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TB-500

Thymosin Beta-4 fragment · Tβ4 17-23 · TB500

Last reviewed:

MW
≈888 Da
Research focus
tendon ligamentskin woundregenerationanti inflammatory

A synthetic peptide commonly described as a fragment of thymosin beta-4 incorporating the actin-binding 'LKKTETQ' motif. Studied for soft-tissue repair, wound healing, and cardiac tissue regeneration in animal models.

Mechanism of action

TB-500 is marketed as a synthetic peptide derived from the central actin-binding region of thymosin beta-4. The fragment is reported to bind G-actin, mobilise cellular migration, and upregulate VEGF and laminin-5 expression. Pre-clinical work additionally describes anti-inflammatory effects through suppression of NF-κB signalling.

Research history

Thymosin beta-4 was originally isolated from calf thymus in 1981 by Allan Goldstein. The 'TB-500' designation arose in the research-chemical market in the early 2000s; the precise composition of commercial TB-500 batches varies, and many preparations contain the 17-23 fragment rather than the full 43-amino-acid peptide.

Summarised studies

Thymosin β4 promotes the migration of endothelial cells

Smart N. et al., Nature · 2009

Full-length Tβ4 administration mobilised epicardial progenitor cells in adult murine hearts, contributing to coronary vasculogenesis after ischaemic injury.

Tβ4 accelerates dermal wound closure

Malinda K.M. et al., FASEB J · 2003

Topical application of thymosin beta-4 in murine full-thickness wound models reduced healing time by ~40% with increased angiogenesis and reduced inflammatory infiltrate.

TB-500 fragment effect on equine tendon healing

Veterinary observational series · 2015

Case-series reports in equine sports medicine describe accelerated return-to-work times after superficial digital flexor tendon injury when TB-500 was used alongside conventional rehabilitation; controlled trials are lacking.

Safety profile

Animal studies of both TB-500 and full-length thymosin beta-4 have reported a favourable acute toxicity profile. Long-term effects, immunogenicity, and the impact of pre-existing wounds or neoplastic tissue on outcomes are not adequately characterised. Batch identity is a major confounder in safety interpretation.

UK regulatory status

TB-500 is not licensed for human use in the UK and is prohibited under WADA S2 (Peptide hormones, growth factors, related substances and mimetics). Laboratory-only use is permitted; clinical administration is not.

Frequently asked questions

Is TB-500 the same as thymosin beta-4?
Not exactly. Full-length thymosin beta-4 is a 43-amino-acid peptide. Commercial TB-500 is typically a shorter synthetic fragment intended to retain the actin-binding region, but batch composition varies between suppliers.
Is TB-500 banned by WADA?
Yes. TB-500 falls under WADA category S2 and is prohibited in and out of competition for human athletes.
How is TB-500 typically reconstituted in research settings?
Lyophilised TB-500 is generally reconstituted with bacteriostatic or sterile water and stored refrigerated for short-term use, with −20 °C or colder recommended for longer storage.
What endpoints are common in TB-500 research?
Wound closure rate, angiogenesis (microvessel density), collagen fibre alignment, and gene expression of VEGF, laminin-5, and myosin heavy chain are frequently measured.
Does TB-500 cross the blood–brain barrier?
Penetration data are sparse. Some animal studies report distribution into central nervous system tissue, but the magnitude and clinical relevance remain unclear.

Where to source TB-500 for laboratory research

The following UK-based suppliers stock research-grade, lyophilised peptides for in-vitro and pre-clinical work. Purity and provenance vary; always request a Certificate of Analysis (CoA) and confirm cold-chain storage on arrival. None of the products linked below are approved for human use.

  • PeptideAuthority.co.uk

    UK-based research peptide supplier with batch certificates of analysis and >99% purity testing.

  • PeptideBarn.co.uk

    Wide catalogue of research-grade lyophilised peptides shipped from the UK, including bulk vials.

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