Thymosin Beta-4

What people use it for

• Dry eye and corneal healing (clinical trials, as eye drops)
• Wound and heart repair (research)

What Thymosin Beta-4 does in the body

A 43-amino-acid protein found in most cells. It binds actin, helping cells move to and repair injured tissue, and has been linked to blood-vessel growth and reduced inflammation.

Strength of evidence

Limited to moderate: small human trials of eye-drop and gel formulations showed some benefits; injected use is not established.

Look up the evidence

• Reviews on PubMed: Summaries of the published research
• Clinical trials on PubMed: Published studies in people
• ClinicalTrials.gov: Registered trials, past and ongoing

Live searches of official databases. New to the terms? See the glossary.

Reported side effects & risks

• Eye irritation (eye drops)
• Injection-site reactions (injected, unofficial use)
• Unknown long-term effects of injection

Who should avoid it or take extra care

• Pregnant or breastfeeding
• Current or past cancer (it may promote cell growth; theoretical)
• Competitive athletes (prohibited by WADA)

Not a complete list. Check with a doctor or pharmacist about your own health and medicines.

Regulatory status

Not approved; prescription formulations are in clinical development. Prohibited in sport by WADA.

How it's taken

Route: Eye drops or gel in trials; injection in unofficial use

How long it lasts (half-life): Short; not well established

Storage

Unreconstituted (powder) vials are usually kept refrigerated or frozen and away from light. Once mixed with bacteriostatic water, keep refrigerated and do not freeze; follow the supplier's stated beyond-use date.