What is TB-500?
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.
| Type | Synthetic peptide fragment (17 amino acids) of thymosin beta-4 |
|---|---|
| Origin | Actin-binding region of thymosin beta-4, a 43-amino-acid protein |
| Also known as | TB500, thymosin beta-4 fragment, Tβ4 fragment |
| Evidence to date | Animal models of cell migration and repair; one review of thymosin beta-4; no large human trials of TB-500 |
| Form in this catalog | Inside the Wolverine, Glow and KLOW stacks; subcutaneous injection, supplied already reconstituted |
| Regulatory status | Compounded medication; not FDA-approved for any use |
| Anti-doping | Prohibited at all times (WADA, non-approved substances) |
| 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.
| 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 |
Get Wolverine Stack prescribed, pre-mixed
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.
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.
| 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.
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.
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.
Start your Wolverine Stack visit · from $183/mo- Wolverine Stack protocol: pricing, who it is for, FAQ
- Glow Stack protocol: pricing, who it is for, FAQ
- KLOW Stack protocol: pricing, who it is for, FAQ
- All recovery protocols compared
- BPC-157 Calculator: units, reconstitution and dosing chart
- What is BPC-157?
- BPC-157 vs TB-500: what is the difference?
- What is the Wolverine Stack?
References
- Thymosin beta4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opinion on Biological Therapy, 2012. doi:10.1517/14712598.2012.634793Study type: Review
- BPC 157 and its Role in Accelerating Musculoskeletal Soft-Tissue Healing. Cell and Tissue Research, 2019. doi:10.1007/s00441-019-03016-8Study type: Review
- BPC 157 and Standard Angiogenic Growth Factors: Tendon, Ligament, Muscle and Bone Healing. Current Pharmaceutical Design, 2018. doi:10.2174/1381612824666180712110447Study 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.