TB-500 is a synthetic peptide derived from thymosin beta-4, a naturally occurring protein found in almost all human and animal cells. Thymosin beta-4 is best known for binding actin, a building block of the cell skeleton, and it has been studied in models of wound healing, cell migration and tissue repair. This guide explains what TB-500 is, the mechanisms investigated, and how it is handled in the lab.
What is TB-500?
Thymosin beta-4 is a 43-amino-acid protein that is one of the most abundant actin-binding molecules in cells. It is found at high levels in platelets and white blood cells and is released at sites of tissue injury, which is one reason it has drawn interest in repair research.
The name TB-500 is used for synthetic peptides based on thymosin beta-4. It is commonly associated with the protein's central actin-binding region, which includes the short motif LKKTETQ. In practice, the name has been applied both to fragments and to the full-length sequence, so researchers should check the product specification and COA to confirm exactly which sequence they have.
TB-500 should not be confused with thymosin alpha-1, which is a different peptide with a different sequence and a different research focus on immune function.
TB-500 is not an approved medicine in the US. Thymosin beta-4 and its derivatives are also on the World Anti-Doping Agency's prohibited list. PRIME supplies TB-500 as a research compound for laboratory use only.
How TB-500 works: mechanism studied in research
Most mechanistic research focuses on thymosin beta-4 and its active regions. The main lines of investigation include:
- Actin sequestration: thymosin beta-4 binds monomeric G-actin and helps regulate the pool of actin available to build filaments. This is central to how cells change shape and move.
- Cell migration: by influencing actin dynamics, thymosin beta-4 has been studied for effects on the migration of cells such as keratinocytes and endothelial cells into injured areas.
- Angiogenesis: research in cell and animal models has examined its role in the formation of new blood vessels.
- Inflammation signaling: studies have explored effects on inflammatory mediators in injury models.
Short fragments containing the actin-binding motif have been used to test which parts of the full protein are responsible for particular effects. How closely any specific TB-500 product reproduces the activity of full-length thymosin beta-4 depends on its sequence, which is another reason to confirm the specification.
Another feature of thymosin beta-4 that interests researchers is its distribution. Because it is present in nearly every cell type and released from platelets at sites of injury, it has been proposed to act as an early signal in the repair process. That broad presence also makes experiments more complex, since endogenous thymosin beta-4 is already present in most tissues. Well-designed studies therefore account for baseline levels and use appropriate controls when testing a synthetic fragment or the full-length protein.
Areas of TB-500 research
Research on thymosin beta-4 and TB-500 covers several areas:
- Dermal wound healing in animal models
- Corneal and eye surface repair models
- Cardiac tissue research in animal models
- Muscle, tendon and ligament injury models
- Hair follicle biology
- Angiogenesis and endothelial cell migration
- Actin cytoskeleton biology in cell culture
Thymosin beta-4 itself has been examined in clinical research, including ophthalmic formulations, but neither thymosin beta-4 nor TB-500 is approved to treat any condition in the US. Findings from animal and cell models should not be read as evidence of benefit or safety in humans.
TB-500 key facts
| Property | Detail |
|---|---|
| Class | Synthetic peptide derived from thymosin beta-4 |
| Parent protein | Thymosin beta-4, a 43-amino-acid actin-binding protein |
| Key motif | LKKTETQ (central actin-binding region) |
| Other names | Thymosin beta-4 fragment, TB4, Tβ4 (parent protein) |
| Form supplied | Lyophilized powder in a sealed vial |
| Research status | Research compound; not an FDA-approved medicine; prohibited in sport by WADA |
| Main research areas | Wound healing, cell migration, angiogenesis, cardiac and eye models |
| Storage | Lyophilized: cold, dry and dark. Reconstituted: refrigerated and protected from light |
Handling and storage of TB-500 in the lab
TB-500 is supplied as a lyophilized powder, the most stable form for shipping and storage. Keep unopened vials cold, dry and away from light, using a freezer for longer holding periods and a refrigerator for material in active use.
When a solution is needed, researchers commonly reconstitute with bacteriostatic water using sterile technique:
- Allow the vial to reach room temperature before opening.
- Swab the stopper with alcohol.
- Add diluent slowly down the inside wall of the vial.
- Swirl gently until the powder dissolves; do not shake.
- Label with the date and concentration used, then refrigerate and protect from light.
Use reconstituted material within the period set by your lab's procedures and avoid repeated freeze-thaw cycles. Any cloudiness or particles are a reason to check the material before use.
Quality and lab results
Since the TB-500 name covers more than one possible sequence, the certificate of analysis matters more than usual. Every PRIME batch has a published COA, and you can check each batch report on our lab results page. A COA typically confirms identity by mass spectrometry, which also shows which sequence is present, and reports purity by HPLC. Match the lot number on your vial to the report before use.
Related research
TB-500 is most often studied alongside BPC-157. See BPC-157 vs TB-500 for a side-by-side comparison and the BPC-157 research guide for more on that compound. To avoid mixing up the two thymosins, the Thymosin Alpha-1 research guide explains how that immune-focused peptide differs.
TB-500 FAQ
Is TB-500 the same as thymosin beta-4?
Not always. Thymosin beta-4 is a 43-amino-acid protein. TB-500 is a synthetic peptide based on it, commonly associated with its actin-binding region. The name has been used for both fragments and the full sequence, so check the COA.
What is TB-500 studied for?
TB-500 and thymosin beta-4 have been studied in models of wound healing, cell migration, angiogenesis, and cardiac, eye and musculoskeletal repair. It is a research compound and is not approved to treat any condition.
Is TB-500 FDA approved?
No. TB-500 is not an FDA-approved medicine. PRIME sells it for laboratory research use only, not for human consumption.
What is the difference between TB-500 and thymosin alpha-1?
They are different peptides. TB-500 is derived from thymosin beta-4 and is studied for actin regulation and tissue repair. Thymosin alpha-1 has a different sequence and is studied mainly in immune research.
How should TB-500 be stored?
Keep lyophilized TB-500 cold, dry and away from light. After reconstitution for lab use, store it refrigerated, protected from light, and use it within your lab's defined period.
For laboratory research use only. Not for human consumption. Not a drug, food or cosmetic.