What is TB-500 (Thymosin Beta-4 fragment)?

A synthetic fragment of thymosin beta-4 (43-aa parent, too large for oral use).

TB-500 (Thymosin Beta-4 fragment) in the library · Healing & Repair Peptides · Human Trials · What are peptides?

16 registered trials · 9 indexed papers · 150 human / 261 animal studies

From the PeptideWhiz library entry. "As described" sections summarize claims made in the sources; they are not PeptideWhiz endorsements.

What it is

A synthetic fragment of thymosin beta-4 (43-aa parent, too large for oral use). Called the "construction crew" that moves repair cells to the injury.

Mechanism (as described)

  • Cell movement: binds actin monomers (sequesters them), so cells stay mobile; the master regulator of cell migration.
  • Repair: draws endothelial and stem cells; promotes organized, mature vessel growth and collagen.
  • Scarring: anti-inflammatory and anti-fibrotic (heart and kidney).
  • Heart: improves heart function and blood flow to ischemic tissue after infarction; raises mitochondrial biogenesis.
  • Brain: crosses the blood-brain barrier. Neurogenesis and less brain inflammation after TBI; functional recovery after stroke.
  • Eye: corneal repair.

Additional points (as described)

  • Organ uses discussed: heart after infarction (fibrosis), athlete's heart, kidney and liver fibrosis, brain (crosses the BBB; TBI, stroke), lung fibrosis (with NAC), cornea.
  • It's the fragment discussed. Full-length thymosin β4 is costly and often fake.
  • Pairs: BPC-157 (VEGF path) + TB-500 (actin path) cover the main repair routes; GHK-Cu, tesamorelin and KPV are described as additions for a full repair stack.

FDA Compounding Panel (July 2026)

At its July 23-24, 2026 meeting, the FDA Pharmacy Compounding Advisory Committee recommended adding TB-500 (free base and acetate) to the Section 503A bulks list, for the uses FDA reviewed (wound healing). FDA's own briefing documents had proposed not adding it.

  • The vote is advisory and non-binding. It is not FDA approval, and it does not by itself allow pharmacies to compound TB-500. FDA would have to finish rulemaking to change the final list (21 CFR 216.23), which included no peptides as of October 2026.
  • Reported tally (yes-no-abstain): 8-6-1, as reported in law-firm meeting reports. FDA had not posted official minutes or vote results when checked on October 19, 2026.
  • FDA: July 23-24, 2026 PCAC meeting materials (substances under consideration)
  • FDA: July 23-24, 2026 PCAC final agenda
  • eCFR: 21 CFR 216.23, the final 503A bulks list

Registered human trials (16)

TrialPhaseStatusYearEnrolled
Recombinant Human Thymosin Beta 4 for Injection(NL005) for Acute Myocardial InfarctionPhase 2not yet recruiting2026189
TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVDPhase 1/Phase 2recruiting202680
Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of NK: SEER-2Phase 3recruiting202370
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3Phase 3completed2019700
Evaluation of the Safety and Efficacy Study of RGN-137 Topical Gel for Junctional and Dystrophic Epidermolysis BullosaPhase 2terminated20194
A Study of the Safety and Efficacy of Injectable Thymosin Beta 4 for Treating Acute Myocardial InfarctionPhase 2withdrawn2019
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome : ARISE-2Phase 3completed2016601
Assessment of the Safety and Efficacy Study of RGN-259 Ophthalmic Solutions for Neurotrophic Keratopathy : SEER-1Phase 3terminated201518
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-1Phase 2/Phase 3completed2015317
Comparative Study of Thymosin Beta 4 Eye Drops vs. Vehicle in the Treatment of Severe Dry EyePhase 2completed20119
Safety and Efficacy of Thymosin Beta 4 Ophthalmic Solution in Patients With Dry EyePhase 2completed201172
A Phase 1 Safety Study of the Intravenous Administration of Thymosin Beta in Healthy VolunteersPhase 1withdrawn2008
A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal WoundsPhase 2terminated200712
A Phase 2 Study on Effect of Thymosin Beta 4 on Wound Healing in Patients With Epidermolysis BullosaPhase 2terminated200630
Study of Thymosin Beta 4 in Patients With Venous Stasis UlcersPhase 2completed200672
Study of Thymosin Beta 4 in Patients With Pressure UlcersPhase 2completed200672

Peer-reviewed studies (9)

PaperAuthorsJournalYearType
0.1% RGN-259 (Thymosin ß4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical TrialSosne G et al.International journal of molecular sciences2022Randomized Controlled Trial
Association between Thymosin beta-4, acute kidney injury, and mortality in patients with sepsis: An observational cohort studyZhang J et al.International immunopharmacology2021Observational Study
A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin β4 in healthy Chinese volunteersWang X et al.Journal of cellular and molecular medicine2021Randomized Controlled Trial
Safety and efficacy of autologous thymosin β4 pre-treated endothelial progenitor cell transplantation in patients with acute ST segment elevation myocardial infarction: A pilot studyZhu J et al.Cytotherapy2016Randomized Controlled Trial
Increases in plasma Tβ4 after intracardiac cell therapy in chronic ischemic heart failure is associated with symptomatic improvementChoudry FA et al.Regenerative medicine2015Randomized Controlled Trial
Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trialSosne G et al.Cornea2015Randomized Controlled Trial
A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteersRuff D et al.Annals of the New York Academy of Sciences2010Randomized Controlled Trial
The effect of thymosin treatment of venous ulcersGuarnera G et al.Annals of the New York Academy of Sciences2010Randomized Controlled Trial
Thymosin beta-4 and venous ulcers: clinical remarks on a European prospective, randomized study on safety, tolerability, and enhancement on healingGuarnera G et al.Annals of the New York Academy of Sciences2007Randomized Controlled Trial

More cited research

Conditions researched

Related compounds

FAQ

What is TB-500 (Thymosin Beta-4 fragment)?

A synthetic fragment of thymosin beta-4 (43-aa parent, too large for oral use).

How many registered human trials study TB-500 (Thymosin Beta-4 fragment)?

The PeptideWhiz trial index lists 16 registered trials for TB-500 (Thymosin Beta-4 fragment), the most recent from 2026.

How much published research exists on TB-500 (Thymosin Beta-4 fragment)?

The PeptideWhiz paper index links 9 PubMed papers to TB-500 (Thymosin Beta-4 fragment); by study type, 150 human and 261 animal studies.

Which conditions is TB-500 (Thymosin Beta-4 fragment) researched for?

Tendon, ligament, muscle & joint injuries (incl. athletes), Heart repair: after heart attack, heart failure & enlarged heart, Ankylosing spondylitis, Rheumatoid arthritis, Multiple sclerosis, Lyme disease & chronic infections, Lung health, asthma & COPD, Kidney protection (CKD, diabetic kidney, lupus kidney), Concussion, traumatic brain injury & stroke recovery, Osteoarthritis, cartilage loss & avoiding joint replacement, High-demand jobs: military, fire, police, EMT (and combat-sport athletes), Anti-aging & longevity, Atherosclerosis, cardiovascular disease & high blood pressure, Chronic pain: fibromyalgia & CRPS, Parkinson's disease, Skin, hair loss, wounds & mast-cell/histamine reactivity, POTS and dysautonomia, Carpal tunnel, Bell's palsy, Varicose veins, Lipedema, Chronic and systemic inflammation, Eyes: macular degeneration & retinal health, High cholesterol and statins, Muscle gain, sarcopenia & building muscle after 40, Immune system (general), Insulin resistance, prediabetes & type 2 diabetes, Lupus (SLE).

Research and education only. Not medical advice. No dosing guidance. Data: ClinicalTrials.gov registry and PubMed via the PeptideWhiz index (204,289 studies).

Reported dosing ranges from research