Peptide dossier, updated Oct 31, 2026
TB-500
A synthetic fragment of thymosin beta-4. FDA describes it as the 17–23 fragment (LKKTETQ). FDA found no human studies of it. Since Oct 30, HHS has said it will pause enforcement against some pharmacies that compound it. This page lays out what each source actually says.
Human studies
One entry on ClinicalTrials.gov for “TB-500” as of Oct 31, 2026. PubMed’s 16 results for TB-500 include no human study of the peptide.
| Registry | Study | Sponsor | Status | What the record says |
|---|---|---|---|---|
| NCT07487363 | Phase 1/2, randomized, double-blind, placebo-controlled: safety, tolerability and biomarkers in stable atherosclerotic cardiovascular disease | Hudson Biotech | Recruiting | Planned 80 participants, three sequential dose cohorts, one site in Shenzhen, China. Started Feb 5, 2026. Primary completion estimated Feb 2027. First posted Mar 23, 2026. No results posted. |
Flag. The record’s own summary begins: “This fictional study is an example of a ClinicalTrials.gov-style record.” Its description says it “models common ClinicalTrials.gov data elements.” We cannot tell whether this is a placeholder, an error or a deliberate posting. We did not find the same wording in the same sponsor’s BPC-157 hamstring record. Treat this study as unverified until the sponsor or the registry clarifies it.
Registry entries are written by the sponsors and are not reviewed for scientific merit. A registered study is not a result.
FDA review
Two FDA documents address TB-500: the safety-risk page (content current Apr 22, 2026) and a briefing document for the July advisory committee, dated May 15, 2026.
What the briefing document found
- FDA evaluated TB-500 (free base) and TB-500 acetate for the 503A bulks list. The nomination was withdrawn, so FDA reviewed both on its own initiative.
- The nominated product was a 3 mg/mL injectable powder for wound healing. The supporting wound-healing studies used the non-acetylated LKKTETQ peptide, not TB-500 itself.
- No clinical studies, pharmacokinetic data or case reports in humans, by any route.
- Pharmacokinetic data are limited to one subcutaneous study in horses and one intraperitoneal study in rats. No acute, repeat-dose, genotoxicity, reproductive or carcinogenicity studies were found.
- In a lab fibroblast scratch assay, TB-500 at 50 µg/mL did not significantly close wounds. A metabolite showed a small effect.
- No adverse event reports in FAERS. Two complaints involved a blended TB-500 and BPC-157 product and lacked safety assessments.
What FDA concluded
- It proposed not adding either form to the list, citing insufficient characterization, no documented compounding history, no evidence of effectiveness or human safety data, and immunogenicity risk.
- FDA called both substances poorly characterized: names that do not follow standard nomenclature, conflicting CAS numbers and formulas, and certificates of analysis missing identity, aggregate and endotoxin results.
- It found no pharmacies or outsourcing facilities reporting compounded TB-500 and no USP monograph.
- Its safety-risk page says compounded drugs containing the fragment may pose immunogenicity risk for certain routes, because of aggregation and peptide-related impurities.
Published research
PubMed returns 16 results for “TB-500” or “TB500.” Most are reviews of peptide therapies. Two are studies that test or measure TB-500, and one review addresses it directly.
Animal and lab studies
- Rat Achilles tendon, 2026. 32 rats, tendon cut and repaired, treated 4 weeks with BPC-157, TB-500 (60 µg/kg/day), or both. Maximum load to failure was higher with TB-500 than in controls (p < 0.05), and tendon scores were better with TB-500. BPC-157 alone did not reach significance on total scores, and the combination added no benefit over either alone. The authors call it exploratory and say the dose and duration need more work. Jt Dis Relat Surg PubMed
- Analytical method, 2024. A chemistry paper on measuring TB-500 and its metabolites in lab tests and in rats, with in-vitro wound-healing screening. J Chromatogr B PubMed
- Orthopaedic review, Oct 2026. A narrative review of BPC-157, thymosin beta-4 and TB-500 searched through June 2026. It calls TB-500 a distinct seven-amino-acid fragment that is often conflated with full-length thymosin beta-4, with no validated biologic or clinical equivalence. It finds no FDA-approved musculoskeletal indication for any of the three, quality concerns about identity, purity, concentration and sterility in marketed products, and concludes routine clinical use cannot currently be recommended. J Am Acad Orthop Surg PubMed
Read with care
- One rat study is not evidence of an effect in people. FDA found no human data.
- We read both papers’ abstracts, not their full text, funding or author disclosures.
- The 2024 analytical paper tests how to detect and measure the peptide. It does not test a treatment.
FDA warning letters
One public warning letter we have confirmed names TB-500. The list may not be complete.
| Date | Recipient | Type | What the letter says about TB-500 |
|---|---|---|---|
| Jun 12, 2023 | Warrior Labz | Online seller | Its website took orders for TB-500 and BPC-157 (injectable and nasal spray), alongside SARMs and other products. Issued by FDA’s drug center. |
This letter was found through a web search, not a full pull of FDA’s database. A letter states FDA’s position at the time, not a court finding.
Patents
Google Patents lists 9 results for “TB-500” together with “thymosin.” The bare term “TB-500” returns about 760 results, mostly unrelated products and model numbers. We did not read claims or check legal status. Titles are as Google Patents shows them, some shortened.
| Number | Title | Applicant | Priority | Published |
|---|---|---|---|---|
| CN118767114A | Application of TB500 in the preparation of drugs for preventing or treating ... | Guangdong Ocean University | Aug 30, 2023 | Oct 15, 2024 |
| KR20250096505A | Composition for tissue regeneration and wound healing containing thymosin beta- ... | Korea Institute of Science and Technology (as listed in the search) | Dec 19, 2023 | Jun 27, 2025 |
| US20250360156A1 US20260053928A1 | Synergistic combination of NAD+ and therapeutic peptides delivered via ... (two US applications) | Nicholas Jerome Andrews | Apr 22, 2024 | Nov 27, 2025 and Feb 26, 2026 |
| US12651660B1 | Apparatus and method for peptide stack determination | Ageless Medicine Systems | Dec 10, 2024 | Jun 9, 2026 |
| EP4722714A1 | Simultaneous analysis of food-borne doping substances using liquid ... (a testing method) | Korea Institute of Science and Technology (as listed in the search) | Oct 7, 2024 | Apr 8, 2026 |
The other three results were not read: a 2025 Chinese application from Tianjin Eye Hospital on a thymosin beta-4 hydrogel, a 2017 Japanese application from ModernaTX, and a 2015 US application from Boston Medical Center. A patent shows what an owner claims, not that a product works or is safe. Unlike BPC-157, we found no early compound patent family for TB-500.
SEC filings
EDGAR full-text search for “TB-500” from Jan 2024 to Oct 31, 2026 returns 5 filings from 3 filers. All three also appear on the BPC-157 dossier.
| Filer | Filing | What it says |
|---|---|---|
| Regenerative Medical Technology Group | 10-Q · 10-Q Aug 19 & Nov 19, 2025 | Describes a preloaded BPC-157 and TB-500 injectable pen as its current best seller. |
| Fifty 1 Labs | Reg A offering Aug 10, 2026 | Describes itself as a biotechnology company focused on peptide products, naming BPC-157 and TB-500. |
| BioScience Health Innovations | 10-K · 10-Q Mar 30 & May 11, 2026 | The 10-K mentions TB-500 once. It says at least nine of the company’s formulations contain TB-500 and other peptides and could become commercially viable if FDA moves about 14 Category 2 peptides back to Category 1. This is a plan that depends on FDA action, not a current product. We read only the 10-K for this; the 10-Q matched the search and was not read. |
What a company says in a filing is its own claim about its business. It is not a finding about TB-500.
Timeline
Newest first. Every entry links to the document it comes from.
- Government or registry record
- Journal
- Oct 30, 2026RegulatoryHHS publishes draft policy pausing enforcement on six compounded peptides, TB-500 among them
State-licensed pharmacies, federal facilities and licensed physicians would not face enforcement for compounding it, under conditions including a patient-specific prescription and quality testing. Not FDA approval. HHS says it may revisit the policy if a safety or quality problem arises.
- Oct 27, 2026LiteratureOrthopaedic surgeons’ review covers BPC-157, thymosin beta-4 and TB-500
J Am Acad Orthop Surg, online ahead of print. A narrative review searching through June 2026. It describes TB-500 as a distinct seven-amino-acid fragment often conflated with full-length thymosin beta-4, notes no FDA-approved musculoskeletal indication for any of the three agents and concerns about the identity, purity and sterility of marketed products, and concludes routine clinical use cannot currently be recommended.
- July 23–24, 2026RegulatoryFDA advisory committee recommends TB-500 for the compounding list
The committee recommended six of the seven peptides it reviewed; emideltide was the exception. The vote is nonbinding: compounding stays unlawful until FDA finishes rulemaking or Congress changes the law. No vote count was in the source we could read.
- July 23, 2026LiteratureRat study: TB-500 and BPC-157 after Achilles tendon repair
Published in Jt Dis Relat Surg. TB-500 improved maximum load to failure and tendon scores versus controls in 32 rats; the combination with BPC-157 added no benefit. Details above.
- May 15, 2026RegulatoryFDA staff brief the committee: it proposes not adding TB-500
FDA found no human data, no repeat-dose, genotoxicity or carcinogenicity studies, and called the substance poorly characterized. Details above.
- Apr 22, 2026RegulatoryFDA’s safety-risk page lists the TB-500 fragment
FDA says compounded drugs containing the fragment may pose immunogenicity risk for certain routes, because of aggregation and peptide-related impurities, and that it identified no human exposure data. The page showed content current as of Apr 22, 2026.
- Feb–Mar 2026TrialsA Phase 1/2 TB-500 study is registered, with a flag
Hudson Biotech’s study began Feb 5 and was first posted Mar 23, 2026. Its own summary calls it a fictional example. See the flag above.
- 2024LiteratureAnalytical paper on measuring TB-500 and its metabolites
A chemistry study of detection methods in lab tests and rats.
- June 12, 2023RegulatoryFDA warning letter to an online seller names TB-500
Warrior Labz sold TB-500 and BPC-157 products alongside SARMs. Details above.
- Jan 1, 2022Anti-dopingWADA’s 2022 Prohibited List names TB-500 in section S2
S2 covers peptide hormones, growth factors and related substances. Under growth factors, the list reads “Thymosin-β4 and its derivatives e.g. TB-500.” We checked the 2022 list only, not earlier or later editions.
Still not covered
Left off rather than guessed:
- Patents: claims and legal status of the five relevant filings were not read or checked, and the search covered only the terms “TB-500” with “thymosin.”
- Thymosin beta-4 itself: trials of the full-length protein are a different drug and are not counted here.
- Seller claims and independent lab reports: how it is marketed versus what testing finds. FDA flags quality concerns but we have not collected testing data.
- Unread items: full text of the rat study and the orthopaedic review, and the BioScience Health Innovations 10-Q.
- Warning letter completeness: one letter from a search, not a full pull of FDA’s database.
- Panel vote counts: not in the sources we could read.
- The registry flag: whether NCT07487363 is a real study.