Overview

A rare case where a research peptide has real clinical trial data — but for the eye, in a topical formulation, using the full-length protein. The injectable fragment sold for tendon and muscle repair is a different product with a different evidence base, which is to say almost none.

Not approved for human use anywhereNo approval anywhere for human use. Sold under research-use labelling. Ophthalmic Tβ4 remains investigational. Injectable TB-500 is unapproved and not lawfully sold for human use.

At a glance

Regulatory status	Full-length Tβ4 has reached phase 2/3 trials for dry eye and corneal wounds. The injectable TB-500 fragment sold to consumers is unapproved. WADA-prohibited.
Drug class	Thymosin beta-4 is a 43-amino-acid actin-sequestering protein; TB-500 is a synthetic active fragment
Route	Subcutaneous (research); topical/ophthalmic in trials
Half-life	Full Tβ4 several hours; fragment not well characterised
Evidence rating	2/5 Limited Evidence rating 2 out of 5: Limited Preclinical work plus scattered human reports, uncontrolled use, or negative trials.
Studied in	Phase 2/3 ophthalmic trials for dry eye disease and neurotrophic keratopathy; phase 2 dermal wound trials in venous stasis and epidermolysis bullosa; preclinical cardiac and CNS injury models.

How it works

Thymosin beta-4 sequesters G-actin and regulates cytoskeletal dynamics, promoting cell migration, angiogenesis, and downregulation of inflammatory mediators. It also upregulates laminin-5 and matrix metalloproteinases involved in tissue remodelling.

Evidence base

Rated 2 of 5 — Limited. Preclinical work plus scattered human reports, uncontrolled use, or negative trials.

Human evidence exists but is confined to topical ophthalmic use of the full protein.
Do not transfer that evidence to injectable fragment use — the two are not equivalent.

Benefits & potential uses

Bars indicate how well each claim is supported: three = strong human evidence, two = moderate, one = preliminary or preclinical.

Corneal wound healing evidence in humans Moderate evidence

Ophthalmic trials of full-length Tβ4 reported improved corneal healing and dry-eye symptom scores — genuine randomized human data.
Cell migration and angiogenesis Moderate evidence

Well-characterised molecular biology supporting a role in wound repair.
Anti-inflammatory and antifibrotic signals Preliminary

Preclinical models show reduced scarring and inflammatory mediator expression.
Cardiac repair in animal models Preliminary

Promotes epicardial progenitor activation after myocardial infarction in rodents.

Risks, cons & cautions

Bars indicate seriousness: three = serious or common, two = moderate, one = minor.

Injectable fragment is untested in humans Serious

The systemic TB-500 sold online has no clinical trial support for musculoskeletal healing.
Angiogenesis and tumour concern Serious

Tβ4 is upregulated in several cancers and promotes tumour cell migration in laboratory models. Systemic chronic use in anyone with cancer risk is a real concern.
No established systemic dosing or safety Serious

Ophthalmic trials say nothing about the safety of injecting it for months.
Unregulated supply Serious

Research-chemical market quality problems apply.
WADA prohibited Moderate evidence

Athletes have been sanctioned for TB-500.

Who should avoid it

Cancer history or active malignancy
Pregnancy
Tested athletes

If used under medical supervision, monitor

No validated monitoring for systemic use

Commonly confused with

These mix-ups cause real harm — two products sold under one name, or two molecules whose effects run in opposite directions.

BPC-157 Research Use Only Evidence 1/5

Commonly stacked. Both lack human trial evidence for tendon and muscle repair.

Compare side by side

Regulatory & legal status

Ophthalmic Tβ4 remains investigational. Injectable TB-500 is unapproved and not lawfully sold for human use.

Infographic

TB-500 / Thymosin Beta-4 — benefits & risks at a glance Download SVG

Where to read further

We link to live literature searches rather than a frozen citation list, so you always see current results — including anything published after our last review.

wound healingtendoneyeangiogenesisresearch chemical

Related peptides in Healing & Tissue Repair

Terms used on this page

Tendon Structure: Tendon is a hierarchical collagen composite transmitting muscle force to bone, built from fibrils and fascicles held in a sliding matrix and populated sparsely by tenocytes.
Matrix Metalloproteinase (MMP): Matrix metalloproteinases are zinc-dependent enzymes that cut extracellular matrix proteins, and their balance against tissue inhibitors decides whether tissue remodels or degrades.
Receptor Downregulation: Receptor downregulation is a sustained reduction in the number of receptors a cell presents, produced by prolonged agonist exposure and reversed only by resynthesis over hours to days.
Angiogenesis: Angiogenesis is the sprouting of new capillaries from existing vessels, the process that supplies oxygen and nutrients to a healing wound or a growing tumour alike.
Preclinical Study and Animal Model: Preclinical studies are the laboratory, cell and animal experiments done before any human exposure, establishing mechanism, target engagement and the toxicology package that permits a first trial.

This page is educational information, not medical advice. It cannot account for your medical history, medications, or risk factors. Do not start, stop or change any treatment based on it. Speak to a qualified healthcare professional who knows your case.