Gathering the record
Relay is organizing the evidence and source boundaries.
Endogenous 43-amino-acid actin-sequestering peptide
A naturally occurring peptide studied for tissue repair, including eye and heart conditions.
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
Why people look into it, what studies found, and what is still unknown.
Educational information only. Evidence reviewed through July 25, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Each label shows how much evidence supports that question.
What studies show
Multiple controlled studies exist, but each is limited: short Phase 1 IV safety studies, a nine-patient ophthalmic Phase 2 trial, and a 96-person STEMI trial with a timing-dependent subgroup result but no significant overall infarct-area difference.
TB-500 contains only an N-acetylated seven-amino-acid segment from residues 17-23.
Human programs include short IV safety studies, a very small ophthalmic dry-eye trial, wound programs, and a 96-person recombinant-product cardiac trial.
Two early studies reported no dose-limiting toxicity or serious adverse events over short observation periods.
A nine-patient Phase 2 study reported improvements after 0.1% thymosin beta-4 eye drops.
A smaller infarct area was reported in the subgroup first treated within eight hours, while the overall 96-person comparison was not significant.
Its human evidence comes from research formulations and trial protocols rather than an approved label.
Risks & unknowns
Short intravenous studies support tolerability and pharmacokinetic characterization, not broad clinical benefit.
Controlled human evidenceSmall samples and short follow-up cannot resolve rare events, long-term safety, effectiveness, or other routes.
Open sourceThe available information does not reliably show how often particular side effects occur.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
Relay has not verified a compound-specific warning summary for this profile.
Evidence boundaryInvestigational; no FDA-approved thymosin beta-4 product was located. WADA prohibits thymosin beta-4 and its derivatives. Which formulation-specific findings replicate in larger trials, long-term safety, whether any benefit generalizes beyond the studied route and condition, and how investigational products differ.
This profile does not contain verified, product-specific emergency instructions.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
IV · Into a vein
Amounts reported in a human study. A studied amount is not automatically an approved dose or a recommendation for an individual.
Healthy volunteers received a defined recombinant product in single- and multiple-dose safety studies.
| Stage / period | Amount in source | Frequency |
|---|---|---|
| 10 treatment days | 0.5, 2, or 5 micrograms/kg groups | Once daily in the multiple-dose study |
Separate single-dose cohorts tested 0.05–25 micrograms/kg. This reference applies to NL005, not TB-500 fragments, topical products, or a general recovery injection schedule.
Recombinant human thymosin beta-4 · first-in-human NL005 study Primary article · Methods / interventionThis reference checked Oct 20, 2026. The full-profile review date is shown at the top.This source does not establish a mixing volume or storage period for independently sourced powder. Use formulation-specific instructions; the study amount alone is not a reconstitution recipe.
Concentration = total mass ÷ final volume. The calculator performs user-entered math; it does not choose a dose or diluent.
Open concentration calculatorStarting dose: the amount used at the beginning of the named label schedule or trial.
Maintenance: the ongoing amount described by that product label.
Trial target: the amount assigned to a study group. Different groups may stop increasing at different targets.
A randomized controlled study investigated a recombinant full-length thymosin beta-4 product after reperfusion treatment for acute heart attack.
Population: Adults with acute ST-segment elevation myocardial infarction after reperfusion
Design: Randomized, double-blind, placebo-controlled trial after PCI for acute STEMI
Mechanisms
Full-length thymosin beta-4 sequesters globular actin and has been studied in cell migration, wound repair, ophthalmic disease, and cardiac injury. Controlled human evidence spans short IV safety/PK studies, a very small topical-eye Phase 2 trial, and a 96-person recombinant-product STEMI trial whose overall infarct-area comparison was not significant.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Research reference
A reference for the studies, populations, and routes behind this profile.
Controlled human studies exist for full-length synthetic or recombinant products, but they remain small, formulation-specific, and outcome-limited.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
IV exposure and short-term tolerability are documented; clinical benefit remains preliminary, mixed, or confined to very small studies.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The overall 96-person infarct-area comparison was not significant; the positive signal depended on treatment timing and subgroup interpretation. This product and study do not establish systemic repair effects or any finding for the seven-amino-acid TB-500 fragment. Amounts shown describe cited research exposure—not a dosage recommendation.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized, double-blind, placebo-controlled trial after PCI for acute STEMI
Adults with acute ST-segment elevation myocardial infarction after reperfusion
The overall infarct-area difference was not significant. A reported subgroup first treated within eight hours after PCI showed a smaller infarcted area at 90 days.
Study administration: Protocol-defined recombinant human thymosin beta-4 or placebo after PCI
Limitations: The positive finding depended on treatment timing and subgroup interpretation, while the overall 96-person comparison was not significant. Replication is needed and the study is not evidence for TB-500.
Randomized, double-blind, placebo-controlled single- and multiple-ascending-dose study
Healthy Chinese volunteers
Reported adverse events were mild to moderate, with no dose-limiting toxicity or serious adverse events. Exposure increased with dose and no obvious accumulation was reported.
Study administration: Protocol-defined intravenous recombinant human thymosin beta-4 NL005 or placebo
Limitations: Short Phase 1 study in healthy volunteers. It does not establish clinical efficacy, long-term safety, non-IV use, or any result for TB-500.
Multicenter, randomized, double-masked, vehicle-controlled ophthalmic trial
Nine patients with severe dry eye, including graft-versus-host-associated disease
The small trial reported improvements in discomfort and corneal staining at several time points, including day 56.
Study administration: RGN-259 0.1% thymosin beta-4 eye drops or vehicle under the trial protocol
Limitations: Only nine patients and 18 eyes at two sites. This topical eye formulation does not establish systemic effects, injection benefits, or TB-500 activity.
Randomized, placebo-controlled, single- and multiple-ascending-dose study
Healthy volunteers in four cohorts
Adverse events were infrequent and mild or moderate, with no dose-limiting toxicities or serious adverse events reported during the short study. Exposure increased with dose.
Study administration: Protocol-defined intravenous synthetic full-length thymosin beta-4 or placebo
Limitations: Small, short safety and PK study in healthy volunteers. It did not test healing, recovery, or long-term benefit and is not evidence for TB-500.
Community
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Every structured report adds useful context about research setup, outcomes, and unwanted effects as the community dataset grows.
Publicly anonymous by default. Your account keeps reports editable and helps reduce duplicate submissions.Sources
2026-07-21
2026-01-01
2025-12-31 · PMID 41229390 · NCT05485818 · DOI 10.1093/cvr/cvaf223
2021-08-02 · PMID 34346165 · DOI 10.1111/jcmm.16693
2015-05-01 · PMID 25826322 · NCT01393132 · DOI 10.1097/ICO.0000000000000379
2012-10-01 · PMID 23050815 · DOI 10.1111/j.1749-6632.2012.06717.x
2010-04-01 · PMID 20536472 · DOI 10.1111/j.1749-6632.2010.05474.x