> ## Site index > Full index of Peptides.build at https://peptides.build/llms.txt. Use it to discover every page. # What Is TB-500? Thymosin Beta-4 Fragment TB-500 explained: the synthetic thymosin beta-4 fragment, what animal and review research covers, the stacks it is prescribed in, and its FDA and sport status. URL: https://peptides.build/learn/what-is-tb-500/ Guide · Recovery # What is TB-500? Published October 12, 2026 · Educational, not medical advice ## Short answer TB-500 is a synthetic peptide matching the actin-binding region of thymosin beta-4, a 43-amino-acid protein. It has been studied in animal models for cell migration and tissue repair, with no large human trials of TB-500 itself. Through Peptides.build it is prescribed only inside stacks with BPC-157, as a compounded medication, and compounded medications are not FDA-approved. It is prohibited in sport. - [Where does TB-500 come from?](#origin) - [What has TB-500 been studied for?](#research) - [How is TB-500 prescribed?](#prescribed) - [Is TB-500 FDA-approved or allowed in sport?](#status) - [How are TB-500 doses measured?](#units) - [FAQ](#faq) - [References](#references)
TB-500 quick facts
TypeSynthetic peptide fragment (17 amino acids) of thymosin beta-4
OriginActin-binding region of thymosin beta-4, a 43-amino-acid protein
Also known asTB500, thymosin beta-4 fragment, Tβ4 fragment
Evidence to dateAnimal models of cell migration and repair; one review of thymosin beta-4; no large human trials of TB-500
Form in this catalogInside the Wolverine, Glow and KLOW stacks; subcutaneous injection, supplied already reconstituted
Regulatory statusCompounded medication; not FDA-approved for any use
Anti-dopingProhibited at all times (WADA, non-approved substances)
Evidence snapshot**What kind of research is cited for TB-500?**3 cited sources: 3 review articles. Counts describe study type, not strength of result. Sources cited for TB-500, by study type | Study type | Sources | | --- | --- | | Human clinical trials | 0 | | Other human studies | 0 | | Animal and lab studies | 0 | | Review articles | 3 | ## Where does TB-500 come from? TB-500 is a synthetic copy of one region of thymosin beta-4, a 43-amino-acid protein. Thymosin beta-4 binds actin, the protein that cells use to build their internal scaffolding and to move, and the short stretch that does the binding contains the sequence LKKTETQ. TB-500 is a 17-amino-acid fragment built around that stretch, which is why it is often described as the active fragment of thymosin beta-4, although 'active' refers to what it binds, not to any proven effect in people. The name comes from thymosin beta-4's original isolation from thymus tissue; as prescribed, TB-500 is entirely synthetic. A compounding pharmacy assembles the 17-residue sequence rather than extracting anything from tissue, and a synthetic fragment with no approved product behind it can only reach a patient through a prescription for a compounded medication. ## What has TB-500 been studied for? TB-500 research is mostly animal work, and much of the literature is about the parent protein, thymosin beta-4, rather than the fragment. The review in this article's references describes thymosin beta-4's basic properties and the clinical applications that have been explored for it, and the animal studies behind TB-500 look at cell migration, the movement of cells into injured tissue, and at tissue repair in injury models. What is missing is a published, large, randomized trial of TB-500 in people. Thymosin beta-4 itself has been taken into clinical research, but a fragment is not the same molecule and results do not transfer automatically. The careful reading is the same as for BPC-157: a consistent preclinical signal, thin human data, and no page that can honestly tell you what it will do for you. What the published research covers | Area | Type of evidence | What the reviews describe | | --- | --- | --- | | Cell migration | Animal and cell studies | Movement of cells into injured tissue, tied to actin binding | | Tissue repair | Animal models | Wound and injury models, mostly of thymosin beta-4 | | Parent protein | Review | Basic properties and clinical applications of thymosin beta-4 | | Humans (TB-500) | No large trials published | Fragment-specific human data is thin | Prescribed, pre-mixed ## Get Wolverine Stack prescribed, pre-mixed US-supervised · all 50 states [Wolverine Peptide Stack](https://peptides.build/protocols/wolverine-stack/)Blend: outside the HHS policy **$183**/mo*$1,099 billed every 6 months* Pay over time at checkout![Klarna](/media/payments/klarna.png)![Afterpay](/media/payments/afterpay.png)![Affirm](/media/payments/affirm.png) Prescription required. Your provider decides if it is appropriate. Compounded medications are not FDA-approved. US-supervised · all 50 states [GLOW Peptide Stack](https://peptides.build/protocols/glow-stack/)Blend: outside the HHS policy **$183**/mo*$1,099 billed every 6 months* Pay over time at checkout![Klarna](/media/payments/klarna.png)![Afterpay](/media/payments/afterpay.png)![Affirm](/media/payments/affirm.png) Prescription required. Your provider decides if it is appropriate. Compounded medications are not FDA-approved. ## How is TB-500 prescribed? TB-500 is not prescribed on its own through Peptides.build. It appears in three stacks: the Wolverine Stack, which pairs it with BPC-157 in one vial; the Glow Stack, which adds GHK-Cu; and the KLOW Stack, which adds GHK-Cu and KPV. Each is a compounded medication prescribed by a licensed US provider for an individual patient and prepared by a licensed 503A pharmacy. BPC-157's own literature, reviewed in the references, covers tendon, ligament and muscle models, which is the overlap that explains the pairing. Every stack ships as a subcutaneous injection, already reconstituted, with each compound's concentration printed on the pharmacy label, so there is no powder to mix. Which stack, if any, fits a patient's history is decided during intake, and the dose of TB-500 inside it is set by the provider and never published here. ## Is TB-500 FDA-approved or allowed in sport? TB-500 is not FDA-approved for any use. When TB-500 reaches a patient it does so inside a compounded medication, and compounded medications are not FDA-approved. That is true of every stack it appears in and is stated on each protocol page. In sport, TB-500 is prohibited at all times. The World Anti-Doping Agency lists it among non-approved substances, the same category as BPC-157, so every stack in this catalog that contains TB-500 is off limits to drug-tested athletes, who should check with their governing body. ## How are TB-500 doses measured? TB-500 inside a stack is measured through the same label as the BPC-157 it is blended with. In a blend vial both peptides dissolve in the same liquid, so every unit drawn on a U-100 insulin syringe carries both compounds in the ratio printed on the label, and the two amounts cannot be adjusted separately. The free BPC-157 calculator on this site has a blend mode: enter the BPC-157 amount on the prescription and the label strengths, and it shows the units to draw and how much TB-500 comes with them. It does arithmetic only and does not recommend a dose. Prescription, not research grade ## Prescribed TB-500 vs research peptides: what is different? Prescribed TB-500 is not a research chemical. It is a prescription medication: a licensed US provider reviews your intake first, and a licensed 503A pharmacy compounds it for you by name. Vials sold online as “research use only” skip both steps. What you pay for here is that review, a pharmacy you can name, and a label that says what is in the vial. A research seller’s certificate of analysis is a document the seller controls: it chooses the lab and the sample, and a PDF can be reused, edited or re-dated. No regulator checks it. Prescribed TB-500 compared with research-use-only peptides | Point | Prescribed through Peptides.build | Research use only | | --- | --- | --- | | Access | Online intake reviewed by a licensed US provider; prescribed only when appropriate. | No prescription and no clinical review of whether it suits you. | | How it's labeled | A prescription medication compounded for you by name. | Commonly sold labeled “research use only, not for human consumption.” | | Who prepares it | A licensed 503A US compounding pharmacy under state and federal oversight. | Unregulated suppliers, often with no verifiable chain of custody. | | Testing | Third-party tested. | Certificates of analysis are self-reported when provided at all. | | Purity and identity | Prepared to a prescription for a specific patient. | Purity, strength, and even identity are unverified by any independent party. | This compares two care models, not two products. Compounded medications are not FDA-approved, and we do not claim otherwise. What a prescription adds is a licensed provider deciding whether a protocol is appropriate for you and a licensed pharmacy preparing it. [Read the full guide to research vs prescription peptides](https://peptides.build/learn/research-peptides-vs-prescription-peptides/). Common questions ## TB-500 FAQ ### Is TB-500 the same as thymosin beta-4? No. Thymosin beta-4 is a 43-amino-acid protein; TB-500 is a synthetic 17-amino-acid fragment of it that contains the actin-binding sequence. Most published research is on the parent protein, so claims about TB-500 often borrow from it. ### Can I get TB-500 on its own? Not through Peptides.build. It is prescribed only inside the Wolverine, Glow and KLOW stacks, each of which also contains BPC-157. A provider decides which stack, if any, fits your history. ### Has TB-500 been tested in humans? Thymosin beta-4 has been studied in clinical research, as the review in the references describes, but large randomized trials of the TB-500 fragment itself have not been published. The evidence for the fragment is animal and cell work. ### Is TB-500 banned in sport? Yes. The World Anti-Doping Agency lists TB-500 among prohibited non-approved substances, banned at all times, alongside BPC-157. Drug-tested athletes should check with their governing body. ### Is TB-500 FDA-approved? No. TB-500 is not FDA-approved for any use. It reaches patients only as part of a compounded medication prescribed by a licensed provider, and compounded medications are not FDA-approved. Prescribed, not mixed at home ## Wolverine Stack through Peptides.build A licensed US provider reviews a short online intake and decides whether a protocol is appropriate. A US 503A pharmacy prepares it already reconstituted, labels the concentration and ships it cold-chain. Dosing is set by the provider and is not published on this site. - [Wolverine Stack protocol: pricing, who it is for, FAQ](https://peptides.build/protocols/wolverine-stack/) - [Glow Stack protocol: pricing, who it is for, FAQ](https://peptides.build/protocols/glow-stack/) - [KLOW Stack protocol: pricing, who it is for, FAQ](https://peptides.build/protocols/klow-stack/) - [All recovery protocols compared](https://peptides.build/protocols/recovery/) - [BPC-157 Calculator: units, reconstitution and dosing chart](https://peptides.build/tools/bpc-157-calculator/) - [What is BPC-157?](https://peptides.build/learn/what-is-bpc-157/) - [BPC-157 vs TB-500: what is the difference?](https://peptides.build/learn/bpc-157-vs-tb-500/) - [What is the Wolverine Stack?](https://peptides.build/learn/what-is-the-wolverine-stack/) Sources ## References 1. Thymosin beta4: a multi-functional regenerative peptide. Basic properties and clinical applications. *Expert Opinion on Biological Therapy*, 2012. [doi:10.1517/14712598.2012.634793](https://doi.org/10.1517/14712598.2012.634793)Study type: Review 2. BPC 157 and its Role in Accelerating Musculoskeletal Soft-Tissue Healing. *Cell and Tissue Research*, 2019. [doi:10.1007/s00441-019-03016-8](https://doi.org/10.1007/s00441-019-03016-8)Study type: Review 3. BPC 157 and Standard Angiogenic Growth Factors: Tendon, Ligament, Muscle and Bone Healing. *Current Pharmaceutical Design*, 2018. [doi:10.2174/1381612824666180712110447](https://doi.org/10.2174/1381612824666180712110447)Study type: Review Citations are listed with their study type so the evidence can be weighed. Review articles summarize other studies; animal and in vitro findings do not describe outcomes in people. This article is educational and is not medical advice. TB-500 is not FDA-approved for any use, and compounded medications are not FDA-approved. No results are implied or guaranteed. Talk to a licensed provider about your own history before starting any protocol.