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Thymosin Beta-4

Also known as Tβ4, TB4, thymosin beta 4.

Best known for The full protein that TB-500 is a fragment of

Evidence★★☆☆☆

Safety dataPoorly characterised

Route Injectable · topical (trials)

United StatesNot approved

AustraliaAppendix D cl.5: possession without authority illegal (named individually)

as at 16 September 2026

What it is

Thymosin Beta-4 is a 43-amino-acid protein found in almost all human cells, central to cell migration and tissue repair. It has reached human trials in dry eye disease and certain wounds, and it is not approved. TB-500 is a synthetic fragment of it. The two are often treated as interchangeable, but they are different molecules.

What the full entry covers

The book carries the rest of this entry:

Where the research stands, with every claim cited
What people commonly ask, and what the research shows so far
Dosing in four labelled bands, described and not recommended
Side effects, serious risks, cautions and interactions
Questions to discuss with your doctor
How it compares with TB-500, BPC-157, Thymosin Beta-4 Fragments, GHK-Cu

Related entries

TB-500The other half of the "Wolverine Stack" · Evidence ★★☆☆☆
BPC-157Tendon, joint and gut repair · Evidence ★★☆☆☆
Thymosin Beta-4 FragmentsSub-fragments used as alternatives to TB-500 · Evidence ★☆☆☆☆
GHK-CuSkin renewal and collagen support · Evidence ★★☆☆☆

A certificate of analysis tells you what is in a vial. The evidence rating above tells you whether the compound has been shown to work in humans. Neither answers the other's question. How to read a certificate of analysis.

This page describes what is known and not known about Thymosin Beta-4. It is not medical advice and not a recommendation to use it.