What is TB-500 Fragment (17-23)?
TB-500 Fragment (17-23), also known as fequesetide or (17)(LKKTETQ)(23), is a synthetic peptide derived from the active region of thymosin beta-4. In research settings, this fragment has been observed to bind to actin, a cytoskeletal protein, potentially influencing cell structure, migration, and proliferation. Studies suggest that it may modulate immune responses and affect cell migration patterns, which could have implications for tissue repair and regeneration.
It represents the smallest active sequence of the thymosin beta-4 molecule that retains its actin-binding domain. Actin is integral to various cellular functions, including maintaining cell shape, facilitating movement, and supporting division. By interacting with actin, the fragment may influence cellular processes such as migration and proliferation. Research has focused on its potential roles in wound healing, inflammation modulation, and tissue regeneration.
New Update: In July 2026, an FDA advisory committee narrowly voted to recommend TB-500 (thymosin beta-4) for the 503A compounding list. It has not been added to that list or approved for human use, and further rulemaking would be required. TB-500 is sold for research use only.
Structure
- Chemical Formula: C36H66N10O13
- Synonyms: Fequesetide, Thymosin Beta-4(17-23), (17)(LKKTETQ)(23)
TB-500 Fragment (17-23) Research
The Role of Actin in Cell Function
Actin is a fundamental protein within eukaryotic cells, playing a pivotal role in maintaining cell shape, enabling movement, and facilitating division. It exists in two forms: monomeric (G-actin) and polymerized (F-actin). The dynamic equilibrium between these forms is crucial for cellular functions. The fragment has been observed to bind to actin, potentially influencing this balance and affecting processes such as cell migration and proliferation.
Thymosin Beta-4: The Parent Molecule
Thymosin beta-4 is a naturally occurring peptide present in many tissues. It is known for its actin-binding properties, which are essential for various cellular activities, including tissue regeneration and inflammation modulation. TB-500 Fragment (17-23) is derived from this parent molecule, retaining the active site responsible for actin interaction.
Thymosin Beta-4 Derivatives
Derivatives of thymosin beta-4, such as TB-500 Fragment (17-23), have been synthesized to focus on specific functional domains of the parent molecule. These derivatives are studied for their potential to selectively influence cellular processes like migration and proliferation, which are critical in tissue repair mechanisms.
Healing
Research indicates that the fragment may play a role in tissue repair processes. Its interaction with actin could influence cell migration and proliferation, essential components of wound healing. Studies have explored its potential in promoting endothelial cell differentiation and angiogenesis, processes vital for effective tissue regeneration.
Musculoskeletal Performance
In experimental models, the fragment has been investigated for its potential effects on musculoskeletal tissues. Its interaction with actin may influence muscle cell function and recovery processes, suggesting possible applications in studies related to muscle performance and repair.
Inflammation
The fragment has been studied for its potential role in modulating inflammatory responses. By influencing actin dynamics, it may affect the behavior of inflammatory cells, potentially contributing to the regulation of inflammation in various tissue types.
Cell Signaling
Actin plays a role in various cell signaling pathways. Its interaction with actin may influence these pathways, potentially affecting processes such as cell growth, differentiation, and response to external stimuli.
Neurological Restoration
Emerging research has explored the fragment’s potential effects on neurological tissues. Its influence on cell migration and proliferation may have implications for studies focused on nerve regeneration and neurological recovery processes.
Summary
TB-500 Fragment (17-23) is a synthetic peptide derived from thymosin beta-4, focusing on its actin-binding domain. Research has investigated its potential roles in influencing cell migration, proliferation, and tissue repair processes. While studies are ongoing, it continues to be a subject of interest in various fields of biomedical research.
Reconstitution and dosing
TB-500 is typically reconstituted with bacteriostatic water at 5 to 10 mg per ml. Standard dosing is 250 mcg twice per day up to 1000 mcg twice per day for acute injuries. In wellness cycles, it is used in an 8-week on, 8-week off schedule.
For our free peptide calculator, CLICK HERE. Research-grade TB-500 is available from WellnessPeptides.
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