TB-500 — Research Dossier
Evidence grading
First isolated
1960s
Thymosin beta-4 from calf thymus · Goldstein et al.
Human trial stage
Phase 2–3
Ophthalmic / dermal indications only
Musculoskeletal trials
0
No completed Phase 2/3 for systemic use
Regulatory approvals
None
Not approved in any jurisdiction
TB-500 is the synthetic counterpart of thymosin beta-4, a naturally occurring repair peptide. Its evidence base is unusual: a well-characterised molecular biology and some late-stage human trials — but those trials are in eye and skin indications, not the musculoskeletal uses the compound is best known for.
Thymosin beta-4 (Tβ4) is an endogenous, well-characterised actin-sequestering peptide first isolated in the 1960s by Goldstein and colleagues at George Washington University. It is among the first peptides released at a wound site and is studied for roles in cell migration, angiogenesis, tissue repair and inflammation regulation.
"TB-500" is the synthetic version. Vendor-grade TB-500 is not the same material as the pharmaceutical-grade Tβ4 used in clinical trials.
“The completed human evidence is concentrated in topical ophthalmic and dermal indications. The systemic musculoskeletal use the compound is most associated with has not been established in completed Phase 2 or Phase 3 human trials.”
— Nexyra Journal · Dossier No. 02
The evidence base
The basic-science foundation is comparatively strong, with multiple independent laboratories contributing. Preclinical wound-healing work includes Malinda et al. (1999, dermal) and Philp et al. (2003, corneal), among others.
The corneal findings led to the most advanced clinical programme: RegeneRx Biopharmaceuticals developed pharmaceutical-grade Tβ4 as RGN-259 — a topical ophthalmic formulation for dry-eye disease and corneal injury. This reached Phase 3 in the ARISE dry-eye trials, with mixed results that did not fully meet the endpoints required for approval.
Related programmes studied topical Tβ4 for dermal wounds and an intravenous formulation (RGN-352) explored for cardiac repair at an early stage.
What the human data does — and does not — cover
The completed human evidence is concentrated in topical ophthalmic and dermal indications, and remains mixed. The systemic, injectable musculoskeletal use the compound is most associated with has not been established in completed Phase 2 or Phase 3 human trials.
Reported safety in the trials conducted was generally favourable, with mostly mild, transient effects. Thymosin beta-4 is listed as a prohibited substance by the World Anti-Doping Agency.
A note on naming
Thymosin beta-4 and "TB-500" are used interchangeably in vendor and research contexts but should not be confused with thymosin alpha-1, a separate peptide with a substantially larger clinical-trial base and regulatory approvals in some jurisdictions. Conflating the two inflates the apparent evidence for TB-500.
What this evidence is — and isn’t
These trials studied pharmaceutical-grade TB-500 administered under medical supervision in controlled settings. The figures summarised in this dossier describe that published science only.
They are not outcomes associated with research-grade material, and not results attributable to any use of the product sold in this catalogue. Nothing here is an endorsement, recommendation, or instruction for human use.
Nexyra Lab Catalogue
This dossier covers published clinical research on TB-500. Nexyra Lab supplies research-grade TB-500 for in vitro laboratory use.
View TB-500 in the Nexyra catalogue (research use only) →References
- 1
Malinda KM, et al. Thymosin beta-4 accelerates wound healing. J Invest Dermatol. 1999.
- 2
Philp D, et al. Thymosin beta-4 and corneal wound healing. Not yet confirmed — owner to update. 2003.
- 3
RegeneRx Biopharmaceuticals. RGN-259 (ARISE Phase 2/3 dry-eye trials) and RGN-352 clinical programme records. RegeneRx clinical programme 2020.
Research & Laboratory Use Only
This dossier is compiled for research planning and educational purposes only. It summarises published scientific literature and does not constitute medical advice, dosing guidance, or a therapeutic claim. All Nexyra Lab products are for research purposes only and are not for human or veterinary use. Nothing in this document should be interpreted as recommending, endorsing, or facilitating the self-administration of any compound.
A one-time legal review of this template and disclaimer is recommended before the Journal section is made publicly accessible, given the health-adjacent nature of this content.