TB-500

In simple words

TB-500 is a short synthetic piece of the thymosin beta-4 protein, designed to mimic its ability to help cells move to the site of injury. It is studied for recovery of muscles, tendons, and joints, but it has no clinical studies of its own.

What this molecule is

7-amino-acid synthetic fragment of Tβ4: Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln (positions 17–23) + modifications for solubility. ~888 Da.

Why it is studied

TB-500 = a synthetic fragment designed to reproduce the actin-polymerizing activity of Tβ4. Widely used by researchers in muscle, tendon, and joint injuries and post-surgical recovery. Popular in sports (WADA prohibited). There are NO clinical studies — all TB-500 data are taken from studies of full-length Tβ4.

How it works

Contains the LKKTETQ motif → G-actin binding → ↑cell migration. Partial angiogenic and anti-inflammatory effects (only via LKKTETQ, without the other Tβ4 domains).

Doses used in studies

In researchers' practice, 2–5 mg SC per week was used, divided into 2–3 injections, for a course of 4–6 weeks. The solution was prepared with 1–2 ml of bacteriostatic water.

Combined with in studies

• BPC-157 — synergy in tissue regeneration
• GHK-Cu — skin + blood vessels
• Ipamorelin — GH axis + regeneration

Level of evidence

Level D Cells and reviews. Only cell studies (in vitro), theory, or reviews. The earliest stage. No clinical studies of its own. Data are for full-length Tβ4.

Important to know

⚠️ WADA S2 prohibition (2022). All clinical data refer to full-length Tβ4 (43 aa), not to TB-500 (a fragment). Research only.

Studies in PubMed

1. A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin β4 in healthy Chinese volunteers. (J Cell Mol Med, 2021)
2. Thymosin beta4 and cardiac repair. (Ann N Y Acad Sci, 2010)
3. Progress on the Function and Application of Thymosin β4. (Front Endocrinol (Lausanne), 2021)
4. Thymosin β4 and prothymosin α promote cardiac regeneration post-ischaemic injury in mice. (Cardiovasc Res, 2023)
5. Utilizing Developmentally Essential Secreted Peptides Such as Thymosin Beta-4 to Remind the Adult Organs of Their Embryonic State-New Directions in Anti-Aging Regenerative Therapies. (Cells, 2021)
6. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. (Cornea, 2015)