TB-500 (Thymosin Beta-4): Research Guide [2026]

TB-500 is the synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino acid peptide found in nearly all human and animal cells. It plays a central role in tissue repair, cell migration, and inflammation regulation. This guide covers what researchers need to know about TB-500 – from its molecular mechanisms to practical research considerations.

What Is TB-500?

Thymosin Beta-4 was first isolated from the thymus gland in the 1960s by Allan Goldstein at the National Institutes of Health. It is the most abundant member of the beta-thymosin family – a group of small, highly conserved peptides found across vertebrate species.

TB-500 is a synthetic fragment of Thymosin Beta-4, not identical to the full 43-amino acid protein. It replicates the active region of Tb4 responsible for its key biological effects. While the full Tβ4 protein is 43 amino acids long, TB-500 focuses on the key active domain responsible for actin binding and cell migration properties.

Unlike many research peptides, Thymosin Beta-4 occurs naturally at high concentrations throughout the body. It is found in blood platelets, wound fluid, and virtually all nucleated cells. This widespread presence reflects its fundamental role in cellular processes related to healing and development.

TB-500 is sometimes studied alongside BPC-157, as the two peptides appear to support tissue repair through different but complementary pathways.

Mechanism of Action

TB-500’s biological activity centers on its interaction with actin, a protein that forms the structural framework (cytoskeleton) of cells. Here’s how it works:

Actin Sequestration

TB-500 binds to G-actin (monomeric actin) and prevents it from polymerizing into F-actin (filamentous actin) prematurely. This regulation of actin dynamics is essential for cell movement. By controlling when and where actin filaments form, TB-500 allows cells to migrate to injury sites more effectively (PMID: 20101715).

Cell Migration Promotion

The peptide upregulates cell migration by promoting the formation of new actin structures at the leading edge of migrating cells. This is particularly important for wound healing, where keratinocytes, endothelial cells, and other repair cells need to move into the damaged area.

Anti-Inflammatory Properties

TB-500 has demonstrated anti-inflammatory effects in multiple models. It appears to downregulate inflammatory cytokines while supporting the resolution phase of inflammation – the stage where the body transitions from fighting damage to repairing it (PMID: 20564531).

Angiogenesis

Like BPC-157, TB-500 promotes the formation of new blood vessels. It stimulates endothelial cell differentiation and migration, supporting the development of new vasculature in healing tissues.

Key Research Findings

Cardiac Repair

Some of the most significant TB-500 research has focused on cardiac tissue. A landmark study by Bock-Marquette et al. (2004) published in Nature showed that Thymosin Beta-4 promoted survival of cardiac myocytes (heart muscle cells) after ischemic injury. The peptide activated the Akt survival pathway, reducing cell death after simulated heart attack conditions (PMID: 15229613).

Follow-up research demonstrated that Tβ4 could stimulate the formation of new coronary vessels and improve cardiac function after myocardial infarction in mouse models (PMID: 17322904).

Wound Healing

Thymosin Beta-4 has been extensively studied for dermal wound healing. Research shows it accelerates wound closure by promoting keratinocyte migration, collagen deposition, and angiogenesis. Philp et al. (2004) demonstrated that topical application of Tβ4 increased wound healing rates in rat models (PMID: 14688025).

Corneal Healing

TB-500 research has shown particular promise in ocular applications. Studies have demonstrated accelerated corneal wound healing with Tβ4 treatment. A clinical product based on this research (RGN-259) has undergone Phase 2 clinical trials for dry eye syndrome and neurotrophic keratopathy (PMID: 22414958).

Hair Growth

An interesting secondary finding from wound healing studies was that Tβ4 promoted hair growth in mice. Philp et al. (2004) observed that areas treated with Tβ4 showed increased hair follicle stem cell activity and accelerated hair growth (PMID: 14688025).

Neurological Research

Studies in traumatic brain injury (TBI) models have shown that Tβ4 treatment improved neurological outcomes. Research published by Xiong et al. (2012) demonstrated that Tβ4 promoted neurovascular remodeling and improved functional recovery after TBI in rats (PMID: 22155315).

Clinical Trials

Unlike many research peptides, Thymosin Beta-4 has entered human clinical trials. RegeneRx Biopharmaceuticals developed RGN-259 (a topical Tβ4 formulation) for eye conditions. These trials provide some of the limited human safety data available for this peptide.

Common Research Applications

• Wound healing and tissue repair mechanisms
• Cardiac repair after ischemic injury
• Corneal wound healing and dry eye research
• Anti-inflammatory pathway studies
• Actin cytoskeleton dynamics research
• Neurological recovery after traumatic brain injury
• Musculoskeletal injury repair (tendons, ligaments)
• Hair follicle stem cell activation studies

Reconstitution and Dosing Information

Note: This information is for research purposes only. TB-500 is not approved for human use.

Reconstitution

TB-500 is supplied as a lyophilized powder, typically in 2 mg or 5 mg vials. To reconstitute:

1. Allow the vial to reach room temperature before opening
2. Use bacteriostatic water as the solvent
3. Add the water slowly down the inner wall of the vial
4. Gently swirl until fully dissolved – the solution should be clear
5. Do not shake or vortex aggressively

A standard reconstitution is 1 mL of BAC water per 2 mg vial, giving a concentration of 2 mg/mL.

Research Dosing

In animal studies, TB-500 has been administered at various doses depending on the model. Equine studies (TB-500 has been widely researched in racehorses) typically used doses in the range of 10-20 mg per treatment. Rodent studies have used doses scaled to body weight, generally in the range of 6 mg/kg intraperitoneally.

Administration routes in research include subcutaneous injection, intramuscular injection, intraperitoneal injection, and topical application (for wound healing studies).

Storage Requirements

• Lyophilized powder: Store at -20°C for long-term stability. The peptide is relatively stable and can tolerate brief periods at room temperature (during shipping), but should be frozen upon receipt.
• Reconstituted solution: Refrigerate at 2-8°C. Use within 2-3 weeks.
• Avoid: Multiple freeze-thaw cycles, prolonged light exposure, and contamination during handling.
• Shelf life: Lyophilized TB-500 is generally stable for 12-24 months when stored properly at -20°C.

Potential Side Effects from Research Literature

Thymosin Beta-4 has demonstrated a generally favorable safety profile in both animal studies and limited human clinical trials:

• Clinical trial safety data: Phase 2 trials of RGN-259 (topical Tβ4 for eye conditions) reported no serious adverse events related to the drug.
• Theoretical cancer concerns: Because Tβ4 is often found at elevated levels in tumor cells, there have been questions about whether exogenous administration could promote cancer growth. Current research suggests Tβ4 does not initiate cancer but may be involved in metastatic processes. This remains an area of active investigation (PMID: 17325556).
• Injection site reactions: Minor localized reactions (redness, swelling) at injection sites have been reported in animal studies.
• Equine studies: Large-scale use in racehorses has not revealed significant safety issues, though this data is limited in its applicability to other species.

Where to Source Quality TB-500

When purchasing TB-500 for research, quality verification is essential. Key factors to evaluate:

• Purity testing: Look for HPLC purity reports showing 98% or higher purity
• Identity confirmation: Mass spectrometry data confirming the correct molecular weight (4,963 Da for the full Tβ4 sequence)
• Endotoxin testing: Particularly important for injectable research applications
• Batch-specific COAs: Certificates of Analysis should be available for each production batch, not generic templates

For our detailed comparison of peptide suppliers rated on purity, price, testing standards, and reliability, see Best Peptide Companies [2026].

Frequently Asked Questions

Disclaimer: This article is for informational and research purposes only. TB-500 is not approved for human use. Nothing in this guide should be taken as medical advice. Always consult a qualified healthcare professional before making any health-related decisions.