TB-500: Complete Guide
TB-500 is a synthetic version of a 43-amino-acid region of thymosin beta-4 (Tβ4), a naturally occurring peptide present in virtually all human cells. Thymosin beta-4 plays a central role in tissue repair, cell migration, blood vessel formation, and inflammation regulation. TB-500 is widely studied in veterinary medicine (particularly equine recovery) and has generated significant research interest for human tissue repair applications.
Last updated: 2026-01-28
Quick Facts
- Category
- therapeutic
- Also Known As
- Thymosin Beta-4 Fragment
- Related Goals
- healing, inflammation
Who Researches TB-500?
TB-500 is researched by people recovering from injuries — muscle tears, tendon damage, ligament sprains, and surgical recovery. It's one of the most popular healing peptides, often called the "systemic repair" peptide because it works throughout the body rather than at a specific site. Athletes, weekend warriors, and anyone dealing with slow-healing injuries are the primary research demographic. TB-500 is almost always discussed alongside BPC-157 — the two are frequently combined because TB-500 handles systemic repair while BPC-157 targets localized healing and blood vessel growth.
Related Resources
- Stacks: Healing Stack · Recovery Stack · Joint Mobility Stack
- Comparisons: BPC-157 vs TB-500 · Thymosin Beta-4 vs TB-500
TB-500
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What Is TB-500?
TB-500 contains the active region of thymosin beta-4, centered around the actin-binding domain with the sequence LKKTETQ. This region is responsible for the peptide's key biological activities — promoting cell migration, reducing inflammation, and supporting tissue repair.
Thymosin beta-4 itself is one of the most abundant intracellular peptides, found in all cells except red blood cells. It regulates actin polymerization, which controls cell shape, movement, and division. When tissue is damaged, thymosin beta-4 is released and acts as a signaling molecule to recruit repair cells and coordinate the healing response.
TB-500 has been most extensively used in veterinary medicine, where it is a well-known treatment for equine injuries. Its use in racehorses for tendon, ligament, and muscle recovery is widespread and has provided substantial real-world data on its efficacy and safety in large mammals.
Mechanism of Action
- Cell migration: TB-500 promotes the migration of endothelial cells, keratinocytes, and stem cells to injury sites by modulating actin dynamics
- Angiogenesis: Stimulates the formation of new blood vessels to supply healing tissue with oxygen and nutrients
- Anti-inflammatory: Reduces pro-inflammatory cytokine production and modulates immune cell activity at injury sites
- Extracellular matrix remodeling: Promotes appropriate collagen deposition and matrix metalloproteinase regulation for organized tissue repair
- Cardiac repair: Research shows thymosin beta-4 promotes cardiac progenitor cell activation and reduces scar formation after myocardial injury
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Dosage Overview
| Phase | Dose | Frequency | Duration |
|---|---|---|---|
| Loading | 2–2.5 mg | Twice weekly | 4–6 weeks |
| Maintenance | 2–2.5 mg | Once weekly or biweekly | Ongoing as needed |
TB-500's longer half-life compared to most peptides allows for less frequent dosing. Use the peptide calculator for reconstitution.
Side Effects & Safety
- Generally well-tolerated in both animal and human research
- Injection site reactions: Mild redness — most common
- Head rush: Transient lightheadedness reported by some users after injection
- Lethargy: Temporary tiredness reported occasionally
- Theoretical tumor concern: Thymosin beta-4 is upregulated in some tumor environments, though no evidence of tumor promotion from exogenous TB-500 has been reported
TB-500 is often compared to BPC-157 — they target complementary healing mechanisms and are sometimes studied together.