TB-500 is a synthetic 43-amino-acid peptide corresponding to Thymosin Beta-4 (Tβ4) — one of the most discussed healing peptides alongside BPC-157, and the most common stack partner in the research peptide community. Zero completed human clinical trials exist for TB-500 as of March 2026. A Phase 2 trial on the parent protein Tβ4 was completed in 2009, but results were never published — a significant gap in the evidence base.
This article applies 7 verification checks to TB-500 using data from Peptigrity's independent lab tests, community reviews, and reviewed peptide shops. Peptigrity does not sell peptides or recommend vendors.
What Is TB-500 and Why Does Source Quality Matter?
TB-500 is a synthetic 43-amino-acid peptide corresponding to Thymosin Beta-4 (Tβ4) — an actin-binding protein studied for cell migration, angiogenesis, and tissue repair in preclinical models — with zero completed human clinical trials as of March 2026.
The compound was originally characterised by Dr. Allan Goldstein at George Washington University. Tβ4 is one of the most abundant intracellular proteins in mammalian cells, functioning as a primary regulator of actin polymerisation. The LKKTETQ amino acid sequence is considered the functional core responsible for cell migration and wound repair activity in preclinical models.
A critical distinction that most sources omit: the TB-500 sold by research vendors is a synthetic analog of endogenous Thymosin Beta-4. Most preclinical research is conducted on the full Tβ4 protein, not the synthetic version sold as TB-500. The assumption that TB-500 replicates all Tβ4 effects is an extrapolation, not a demonstrated equivalence. Preclinical mechanisms attributed to Tβ4 include G-actin sequestration (cytoskeletal remodelling), promotion of cell migration via the actin/G-actin cycle, angiogenesis through VEGF-related signalling, and anti-inflammatory effects through cytokine downregulation.
TB-500 was placed on the FDA Category 2 restricted list in September 2023 — the same action that affected BPC-157. It is expected to return to Category 1 under the February 2026 reclassification announcement. WADA bans TB-500 under S0 (unapproved substances). USADA confirms no Therapeutic Use Exemption pathway exists for unapproved peptides including TB-500.
Why source quality matters specifically for TB-500: the 43-amino-acid length is a medium-complexity synthesis. TB-500 fragments — such as the Ac-SDKP tetrapeptide or the LKKTETQ heptapeptide — are cheaper to produce. Without mass spectrometry identity confirmation, a vial labelled "TB-500" could contain a truncated fragment, a different thymosin variant, or an entirely unrelated peptide.
7 Things to Check Before Ordering TB-500
The same 7-check framework applies to TB-500 — with particular attention to identity confirmation, since truncated fragments and thymosin variants are cheaper to produce and easily substituted.
1. Third-Party HPLC Purity (≥98%)
Check for a CoA from a named third-party lab showing ≥98% HPLC purity. TB-500's 43-amino-acid sequence produces more potential impurity peaks than BPC-157 (15 amino acids) but fewer than lipidated GLP-1 compounds. Cross-reference on peptigrity.com/lab-tests — filter by "TB-500." The study "Peptide Impurities in Commercial Synthetic Peptides" (PMC2238048) demonstrated that contamination at 1% of total peptide weight produced measurable biological effects in T-cell assays.
2. Mass Spectrometry Identity (~4,963 Da)
Mass spectrometry confirms the compound is full-length TB-500 and not a truncated fragment. TB-500 fragments (Ac-SDKP at ~487 Da, LKKTETQ at ~833 Da) have dramatically lower molecular weights — MS differentiates immediately. If MS shows a MW significantly below ~4,963 Da, the product is a fragment or a different compound entirely. Always request MS data for TB-500. See Mass Spectrometry for Peptides: Verifying Identity & Molecular Weight for the full methodology.
3. CoA From a Named, Verifiable Lab
Verify through the lab's online portal: Janoshik (Task #), Chromate (QR code + Job Number), Freedom Diagnostics (online system). For TB-500: confirm the CoA lists MW consistent with the full 43-amino-acid sequence — not a fragment. See Red Flags in Peptide Certificates of Analysis for the 12-point fraud detection checklist.
4. Independent Data on Peptigrity
Search peptigrity.com/lab-tests for the vendor + TB-500. Check the shop's profile on peptigrity.com/shops — trust score, ✓ Lab Verified badge, and TB-500-specific test count. Independent lab data submitted by Peptigrity's community carries more weight than vendor-published CoAs.
5. Community Reviews
Read reviews on the vendor's Peptigrity page. Each includes 5 sub-ratings: Quality, Delivery, Pricing, Customer Service, and Product Accuracy. TB-500 buyers often also purchase BPC-157 from the same vendor — check reviews mentioning both compounds for consistency signals.
6. Vial Presentation and Storage
Lyophilised TB-500 should be a white to off-white powder. TB-500 is not lipidated (unlike semaglutide or tirzepatide), so it has a standard oxidation profile — no heightened sensitivity from fatty acid modifications. Most RUO vendors ship at ambient temperature in standard tracked parcels. For 2–5 day domestic transit of lyophilised powder, this is acceptable. Store at −20°C on arrival. After reconstitution: 2–8°C, use within 28 days.
7. Pricing Reality Check
Research-grade TB-500 pricing (March 2026):
5 mg vial: $30–70.
10 mg vial: $50–120.
BPC-157 + TB-500 bundle: $60–140.
TB-500 pricing is similar to BPC-157. Below $20 for 5 mg is suspicious — synthesis of a 43-amino-acid peptide is not cheaper than BPC-157's 15 amino acids. Compare across vendors on Peptigrity. See Peptide Purity Standards: What Percentage Is Actually Acceptable? for the quality-price framework.
TB-500 on Peptigrity's Lab Test Database
Filter by TB-500 at peptigrity.com/lab-tests to compare independent purity data across vendors before ordering.
Community-submitted data from third-party laboratories represents real products from real buyers — not vendor marketing. Purity averages vary by vendor. Use the data before ordering to compare. If a vendor has multiple TB-500 tests on Peptigrity from named labs, that is the strongest quality signal available. If a vendor has zero tests, quality is unverified. Browse the TB-500 peptide guide for the complete compound profile alongside lab data.
TB-500 + BPC-157: The Most Common Peptide Stack
BPC-157 + TB-500 is the most commonly discussed peptide stack — BPC-157 for localised tissue repair and TB-500 for systemic healing via actin regulation and cell migration.
The complementary mechanisms: BPC-157 promotes localised tissue repair via growth hormone receptor upregulation and nitric oxide system modulation, primarily studied in tendon, muscle, and gastrointestinal models. TB-500 promotes systemic healing via G-actin sequestration and cell migration, primarily studied in wound healing, cardiac tissue, and inflammation models. No human clinical data exists for either compound individually or in combination as of 2026.
When buying both from the same vendor: verify each compound independently. A vendor with strong BPC-157 purity data on Peptigrity does not automatically have strong TB-500 data. Check both compounds on peptigrity.com/lab-tests separately. The 7-check framework applies to each vial, not to the vendor as a whole.
Stack pricing: $60–140 for BPC-157 + TB-500 bundles at most vendors. Compare bundle pricing against individual vial pricing — some vendors charge a premium for pre-packaged stacks while others offer genuine bundle discounts.
Frequently Asked Questions
What purity should research-grade TB-500 have?
≥98% HPLC from a third-party lab. TB-500's 43-amino-acid sequence is a medium-complexity synthesis with more potential impurity peaks than BPC-157. Cross-reference on peptigrity.com/lab-tests.
How much does research-grade TB-500 cost?
$30–70 for 5 mg, $50–120 for 10 mg. Similar pricing to BPC-157. Below $20 for 5 mg is suspicious. BPC-157 + TB-500 bundles: $60–140. Pricing changes frequently — compare across vendors on peptigrity.com/shops.
Is TB-500 the same as Thymosin Beta-4?
TB-500 is a synthetic peptide corresponding to the Tβ4 sequence. Most preclinical research is conducted on endogenous Thymosin Beta-4, not the synthetic version sold by research vendors. The assumption of equivalence is an extrapolation, not a demonstrated fact. A Phase 2 human trial on Tβ4 completed in 2009 never published results.
Is TB-500 legal in 2026?
TB-500 was placed on FDA Category 2 in September 2023. It is expected to return to Category 1 under the February 2026 reclassification announcement (formal list pending). RUO vendors are unaffected by this classification. WADA bans TB-500 under S0 for competitive athletes — no TUE pathway exists.
Can I stack TB-500 with BPC-157?
This is the most commonly discussed peptide stack. Verify each compound independently through Peptigrity — a vendor's BPC-157 quality does not guarantee their TB-500 quality. Check both compounds separately on peptigrity.com/lab-tests.
For the complete buyer verification framework, see How to Verify Peptide Quality Before You Buy and What to Look for in a Peptide Shop: A Buyer's Checklist. Browse all peptide shops ranked by trust score.
This article is for educational and informational purposes only and does not constitute medical advice. TB-500 is an investigational compound not approved by the FDA for human use. No human randomized controlled trials have been completed as of 2026. Research-grade TB-500 has no mandatory manufacturing standards. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.
