TB-500 is a synthetic fragment of Thymosin Beta-4, a naturally occurring 43-amino acid protein. It consists of the actin-binding domain of Thymosin Beta-4 and is studied for systemic tissue repair, cell migration, and anti-inflammatory effects.

How does TB-500 differ from BPC-157?

BPC-157 works through local angiogenesis and growth factor modulation. TB-500 works systemically through cell migration and actin polymerization regulation. They have complementary mechanisms and are frequently studied together as the Wolverine Stack.

Is TB-500 legal in 2026?

TB-500 was removed from FDA Category 2 on April 22, 2026. The PCAC is scheduled to evaluate it on July 23, 2026. It remains available from US research peptide vendors for research use only.

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

What Is TB-500?

TB-500 is a synthetic peptide corresponding to the actin-binding domain of Thymosin Beta-4 (Tβ4) — a naturally occurring 43-amino acid protein found throughout the body with particularly high concentrations in wound fluid and platelets. Thymosin Beta-4 was first identified in thymus tissue and has been studied for over 50 years; TB-500 is the most active fragment for research applications.

The key distinction between TB-500 and full Thymosin Beta-4 is practical: TB-500 contains the core actin-binding sequence responsible for Tβ4's primary research-relevant activities in a shorter, more cost-effective synthesized form.

⚠️ Research Use Only

TB-500 sold by Evo Peptides is for research use only. It is not FDA-approved and is not intended for human consumption.

Primary Mechanisms of Action

Actin Sequestration & Cell Migration

TB-500's primary mechanism is the regulation of actin dynamics — specifically, it sequesters G-actin (monomeric actin), modulating the equilibrium between G-actin and F-actin (filamentous actin). This regulation of actin polymerization is critical for cell motility. By modulating these dynamics, TB-500 promotes the migration of progenitor cells and endothelial cells to sites of injury — a process essential for tissue repair and angiogenesis.

Systemic Progenitor Cell Mobilization

Unlike BPC-157, which primarily acts locally, TB-500's effects are systemic. It mobilizes progenitor cells from bone marrow and other reservoirs into circulation, creating a body-wide pool of repair-competent cells. This systemic scope is why TB-500 has been studied in cardiac repair models — it can mobilize and direct cells to sites of damage regardless of location.

Anti-inflammatory Cytokine Modulation

TB-500 downregulates inflammatory cytokines including TNF-α, IL-1β, and IL-6 in preclinical injury models. This anti-inflammatory effect complements the repair-promoting mechanisms and reduces secondary tissue damage from inflammation at injury sites.

Blood Vessel Formation (Angiogenesis)

Through its effects on endothelial cell migration, TB-500 promotes angiogenesis — the formation of new blood vessels. This mechanism overlaps with BPC-157 but operates through a different pathway (cell migration vs. VEGF upregulation), which is part of the rationale for studying them together.

Key Research Areas

Cardiac Tissue Repair

One of the most clinically significant TB-500 research areas is myocardial repair. Multiple preclinical studies have examined TB-500's effects after ischemia-reperfusion injury, showing reduced infarct size, improved cardiac function, and evidence of cardiomyocyte regeneration. This cardiac research angle is relatively unique among tissue repair peptides.

Corneal Healing

The cornea contains high concentrations of natural Thymosin Beta-4, and the role of Tβ4/TB-500 in corneal wound healing has been studied extensively. Preclinical and early clinical research suggests accelerated corneal epithelial wound closure.

Musculoskeletal Repair

Like BPC-157, TB-500 has been studied in tendon, ligament, and muscle repair models. The systemic mobilization mechanism means TB-500's effects in musculoskeletal research complement rather than duplicate BPC-157's local angiogenic approach.

Research Specifications

Property	Value
Full name	Thymosin Beta-4 fragment (actin-binding domain)
Molecular weight	~4,963 Da
Appearance	White to off-white lyophilized powder
Solubility	Water soluble
Storage (lyophilized)	Refrigerated 2–8°C; freezer for long-term
Storage (reconstituted)	Up to 28 days at 2–8°C with BAC water
Purity (Evo Peptides)	≥98% by HPLC
FDA 2026 status	Removed from Category 2 · PCAC July 23

TB-500 vs. BPC-157: When to Use Which

Factor	TB-500	BPC-157
Mechanism scope	Systemic — body-wide cell mobilization	Local — angiogenesis at injury site
Onset	Slower — requires cell mobilization time	Faster local effect
Best for	Systemic repair, cardiac, diffuse injury	Localized injury, tendon/gut/bone
Oral bioavailability	Limited	Yes — relevant for gut research
Together (Wolverine)	Complementary — additive effect in repair research

Frequently Asked Questions

How is TB-500 different from Thymosin Beta-4?

Thymosin Beta-4 is the full 43-amino acid naturally occurring protein. TB-500 is a synthetic fragment consisting of the core actin-binding domain. TB-500 contains the primary bioactive sequence responsible for most of Tβ4's repair-related research activities in a shorter, more efficiently synthesized peptide form.

Is TB-500 on the July 2026 PCAC agenda?

Yes. TB-500 is on the Day 1 agenda of the July 23–24, 2026 PCAC hearing — the same session as BPC-157. It was removed from FDA Category 2 on April 22, 2026, along with BPC-157.

Why is TB-500 studied for cardiac repair?

The heart has limited regenerative capacity on its own. TB-500's ability to mobilize progenitor cells systemically and promote their migration to damaged cardiac tissue makes it one of the few non-stem-cell approaches to cardiomyocyte regeneration studied in preclinical models. The mechanism is distinct enough from other peptides to make it irreplaceable in cardiac repair research.

Research Use Disclaimer — TB-500 sold by Evo Peptides is for research use only and is not for human consumption.

TB-500:
Thymosin Beta-4 Fragment