PeptidePedia
Animal / Lab

TB-500

A synthetic fragment of thymosin beta-4 studied in animals for wound healing, cardiac repair, and tissue regeneration.

In plain English

TB-500 is a synthetic peptide closely related to thymosin beta-4 (Tβ4), a naturally occurring protein involved in cell migration and tissue repair. In animal models — including rodents and horses — TB-500 and full-length Tβ4 have been associated with faster wound closure, improved cardiac repair after injury, and modulation of inflammation. Despite heavy use in equine sports and recovery circles, TB-500 has no published large human trials and is not FDA-approved. It is explicitly banned by WADA. People commonly research TB-500 for soft-tissue and tendon injury recovery and general repair, but the human evidence is almost entirely absent.

What it is

TB-500 is a synthetic peptide based on a region of thymosin beta-4, a 43-amino-acid actin-binding protein abundant in tissues including platelets and wound fluid.

Mechanism (summary)

Thymosin beta-4 binds G-actin, modulating cytoskeletal dynamics, cell migration, angiogenesis, and inflammation. TB-500 is thought to share some of these activities, particularly relating to wound healing and cardiac repair signaling.

Why people research it

  • Wound healing in animal injury models
  • Cardiac repair after experimental infarction
  • Tendon and ligament repair in horses
  • Corneal wound healing

Human evidence

Full-length thymosin beta-4 (RGN-259, TB4) has been studied in small human trials for dry eye and corneal ulcer, but TB-500 specifically lacks published, peer-reviewed RCTs for the soft-tissue or recovery uses for which it is commonly marketed.

Animal / lab evidence

Animal data, mainly in rodents and horses, suggest improved wound closure, modulation of inflammation, and protective effects after cardiac injury.

Key studies

Each summary explains the design, what was found, and what it doesn't prove.

Review2012·Animal model review (mice, rats, pigs)
Thymosin beta 4 and cardiac repair

In animals with experimentally damaged hearts, thymosin beta-4 helped protect heart cells and improve recovery.

Finding: Thymosin beta-4 promoted survival of cardiac cells and improved function after experimental heart attack in multiple animal models.
Limitations: Animal-only data; human cardiac trials of Tβ4 have not replicated these effects at scale.
In vitro2008·Human endothelial cells (cell culture)
Thymosin β4 promotes the migration of endothelial cells without intracellular Ca2+ elevation

In a dish, Tβ4 made the cells that line blood vessels move around — a behavior linked to growing new vessels during healing.

Finding: Thymosin β4 caused endothelial cells (cells that line blood vessels) to migrate, which supports a role in new vessel formation during wound healing.
Limitations: Cell culture only.
Human RCT2014·Adults with moderate-to-severe dry eye disease
Topical RGN-259 (Thymosin Beta 4) for Dry Eye Disease: A Phase 2 Trial

An eye-drop version of the parent protein helped dry-eye symptoms in a small trial — but this isn't the same as the injected TB-500 used in recovery circles.

Finding: Topical full-length thymosin beta-4 eye drops modestly improved dry-eye symptoms vs. vehicle in a Phase 2 trial.
Limitations: This studied an eye-drop formulation of full-length Tβ4, not injected TB-500. Results do not transfer to tendon or soft-tissue use.

History

TB-500 was popularized in the late 2000s in equine veterinary use and recovery communities. Full-length Tβ4 has been the subject of clinical trials in eye and skin conditions but TB-500 specifically has not.

Important:

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