TB-500

Thymosin β4 · Tβ4 · TB4 · Ac-LKKTETQ fragment

Recovery, repair & tissue

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Summary

Class: Naturally occurring 43-amino-acid protein (Tβ4); TB-500 is typically a synthetic fragment or full-length copy
Mechanism: Binds actin to regulate cell movement, which supports wound closure, blood-vessel formation and reduced scarring
Routes studied: Eye drops and topical gel (human trials); injection (animal; community)
Dose range reported: Human trials: 0.1% eye drops; topical gel 0.01–0.1%. Community: 2–2.5 mg twice weekly for 4–6 weeks, then ~2 mg weekly. No validated systemic human dose.
Half-life: Not well characterised systemically; cleared from plasma within hours
Storage: Lyophilised: refrigerate. Reconstituted: refrigerate, use within ~4 weeks (community practice)
Regulatory status: Not approved for systemic use anywhere; ophthalmic/topical investigational

Doses are as reported in studies or by the community — never recommendations.

1What it is

Thymosin beta-4 is a small protein found in almost every cell in the body, at especially high levels in platelets and wound fluid. "TB-500" is the marketplace name for synthetic Tβ4 or, more often, a short fragment of it containing the actin-binding region. Which one is meant varies, and that matters when reading research.

The human trials have all used eye drops or topical gels, not injections.

2How it's thought to work

Actin sequestering. Holds single actin units and releases them where the cell needs to build structure, letting cells move.

Cell migration. Promotes migration of keratinocytes, endothelial and cardiac progenitor cells.

Angiogenesis. Encourages new blood-vessel growth.

Less scarring. Lower TGF-β1 and collagen deposition in models.

Proposed: binding actin monomers at the leading edge helps cells migrate into damaged tissue.Schematic — not to scale

3What the research shows

Dry eye disease

Randomised, placebo-controlled trials of 0.1% Tβ4 eye drops (ARISE-1–3) reported improvements in some endpoints, but inconsistent primary-endpoint success. [4]

Neurotrophic keratopathy

Phase 3 trials (SEER-1) reported higher complete-healing rates vs placebo in small numbers of patients. [4]

Chronic skin wounds

Phase 2 studies of topical gel in pressure ulcers, venous ulcers and EB reported wound-healing signals in small cohorts. [6]

Cardiac repair after heart attack

Mouse studies showed improved cardiac function after induced infarction. An injectable human trial did not progress. [2][3]

Soft-tissue, tendon and muscle injury

Animal models report improved healing. No human trials. This is the main community use. [1]

4Reported side effects and interactions

Literature-reported

Ophthalmic and topical formulations were well tolerated in trials. No systemic human safety data from controlled trials.

Community-reported

Head rush or lightheadedness shortly after injection, fatigue, headache, nausea; injection-site reactions.

Interactions. None established.

Markers researchers commonly monitor

Marker	Why it's watched
Any existing oncology screening	Pro-angiogenic activity — same caution as other angiogenic peptides

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Usually supplied in 5 mg or 10 mg vials. with , swirl gently.

Open in calculator, pre-loaded →

6Commonly studied alongside

BPC-157 →Often discussed as a pair for injury; no human study of the combination GHK-Cu →Repair context

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Not FDA-approved. Ophthalmic and topical forms investigational. Not permitted for compounding
European Union	Not authorised
United Kingdom	Not licensed
Australia	Not approved
South Africa	Not registered
Canada	Not authorised
Sport	Prohibited by WADA (S0)

8Open questions

Does the 17–23 fragment reproduce the full protein’s effects ?
Systemic pharmacokinetics and safety in humans — none published.
Any benefit for tendon or muscle injury in humans — untested.

9References

1Goldstein AL et al. (2005). Thymosin β4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med. PubMed · DOI
2Bock-Marquette I et al. (2004). Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration. Nature. PubMed · DOI
3Smart N et al. (2011). De novo cardiomyocytes from within the activated adult heart after injury. Nature. PubMed · DOI
4Sosne G et al. (2015). Thymosin β4 ophthalmic solution for dry eye. Clin Ophthalmol. PubMed
5Philp D et al. (2004). Thymosin β4 increases hair growth. FASEB J. PubMed
6Treadwell T et al. (2012). The regenerative peptide thymosin β4 accelerates dermal healing. Ann N Y Acad Sci. PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

10Community

forum threads →

community protocols include this →

Threads and protocols are visible to members. Joining is free.

Self-reported side effects Phase 2

Not enough data yet. 22 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

9 Oct 2026ARISE trial summary updated

10 Jun 2026Page published

Licensed CC BY-NC-SA 4.0. Found an error? Report it · Editorial standards — corrections are logged here.