin Beta-4 and works through actin regulation; BPC-157 derives from gastric juice protein and works through angiogenesis and nitric oxide pathways. See our BPC-157 vs TB-500 comparison for a full breakdown. What did the FDA advisory committee decide about TB-500? On July 23, 2026, the FDA's Pharmacy Compounding Advisory Committee voted 8-6 with one abstention to recommend TB-500 free base and TB-500 acetate for the Section 503A Bulks List, evaluating wound healing as the proposed use. The recommendation is advisory: FDA is not legally bound by it and must complete notice-and-comment rulemaking before any listing takes effect. The FDA's own briefing material for the meeting identified no human safety studies for TB-500. Does the 503A vote mean TB-500 is approved or legal to compound now? No on both counts. TB-500 remains unapproved, with no NDA and no FDA-registered human trials. Compounded TB-500 is not yet permitted under Section 503A either — that requires FDA to finish rulemaking and formally add the substance to the bulks list, after which a licensed 503A pharmacy could prepare it against a valid prescription. Research-grade TB-500 sold for laboratory use sits outside the compounding pathway entirely. What is the BPC-157 TB-500 FDA status 2026? Neither is FDA approved. The current BPC-157 TB-500 FDA approval status 2026 shows both compounds have no active clinical trials and no pending IND applications. Both were recommended by PCAC on July 23, 2026 for the 503A Bulks List (8-6 with one abstention each), which is a compounding step still awaiting FDA rulemaking, not approval. For the BPC-157 TB-500 regulatory status FDA WADA 2026, TB-500 is WADA-prohibited while BPC-157 is not currently on the WADA prohibited list — but both remain research-only compounds without FDA approval. Conclusion The TB-500 FDA approval status is clear: it is not FDA approved and it has no active drug-approval pathway. Unlike compounds such as tesamorelin , which completed Phase III clinical trials and received FDA approval, TB-500 remains entirely in the preclinical research domain. The one 2026 development is on the compounding side: PCAC voted 8-6 (one abstention) on July 23, 2026 to recommend TB-500 free base and acetate for the 503A Bulks List. That recommendation is non-binding, still requires FDA rulemaking, and does not change the approval status, the WADA prohibition, or the laboratory-only supply channel. For researchers, TB-500 offers: A well-characterized active fragment of Thymosin Beta-4 Published preclinical data on wound healing, cardiac repair, and cell migration Complementary mechanism to BPC-157 for combination research Availability for laboratory and investigational protocols For comprehensive information on which peptides have FDA approval, see our FDA Approved Peptides List 2026 guide. Want to know what peptides Joe Rogan has discussed, including TB-500? See our Joe Rogan Peptides breakdown with episode citations. Reconstitution math: Use our free Peptide Calculator to determine concentration, syringe units, and doses per vial for your research protocols. Curious about the cost difference between clinical and research-grade compounds? See our peptide therapy cost breakdown . References Goldstein AL, et al. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med . 2005;11(9):421-9. PubMed Crockford D, et al. Thymosin beta4: structure, function, and biological properties supporting current and future clinical applications. Ann N Y Acad Sci . 2010;1194:179-89. PubMed Malinda KM, et al. Thymosin beta 4 accelerates wound healing. J Invest Dermatol . 1999;113(3):364-8. PubMed Bock-Marquette I, et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature . 2004;432(7016):466-72. PubMed Sosne G, et al. Thymosin beta 4 promotes corneal wound healing and decreases inflammation in vivo following alkali injury. Exp Eye Res . 2002;74(2):293-9. PubMed World Anti-Doping Agency. WADA Prohibited List — S2 Peptide Hormones, Growth Factors, Related Substances and Mimetics. wada-ama.org U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee (TB-500 and BPC-157-related bulk drug substances). fda.gov Liang L. Peptides: US advisory committee recommends six for FDA "compounding list". BMJ . 2026;394:e100422. bmj.com Fu M, Ross JS, Nguyen N-TA, Ramachandran R. FDA Advisory Committee's Vote May Open A Drug-Compounding Back Door For Unapproved Peptides. Health Affairs Forefront . August 4, 2026. healthaffairs.org U.S. Food and Drug Administration. FDA-2025-N-6895 Public Docket — Nominations for 503A Compounding Bulk Drug Substances List. regulations.gov ClinicalTrials.gov. Thymosin Beta-4 / TB-500 research registry search. clinicaltrials.gov Related reading: The peptide FDA status hub covers the regulatory picture for TB-500, BPC-157, GHK-Cu, and 10 more compounds. PeptideStack page context: visitors can use the header navigation to reach the product catalog, blog, calculators, supplier pages, discount-code pages, contact page, legal policies, privacy policy, terms, and research disclaimer. 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