TB-500
Research OnlyA synthetic fragment of thymosin beta-4 marketed for tissue repair. While the parent compound has Phase 3 clinical research (RGN-259), TB-500 specifically has no published human data.
Thymosin Beta-4 Fragment · TB4-FRAG · TMSB4X
8 human studies
- Preclinical
- 59%
- Clinical
- 24%
Based on 34 cited sources
clinically demonstrated · very-low confidence
Demonstrated effect magnitude — not a recommendation or safety claim.
Research Depth 46: no direct human OR direct fragment data — TB-500 is the LKKTETQ fragment, while all human evidence is on full-length thymosin beta-4 (RGN-259), so 1A/1C/1D are heavily discounted for GRADE indirectness (wrong molecule, and the strongest human outcome is corneal, not the marketed tissue-repair use); RGN-259 reached a small placebo-controlled Phase 3 RCT (36613994, n=18, primary endpoint missed at p=0.066) with the confirmatory Phase 3 (SEER-2) still ongoing (1B 11, 1C 5, 1D 3); 1E credited 9 for an extensive, independently-replicated Tb4 preclinical program across species (wound 10469335, cardiac 15565145/25015963, fibrosis 23320620, cornea 17254567). Mechanism 73: actin-sequestration target is binding+functional confirmed, ILK/PINCH/Akt complex characterized (15565145), downstream pathways largely mapped, in-vivo dose-response in some models (2A 30 / 2B 22 / 2C 12 / 2D 9). Plausibility 69: mechanism->surrogate (re-epithelialization, infarct size) solid and fully coherent with repair biology (20179146), but surrogate->clinical link is weak/mixed (failed EU Phase 3) and marketed claims span many systems (3A 22 / 3B 24 / 3C 14 / 3D 9). Global Coverage 76: robustly replicated across independent groups in the USA, UK, Germany, Italy and China with >100 Tb4 studies; only clinical-trial-stage governance recognition for the parent, none for the fragment (4A 27 / 4B 22 / 4C 22 / 4D 5). Community Experience 71: broad, multi-year athletic/injury- recovery use (frequently paired with BPC-157), broadly consistent themes, only minor adverse reports (5A 22 / 5B 24 / 5C 14 / 5D 11). Effectiveness basis clinical but VERY LOW confidence: the only quantified human efficacy estimate is RGN-259 corneal healing (6/10 vs 1/8, p=0.066, a strong trend that did NOT replicate in the failed EU Phase 3) — and it is for the parent molecule in a different indication, not the TB-500 fragment, which has zero human efficacy data.
The proposed mechanisms are largely extrapolated from thymosin beta-4 research, not TB-500 specifically.
How It Works (Simplified)
TB-500 is a fragment of thymosin beta-4 that acts as a “repair signal” through several pathways:
Binds G-actin to regulate cytoskeletal dynamics, making cells more flexible and able to move to injury sites.
Promotes keratinocyte and fibroblast migration to wound sites, increasing re-epithelialization by 42-61% in animal models.
Activates ILK-Akt pathway promoting cell survival, particularly cardioprotective in myocardial injury models.
Suppresses NF-kB and modulates microRNA-146a pathway, reducing excessive inflammatory responses and fibrosis.
Key Research: Bock-Marquette et al. (Nature, 2004) demonstrated ILK-Akt activation in cardiac tissue. PMID:15565145
Important Limitations
- All research is on parent compound (thymosin beta-4), not TB-500 specifically
- TB-500 is a fragment that may not replicate full Tb4 effects
- No human clinical trials have studied TB-500 directly
- RGN-259 (full Tb4) Phase 3 trial for corneal healing (neurotrophic keratopathy, n=18) showed a strong trend but missed statistical significance on its primary endpoint; a confirmatory Phase 3 is ongoing
- Translation from preclinical to human outcomes is unconfirmed
Reported positives
- Reduced inflammation and faster tissue repair widely reported
- Improved flexibility and reduced stiffness after injuries
- Synergistic effects when combined with BPC-157
- Systemic healing effects noted across multiple injury types
Reported negatives
- Slower onset than BPC-157 — effects take longer to notice
- Headaches reported by some users
- Fatigue and lethargy during initial use
- Product purity concerns from unregulated suppliers
“Frequently paired with BPC-157. Popular in athletic and injury recovery communities.”
Self-reported, unverified accounts — not clinical evidence and no substitute for the cited research. Anecdotes are prone to selection bias and placebo effects.
| NCT ID | Title | Peptide | Phase | Status | Completion |
|---|---|---|---|---|---|
| NCT00832091 | Thymosin Beta 4 in Venous Stasis Ulcers Venous Stasis Ulcers | TB-500 | Phase 2 | Completed | Jan 2009 |
| NCT00408083 | Thymosin Beta 4 Eye Drops for Dry Eye | TB-500 | Phase 2 | Completed | - |
| NCT01387347 | Thymosin Beta 4 Dry Eye Controlled Adverse Environment Dry Eye Syndrome, Dry Eye | TB-500 | Phase 2 | Completed | Oct 2011 |
| NCT02016131 | SEER-1: RGN-259 for Neurotrophic Keratopathy | TB-500 | Phase 3 | Completed | - |
| NCT03967665 | SEER-2: RGN-259 for Neurotrophic Keratopathy | TB-500 | Phase 3 | Recruiting | - |
| EUCTR2018-002231-14 | SEER-3: RGN-259 for Neurotrophic Keratopathy | TB-500 | Phase 3 | Failed primary endpoint | - |
| NCT01311518 | RGN-352 for Acute Myocardial Infarction Acute Myocardial Infarction, ST Elevation Myocardial Infarction +1 more | TB-500 | Phase 2 | Withdrawn | Jul 2020 |
| ACTRN12610000287033 | Tβ4 in Horse Tendon Injuries | TB-500 | Phase Veterinary | Completed | - |
| NCT07586865 | Recombinant Human Thymosin Beta 4 for Injection(NL005) for Acute Myocardial Infarction Acute Myocardial Infarction (AMI), Acute Myocardial Infarction of Anterior Wall +3 more | TB-500 | Phase 2 | Not yet recruiting | Aug 2027 |
| NCT07487363 | TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD Atherosclerotic Cardiovascular Diseases, Endothelial Dysfunction | TB-500 | Phase 1/2 | Recruiting | Feb 2027 |
| NCT05555589 | Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of NK: SEER-2 Neurotrophic Keratopathy | TB-500 | Phase 3 | Recruiting | Apr 2026 |
| NCT05984134 | Efficacy and Safety Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction Acute Myocardial Infarction | TB-500 | Phase 2 | Completed | May 2023 |
| NCT05485818 | Safety and Efficacy Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction.Infarction Acute Myocardial Infarction | TB-500 | Phase 2 | Completed | Sep 2021 |
| NCT03937882 | Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3 Dry Eye Syndromes, Dry Eye | TB-500 | Phase 3 | Completed | Nov 2020 |
| NCT04555850 | A Phase 1b Study of Thymosin Beta 4 in Healthy Volunteers Healthy | TB-500 | Phase 1 | Completed | Feb 2019 |
| NCT04555824 | A Phase 1a Study of Thymosin Beta 4 in Healthy Volunteers Healthy | TB-500 | Phase 1 | Completed | Feb 2018 |
| NCT02974907 | Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome : ARISE-2 Dry Eye Syndrome | TB-500 | Phase 3 | Completed | Sep 2017 |
| NCT02600429 | Assessment of the Safety and Efficacy Study of RGN-259 Ophthalmic Solutions for Neurotrophic Keratopathy : SEER-1 Neurotrophic Keratopathy | TB-500 | Phase 3 | Terminated | Nov 2019 |
| NCT02597803 | Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-1 Dry Eye Syndrome | TB-500 | Phase 2/3 | Completed | Jun 2016 |
| NCT02668055 | Slow-release Tb4 Collagen and Chitosan Porous Sponge Scaffolds Skin Substitute Treatment is Difficult to Heal Wounds Wounds | TB-500 | Phase 1 | Completed | Dec 2015 |
| NCT01393132 | Comparative Study of Thymosin Beta 4 Eye Drops vs. Vehicle in the Treatment of Severe Dry Eye Dry Eye, Sjogren's Syndrome +1 more | TB-500 | Phase 2 | Completed | Dec 2012 |
| NCT00743769 | A Phase 1 Safety Study of the Intravenous Administration of Thymosin Beta in Healthy Volunteers Myocardial Infarction, Myocardial Ischemia | TB-500 | Phase 1 | Withdrawn | Jan 2017 |
| NCT00598871 | A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal Wounds Diabetes | TB-500 | Phase 2 | Terminated | Feb 2009 |
| NCT00382174 | Study of Thymosin Beta 4 in Patients With Pressure Ulcers Pressure Ulcers | TB-500 | Phase 2 | Completed | Dec 2008 |
| NCT00311766 | A Phase 2 Study on Effect of Thymosin Beta 4 on Wound Healing in Patients With Epidermolysis Bullosa Epidermolysis Bullosa | TB-500 | Phase 2 | Terminated | Jul 2010 |
Thymosin Beta 4 Dry Eye Controlled Adverse Environment
SEER-3: RGN-259 for Neurotrophic Keratopathy
Recombinant Human Thymosin Beta 4 for Injection(NL005) for Acute Myocardial Infarction
TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD
Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of NK: SEER-2
Efficacy and Safety Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction
Safety and Efficacy Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction.Infarction
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3
A Phase 1b Study of Thymosin Beta 4 in Healthy Volunteers
A Phase 1a Study of Thymosin Beta 4 in Healthy Volunteers
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome : ARISE-2
Assessment of the Safety and Efficacy Study of RGN-259 Ophthalmic Solutions for Neurotrophic Keratopathy : SEER-1
Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-1
Slow-release Tb4 Collagen and Chitosan Porous Sponge Scaffolds Skin Substitute Treatment is Difficult to Heal Wounds
Comparative Study of Thymosin Beta 4 Eye Drops vs. Vehicle in the Treatment of Severe Dry Eye
A Phase 1 Safety Study of the Intravenous Administration of Thymosin Beta in Healthy Volunteers
A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal Wounds
Study of Thymosin Beta 4 in Patients With Pressure Ulcers
A Phase 2 Study on Effect of Thymosin Beta 4 on Wound Healing in Patients With Epidermolysis Bullosa
Based on parent compound (Thymosin Beta-4) research: Initial effects on cell migration and cytoskeletal remodeling may begin. Equine studies showed early anti-inflammatory response. No TB-500 specific human data exists.
PMID:22074294Animal studies with Thymosin Beta-4 show wound healing improvements by 2-4 weeks. Corneal healing studies demonstrated accelerated epithelialization within this timeframe.
PMID:10469335Preclinical cardiac models showed improved function by 4-8 weeks post-MI. Neurological studies indicated ongoing neuroregeneration and oligodendrogenesis in this period.
PMID:15565145Long-term effects in animal models suggest sustained tissue repair. Phase 3 RGN-259 ophthalmology trials showed healing at 28 days for corneal conditions. Human timeline for TB-500 specifically is unknown.
PMID:36613994Research-based observations
This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.
Good Signs (6 indicators)
Warning Signs (5 indicators)
Bad Signs (7 indicators)
For Research Evaluation Only
These quality indicators are general guidelines based on typical peptide characteristics. Professional laboratory testing (HPLC, mass spectrometry) provides definitive quality verification. This checklist is for initial visual evaluation only.
BPC-157
SynergisticFrequently combined for tissue repair research. TB-500's actin-sequestering and cell migration effects may complement BPC-157's cytoprotective and angiogenic pathways. No clinical combination studies exist.
GHK-Cu
CompatibleBoth promote wound healing through different mechanisms. TB-500 modulates actin dynamics while GHK-Cu activates copper-dependent signaling. Theoretically complementary.
Thymosin-Alpha-1
CompatibleDifferent thymosin family members with distinct functions. Thymosin Alpha-1 focuses on immune modulation while TB-500 (Thymosin Beta-4 fragment) targets tissue repair.
Ipamorelin
CompatibleNon-overlapping mechanisms. GH secretagogues like ipamorelin may theoretically support tissue repair processes. No direct interaction data.
CJC-1295
CompatibleGHRH analog with different target system. May complement tissue repair through GH/IGF-1 pathway. No known contraindications.
Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.
Key Studies Cited
Full reference list available on request. All citations link to PubMed for verification.
This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength ratings follow a modified GRADE approach.
For complete methodology details, see our Methodology page.
Important Disclaimer
This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.
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