Quick Facts
Plain-English Summary
TB-500 is a synthetic version of the naturally occurring peptide Thymosin Beta-4 (Tβ4), with research activity centred on its actin-binding domain (Ac-LKKTETQ, residues 17–23) which mediates cell migration and tissue repair. Thymosin Beta-4 is found in virtually all human and animal cells and plays a key role in actin sequestration, cell migration, and tissue repair. TB-500 is the term commonly used in research and biohacking communities for this fragment, though the underlying biology is derived from the full Tβ4 molecule. Research interest centres on its potential to accelerate wound healing, reduce inflammation, promote angiogenesis, and support cardiac and musculoskeletal recovery. Equine studies have provided some of the most detailed data on its tissue-repair properties.
The majority of TB-500's evidence base derives from animal studies — primarily rodent and equine models. No completed randomised controlled trials exist in healthy humans or athletes as of 2026, making extrapolation to human therapeutic use uncertain.
Human data is very limited. Early-phase trials conducted by Regenerx Biopharmaceuticals investigated Tβ4 for cardiac repair and venous ulcers, with mixed outcomes and no regulatory approval achieved. A phase II trial for dry eye syndrome showed modest positive results. The gap between compelling animal findings and validated human efficacy remains large.
Mechanism of Action
Proposed mechanisms below are derived from in vitro and rodent studies only. No mechanistic pathway has been validated in a controlled human study.
All mechanistic data is derived from in vitro or rodent studies. Applicability of these pathways in humans is not established.
Animal Data
| Model | Finding | ICPS Status |
|---|---|---|
| Murine wound healing | Tβ4 accelerated wound closure and promoted dermal cell migration. Hair follicle growth restoration also documented in multiple studies. Philp et al. 2003 ↗ | Preclinical |
| Rat myocardial infarction | Tβ4 promoted cardiomyocyte survival, reduced infarct size, and stimulated angiogenesis post-infarction. Epicardial progenitor mobilisation documented. Smart et al. 2007 ↗ | Preclinical |
| Equine tendon (performance horses) | Reduced tendon fibrosis and improved healing time in race horses. Widely used in performance horse racing; prohibited by WADA and major equine racing authorities. | Preclinical |
| Murine dermal scarring | Reduced dermal scarring and accelerated mucosal healing across multiple wound induction models. Consistent with actin-mediated cell migration mechanism. Philp et al. 2003 ↗ | Preclinical |
| Duchenne muscular dystrophy (mdx mice) | Tβ4 treatment improved cardiac and skeletal muscle function in dystrophin-deficient mouse model. Spurney et al. 2010 ↗ | Preclinical |
No finding from this section has been replicated in a controlled human trial. Animal-to-human translation for peptides is uncertain and cannot be assumed.
Human Trials
| Trial | Population | Status | ICPS Status |
|---|---|---|---|
| Phase II — Dry Eye Syndrome | Corneal epithelial defect patients; Tβ4 ophthalmic drops | — | Limited |
| Phase I/II — Cardiac Repair (Regenerx) | Post-MI patients; systemic Tβ4 administration | — | Incomplete |
| Phase II — Venous Ulcers (Regenerx) | Chronic venous ulcer patients; topical Tβ4 | — | Incomplete |
| All other indications (athletes, musculoskeletal) | — | — | No Data |
TB-500 has no FDA, EMA, or Health Canada–approved indications and no published Phase III trial data for any condition as of 2026.
Safety & Side Effects
No significant toxicity observed at typical research doses in animal studies. No mutagenicity, carcinogenicity, or organ toxicity reported in preclinical literature. Early-phase human trials reported a mild adverse effect profile consistent with animal data.
Pro-angiogenic mechanisms could theoretically accelerate tumour vascularisation in individuals with existing or undetected malignancy. This has not been documented in research settings but cannot be ruled out given limited human safety data.
- Injection site redness and mild soreness
- Transient fatigue in early days of use
- Mild headache (occasional)
- No pharmacovigilance database exists for TB-500
- Purity and sterile preparation are critical considerations
- Active or suspected malignancy
- Pregnancy or breastfeeding
- Immunosuppressive therapy
- Hormone-sensitive conditions
- Children and adolescents
TB-500 is not approved by the FDA, EMA, or Health Canada for any medical indication. It is classified as a research compound and is not legal for human therapeutic use in most jurisdictions. Procurement and use outside of registered clinical trials carries regulatory and unknown health risks.
References
Research disclaimer. CompoundProfile publishes summaries of available scientific literature for educational purposes only. This page does not constitute medical advice and should not be interpreted as an endorsement of TB-500 for any therapeutic use. Consult a licensed healthcare professional before considering any research compound. All evidence gradings reflect the state of published literature as of August 2026 and are assessed independently by ICPS.
Community Commentary
Selected discussion from r/Peptides · Curated for signal, not volume
6 weeks of TB-500 at 2mg twice weekly after a partial rotator cuff tear. MRI at week 8 showed significantly reduced inflammation and partial healing. My physio was surprised. Not claiming causation but the timeline was interesting.
Good n=1. The equine literature on tendon repair is actually solid. Human extrapolation is the question mark.
The cardiac data on Tβ4 is what got me interested. Smart et al in Nature showing epicardial progenitor mobilisation is legitimately exciting science. Whether TB-500 replicates this in healthy adults is unknown.
Used BPC-157 + TB-500 stack after ACL surgery. Hard to separate effects but recovery was ahead of schedule. Coach and surgeon both commented on it. Continuing TB-500 solo now.
The blend confounds attribution but the combined mechanism makes theoretical sense — BPC-157 for local healing, TB-500 for cell migration and angiogenesis.
Worth noting that TB-500 is widely used in racehorses and is on WADA's prohibited list. The equine data is probably the best real-world evidence we have outside controlled studies.