Thymosin Beta-4
Also known as: TB-4, Tβ4, Timbetasin
At a glance
PeptiGuide dataset · reviewed Aug 2026
What it is
A 43-amino-acid actin-binding peptide with ophthalmic human studies and mainly preclinical systemic research.
Status
Clinical Trials
Typical dose
2.5–5mg
Researched for
Wound healing, cardiac repair, tissue regeneration
Trial progress
- PrePreclinical
- IPhase I
- IIPhase II
- IIIPhase III
- IVPhase IV
- FDAFDA approved
Phase III - Emerging human evidence with important limitations
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In plain language
- A 43-amino-acid also known as TB-4, Tβ4, and Timbetasin.
- The source identifies G-actin binding as a central biological feature.
- Human research cited by the source is concentrated in ophthalmic formulations, while systemic findings are largely .
- The source reports that it is not FDA approved.
- TB-500 is described as a related fragment, not the intact natural peptide.
How it's thought to work
Thymosin Beta-4 is described as binding monomeric G-actin, an interaction that can affect actin availability and cytoskeletal turnover. The supplied evidence associates this biology with cell migration, , inflammation-related signaling, and recruitment of endothelial cells, keratinocytes, and progenitor or stem cells at injured sites. It also reports hypotheses involving epicardial activation and cardiac-cell survival under low-oxygen conditions. Mechanistic observations alone do not demonstrate clinical benefit.
What the research shows
Where the research stands
The supplied source describes randomized, vehicle-controlled ophthalmic studies of RGN-259, a 0.1 % Tbeta4 eye-drop formulation, in dry eye and neurotrophic keratopathy. It reports a 317-patient phase 2/3 dry-eye trial with significant improvements in corneal staining and ocular discomfort, published in peer-reviewed journals. It characterizes cardiac results, including a porcine myocardial-infarction model, as and reports effects on cell engraftment, infarct size, and recovery; it also says the human cardiac program did not produce an approved drug. Wound-healing and hair-growth findings are described as mainly rodent data. The source does not identify completed pivotal trials establishing systemic benefit outside the eye program, and it reports no controlled human trial data for TB-500 itself.
What it shows
✓ Human studies
Emerging human evidence with important limitations
△ Limitations
Study protocols describe research and are not dosing recommendations.
Bottom line: The source reports that the Phase 3 dry-eye RGN-259/ARISE-3 study missed its primary endpoints while showing a secondary symptom benefit, and it notes a separate Phase 3 neurotrophic-keratopathy program. It also reports no FDA approval. Not FDA Approved
Typical dosing
CommunityCommunity dataset2.5–5 mg
2-3x weekly
Community-reported values only, not dosing guidance. The source identifies the full 43-amino-acid protein as distinct from a TB-500 fragment, says their uses are similar, describes its half-life as shorter, and notes frequent confusion between them. · Subcutaneous injection, topical for eye conditions
Research dosing
Study-specific protocolsHuman trials under way - protocols are study-specific
Timing & administration
Best time to take
Morning or split doses
Daily or every other day due to short half-life
Food recommendation
With or without food
Why this timing?
The source attributes protocol schedules to an approximately 2 hour half-life, notes that some protocols use multiple daily doses, and characterizes timing as flexible when consistency is maintained.
Possible side effects
Not everyone experiences these. Individual responses vary with dose, duration, and personal factors.
- Generally well-tolerated
- Injection site reactions
- Headache
- Fatigue
- May trigger histamine release
- Theoretical concern for cancer cell motility
- Contraindicated with active cancer
- Limited long-term safety data
Not everyone experiences side effects, and severity can vary by context, purity, route, and individual health factors.
Sources
Frequently asked questions
Sequence
Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser
One open dataset
Every fact on this page - doses, side effects, references - comes from the same PeptiGuide dataset that powers the Tracker, Compare, and the Lab.
Browse the datasetEducational resource, not medical advice. Talk to your clinician before acting on anything here.
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